‹

Control Module

Transmission and Drivetrain › Relays and Modules - Transmission and Drivetrain
Unified entry — merged from multiple cross-listed pages in the original manual.

Labor

Replace — Control Module0.6 hr
Warranty 0.5 hrSkill B
Replace — Control Module0.6 hr
Warranty 0.5 hrSkill B
Procedures
Final Drive Control Module - Installation3 steps
Fig. 1
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  1. Connect the two electrical connectors (1) into the FDCM.
  2. Install the FDCM being certain the locking tabs (1) are secure.
  3. Raise the drivers side knee bolster.
Final Drive Control Module - Removal3 steps
ℹ NOTE
The FDCM has two electrical connectors and is installed inside the passenger compartment behind the driver side knee bolster and is mounted to the left kick panel. On RHD vehicles the FDCM is located in a mirrored position on the right side.
Fig. 1
Fig. 1
Fig. 2
Fig. 2
  1. Lower the drivers side knee bolster.
  2. Push out on the two locking tabs (1) and remove the FDCM.
  3. Disconnect the two electrical connectors (1) from the FDCM.
Final Drive Control Module - Operationreference
ℹ NOTE
There is no requirement for the FDCM to distinguish between a neutral request from the 4WD AUTO or the 4WD LOW position. Resistances in these ranges will be represented as a Neutral Switch Activation.
OPERATION During normal operation of an active transfer case the FDCM control module learns and remembers the Clutch Engagement Point (Kiss Point), the position in the motor actuator's travel where torque begins to be transferred to the front wheels. The position is read out using the encoder as a 0 to 5 volt signal. This information is written into the module's EEPROM area at Ignition OFF. Over time the clutch pack wears and the Kiss Point changes in one direction (going from a lower voltage to a higher value). POWER UP/DOWN The Final Drive Control Module (FDCM) will power up with an OFF/ON transition of the hard wired ignition switch input. The FDCM will power down when the vehicle ignition switch transitions from ON to OFF or there are no system requirements that dictate the controller to remain active START-UP DIAGNOSTICS When the FDCM is activated, the internal circuitry will undergo a diagnostic procedure. The controller will examine all inputs and outputs for short circuits to ground, short circuits to battery and open circuits and will also verify proper CPU and memory operation. If a fault is detected, a message will be sent out over the CAN C bus to the Cluster indicating that service is recommended. After passing all diagnostic tests, the controller will receive and process inputs and produce the appropriate outputs. Proper monitoring of the controller inputs and outputs performance will continue. INPUTS/OUTPUTS The following are inputs to the FDCM: -Transfer Case Mode Sensor Signal -1 Direct Battery Feeds -Ignition RUN Sense -Sensor Ground -Module Ground -CAN C Bus The following are outputs of the FDCM: -Transfer Case Motor Brake Control (3022 only) -5V Sensor Supply -Transfer Case Bi-directional Motor Control (A AND B) -Switched B+ Solenoid Supply -Transfer Case Motor Brake Control TRANSFER CASE RANGE SELECT SWITCH INPUT (NEUTRAL, 2WD, 4WD AUTO and 4WD LOW SELECT SWITCH) The transfer case range select switch is hardwired directly to the Cluster (CCN). The switch position is read by the CCN and is communicated to the TIPM (Gateway) via the CAN-I bus. The TIPM then rebroadcasts this information onto the CAN-C bus where the FDCM is a receiver. The Cluster (CCN) will support circuitry which interfaces to the system's Transfer Case Range Select Switch, including a Transfer Case Range Select Switch voltage supply and a Transfer Case Range Select Switch input. The purpose of this circuitry is to determine the mode currently being requested by the operator via the resistance ladder network in the shifter assembly, where the Transfer Case Range Select Switch is packaged. The NEUTRAL Select Switch Input will provide the operator with the ability to place the Transfer Case in Neutral. The Select Switch Input will provide the operator with the ability to place the transfer case in 2WD, 4WD AUTO and 4WD LOW. The NEUTRAL Select Switch is a momentary pushpin switch and the 2WD, 4WD AUTO and 4WD LOW Select Switch is a 3-position toggle or a contact switch and both these switches are provided through a resistor network for diagnostic purposes. The input will have an internal 1.0K +/- 1% pull-up resistor to 5V. As the selected position in the switch varies and/or the NEUTRAL Switch is depressed or not, the resistance between the Cluster (CCN) voltage supply and Transfer Case Range Select Switches input will vary. Hardware, software, and calibrations within the Cluster will be provided that interpret the external resistance between the module's Transfer Case Range Select Switches voltage supply and Transfer Case Range Select Switches inputs as given in the table below: TRANSFER CASE MODE SENSOR SIGNAL The Transfer Case Mode Sensor Signal Input will provide the FDCM feedback about the position of the transfer case. The mode sensor will be a linear analog position sensor with a 1.4K +/- 20% potentiometer and a 1 K +/- 20% wiper resistor that converts the motor shaft position into a multiplexed voltage. The mode sensor (on the 3022 transfer case) is an active device where the sensor's current changes as the motor shaft position changes TRANSFER CASE BI-DIRECTIONAL MOTOR CONTROL (A AND B) This output will control a Bi-directional DC motor that controls a clutch pack in the Transfer Case that varies the torque transfer between the front and rear axles. MODES OF OPERATION Normal Operation This mode is achieved by the ignition being switched in the RUN position, which powers up the 5V regulator and generates the appropriate RESET for the microprocessor. This mode also includes any required power-up system checks. Shut Down Mode This mode is activated when the ignition switch turned to the off position. The FDCM will perform any required Shut Down tasks prior to turning off the 5V regulator. Limp-In Mode This mode is entered when the FDCM has detected an error condition that prevents the system from performing its' required task. The FDCM operation will vary depending from modified operation to total system shut down based on the failure that has occurred.
Final Drive Control Module - Descriptionreference
Fig. 1
Fig. 1
DESCRIPTION The Final Drive Control Module (FDCM) is a microprocessor-based assembly controlling the Transfer Case. Communication is via the CAN serial bus. Inputs include user selectable 2WD and 4WD modes that include 2WD, 4WD AUTO, 4WD LOW and Neutral. The FDCM has two electrical connectors and is installed inside the passenger compartment behind the driver side knee bolster and is mounted to the left kick panel. On RHD vehicles the FDCM is located in a mirrored position on the right side.
TCM Quick Learnreference
TCM QUICK LEARN The quick learn procedure requires the use of the scan tool. This program allows the electronic transmission system to recalibrate itself. This will provide the proper transmission operation. The quick learn procedure should be performed if any of the following procedures are performed: -Transmission Assembly Replacement -Transmission Control Module Replacement -Solenoid Pack Replacement -Clutch Plate and/or Seal Replacement -Valve Body Replacement or Recondition To perform the Quick Learn Procedure, the following conditions must be met: -The brakes must be applied -The engine speed must be above 500 rpm -The throttle angle (TPS) must be less than three degrees -The shift lever position must stay in PARK until prompted to shift to overdrive -The shift lever position must stay in overdrive after the Shift to Overdrive prompt until the scan tool indicates the procedure is complete. -The calculated oil temperature must be above 16° C (60° F) and below 93° C (200° F).
TCM Drive Learn21 steps
ℹ NOTE
It is not necessary to perform the complete Drive Learn procedure every time the TCM is Quick Learned. Perform only the portions which target the objectionable shift.
ℹ NOTE
The transmission oil temperature must be between 27-43° C (80-110° F).
ℹ NOTE
It is important that this procedure be performed when the transmission temperature is between 27-43° C (80-110° F). If this procedure takes too long to complete fully for the allowed transmission oil temperature, the vehicle may be returned to the customer with an explanation that the shift will improve daily during normal vehicle usage. The TCM also learns at higher oil temperatures, but these values (line pressure correction values) are not available for viewing on the scan tool.
ℹ NOTE
The transmission oil temperature must be between 27-43° C (80-110° F) to learn the UD CVI. Additional learning occurs at temperatures as low as -18° C (0° F) and as high as 93° C (200° F). This procedure may be performed at any temperature that experiences poor shift quality. Although the UD CVI may not change, shift quality should improve.
ℹ NOTE
The transmission oil temperature must be above 27° C (80° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
  1. Start the engine only when the engine and ignition have been off for at least ten (10) minutes.
  2. With the vehicle at a stop and the service brake applied, record the 1st N-D UD CVI while performing a Neutral to Drive shift. The 1st N-D UD CVI accounts for air entrapment in the UD clutch that may occur after the engine has been off for a period of time.
  3. Repeat 1 and 2 until the recorded 1st N-D UD CVI value stabilizes. LEARN A SMOOTH NEUTRAL TO DRIVE GARAGE SHIFT Perform this procedure if the complaint is for a delayed or harsh shift when the transmission is put into gear after the vehicle has had its first shift. Use the following steps to have the TCM learn the Norm N-D UD CVI.
  4. Start the vehicle engine and shift to drive.
  5. Move the vehicle forward to a speed of at least 16 km/h (10 MPH) and come to a stop. This ensures no air is present in the UD hydraulic circuit.
  6. Perform repeated N-D shifts at a stop while pausing in Neutral for at least 2-3 seconds and monitor Norm N-D UD CVI volume until the value stabilizes. The value will change during the N-D shift. This is normal since the UD value is different for the N-D shift then the normal value shown which is used for 4-3 coastdown and kickdowns. Perform repeated shifts in this temperature range until the Norm N-D UD CVI value stabilizes and the N-D shifts become smooth. LEARN THE 1ST 2-3 SHIFT AFTER A RESTART OR SHIFT TO REVERSE Use the following steps to have the TCM learn the 1st 2-3 shift OD CVI.
  7. With the vehicle engine running, select reverse gear for over 2 seconds.
  8. Shift the transmission to Drive and accelerate the vehicle from a stop at a steady 15 degree throttle opening and perform a 2-3 shift while noting the 1st 2-3 OD CVI.
  9. Repeat 1 and 2 until the 1st 2-3 upshift becomes smooth and the 1st 2-3 OD CVI stabilizes. LEARN A SMOOTH 2-3 AND 3-4 UPSHIFT Use the following steps to have the TCM learn the OD and 4C CVI's.
  10. Accelerate the vehicle from a stop at a steady 15 degree throttle opening and perform multiple 1-2, 2-3, and 3-4 upshifts. The 2nd 2-3 shift following a restart or shift to reverse will be shown during the shift as a value between the 1st 2-3 OD CVI and the normal OD CVI. Updates to the normal OD CVI will occur after the 2nd shift into 3rd gear, following a restart or shift to reverse.
  11. Repeat 1 until the 2-3 and 3-4 shifts become smooth and the OD and 4C CVI become stable. LEARN A SMOOTH 4-3 COASTDOWN AND PART THROTTLE 4-3 KICKDOWN Use the following steps to have the TCM learn the UD shift volume.
  12. At a vehicle speed between 64-97 km/h (40-60 mph), perform repeated 4-3 kickdown shifts.
  13. Repeat 1 until the UD volume becomes somewhat stable and the shift becomes smooth. LEARN A SMOOTH 1-2 UPSHIFT AND 3-2 KICKDOWN Use the following steps to have the TCM learn the 2C shift volume.
  14. With a vehicle speed below 48 km/h (30 mph) and the transmission in 3rd gear, perform multiple 3-2 kickdowns.
  15. Repeat 1 until the 3-2 kickdowns become smooth and the 2C CVI becomes stable. LEARN A SMOOTH MANUAL 2-1 PULLDOWN SHIFT AS WELL AS A NEUTRAL TO REVERSE SHIFT Use the following steps to have the TCM learn the LR volume.
  16. With the vehicle speed around 40-48 km/h (25-30 mph) in Manual 2nd, perform manual pulldowns to Low or 1st gear at closed throttle.
  17. Repeat 1 until the LR CVI becomes stable and the manual 2-1 becomes smooth. LEARN A SMOOTH NEUTRAL TO REVERSE SHIFT
  18. With the vehicle at a stop, perform Neutral to Reverse shifts until the shift is smooth. An unlearned Neutral to Reverse shift may be harsh or exhibit a double bump.
  19. If any of the shifts are still not smooth after the clutch volume stabilizes, an internal transmission problem may be present. LEARN A SMOOTH 4-5 UPSHIFT Use the following steps to have the TCM learn the Alt 2C CVI.
  20. Accelerate the vehicle through 88 km/h (55 mph) at a steady 10-15 degree throttle opening and perform multiple 4-5 upshifts.
  21. Repeat 1 until the 4-5 shift become smooth and the Alt 2C CVI become stable. There is a separate 2C volume used and learned for 4-5 shifts, 2CA. It is independent of the 2C CVI learned on 3-2 kickdowns.
Transmission Control Module - Descriptionreference
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TRANSMISSION CONTROL MODULE - GASOLINE ENGINES The Transmission Control Module (TCM) is a sub-module within the Powertrain Control Module (PCM) (1). The PCM is located on the right inner fender. The NGC IV (fourth-generation) Powertrain Control Module (PCM) provides integrated electronic control of all transmission functions. If the vehicle is equipped with a NAG1 transmission the TCM (1) is a separate module located behind the drivers knee bolster to the right of the steering column.
Transmission Control Module - Operationreference
ℹ NOTE
If the TCM has been replaced, the "Quick Learn Procedure" must be performed.
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TRANSMISSION CONTROL MODULE - GASOLINE ENGINES The TCM is the controlling unit for all electronic operations of the transmission. The TCM receives information regarding vehicle operation from both direct and indirect inputs, and selects the operational mode of the transmission. Direct inputs are hard-wired to, and used specifically by the TCM. Indirect inputs originate from other components/modules, and are shared with the TCM via the CAN bus. Some examples of direct inputs to the TCM are: -Battery (B+) voltage -Ignition "ON" voltage -Transmission Control Relay (Switched B+) -Throttle Position Sensor -Crankshaft Position sensor (CKP) -Transmission Range Sensor (TRS) -Pressure Switches (L/R, 2/4, OD) -Transmission Temperature Sensor (TTS) (Integral to TRS) -Input Shaft Speed Sensor -Output Shaft Speed Sensor Some examples of indirect inputs to the TCM are: -Engine/Body Identification -Manifold Pressure -Target Idle -Torque Reduction Confirmation -Speed Control ON/OFF Switch -Engine Coolant Temperature -Ambient/Battery Temperature -Brake Switch Status -Scan Tool Communication Based on the information received from these various inputs, the TCM determines the appropriate shift schedule and shift points, depending on the present operating conditions and driver demand. This is possible through the control of various direct and indirect outputs. Some examples of TCM direct outputs are: -Transmission Control Relay -Solenoids (L/R, 2/4, OD and UD) -Vehicle Speed (to PCM) -Torque Reduction Request (to PCM) Some examples of TCM indirect outputs are: -Transmission Temperature (to PCM) -PRNDL Position (to CCN) In addition to monitoring inputs and controlling outputs, the TCM has other important responsibilities and functions: -Storing and maintaining Clutch Volume Indices (CVI) -Storing and selecting appropriate Shift Schedules -System self-diagnostics -Diagnostic capabilities (with scan tool) TCM Quick Learn CLUTCH VOLUME INDEX (CVI) An important function of the TCM is to monitor Clutch Volume Index (CVI). CVIs represent the volume of fluid needed to compress a clutch pack. The TCM monitors gear ratio changes by monitoring the Input and Output Speed Sensors. The Input, or Turbine Speed Sensor sends an electrical signal to the TCM that represents input shaft rpm. The Output Speed Sensor provides the TCM with output shaft speed information. By comparing the two inputs, the TCM can determine transmission gear position. This is important to the CVI calculation because the TCM determines CVIs by monitoring how long it takes for a gear change to occur Gear ratios can be determined by using the scan tool and reading the Input/Output Speed Sensor values in the "Monitors" display. Gear ratio can be obtained by dividing the Input Speed Sensor value by the Output Speed Sensor value. For example, if the input shaft is rotating at 1000 rpm and the output shaft is rotating at 500 rpm, then the TCM can determine that the gear ratio is 2:1. In direct drive (3rd gear), the gear ratio changes to 1:1. The gear ratio changes as clutches are applied and released. By monitoring the length of time it takes for the gear ratio to change following a shift request, the TCM can determine the volume of fluid used to apply or release a friction element. The volume of transmission fluid needed to apply the friction elements are continuously updated for adaptive controls. As friction material wears, the volume of fluid need to apply the element increases. Certain mechanical problems within the input clutch assembly (broken return springs, out of position snap rings, excessive clutch pack clearance, improper assembly, etc.) can cause inadequate or out-of-range element volumes. Also, defective Input/Output Speed Sensors and wiring can cause these conditions. The following chart identifies the appropriate clutch volumes and when they are monitored/updated: SHIFT SCHEDULES As mentioned earlier, the TCM has programming that allows it to select a variety of shift schedules. Shift schedule selection is dependent on the following: -Shift lever position -Throttle position -Engine load -Fluid temperature -Software level As driving conditions change, the TCM appropriately adjusts the shift schedule. Refer to the following table 42RLE Shift Schedule to determine the appropriate operation expected, depending on driving conditions. 42RLE Shift Schedule
Final Drive Control Module - Installation3 steps
Fig. 1
Fig. 1
Fig. 2
Fig. 2
  1. Connect the two electrical connectors (1) into the FDCM.
  2. Install the FDCM being certain the locking tabs (1) are secure.
  3. Raise the drivers side knee bolster.
Final Drive Control Module - Removal3 steps
ℹ NOTE
The FDCM has two electrical connectors and is installed inside the passenger compartment behind the driver side knee bolster and is mounted to the left kick panel. On RHD vehicles the FDCM is located in a mirrored position on the right side.
Fig. 1
Fig. 1
Fig. 2
Fig. 2
  1. Lower the drivers side knee bolster.
  2. Push out on the two locking tabs (1) and remove the FDCM.
  3. Disconnect the two electrical connectors (1) from the FDCM.
Final Drive Control Module - Operationreference
ℹ NOTE
There is no requirement for the FDCM to distinguish between a neutral request from the 4WD AUTO or the 4WD LOW position. Resistances in these ranges will be represented as a Neutral Switch Activation.
OPERATION During normal operation of an active transfer case the FDCM control module learns and remembers the Clutch Engagement Point (Kiss Point), the position in the motor actuator's travel where torque begins to be transferred to the front wheels. The position is read out using the encoder as a 0 to 5 volt signal. This information is written into the module's EEPROM area at Ignition OFF. Over time the clutch pack wears and the Kiss Point changes in one direction (going from a lower voltage to a higher value). POWER UP/DOWN The Final Drive Control Module (FDCM) will power up with an OFF/ON transition of the hard wired ignition switch input. The FDCM will power down when the vehicle ignition switch transitions from ON to OFF or there are no system requirements that dictate the controller to remain active START-UP DIAGNOSTICS When the FDCM is activated, the internal circuitry will undergo a diagnostic procedure. The controller will examine all inputs and outputs for short circuits to ground, short circuits to battery and open circuits and will also verify proper CPU and memory operation. If a fault is detected, a message will be sent out over the CAN C bus to the Cluster indicating that service is recommended. After passing all diagnostic tests, the controller will receive and process inputs and produce the appropriate outputs. Proper monitoring of the controller inputs and outputs performance will continue. INPUTS/OUTPUTS The following are inputs to the FDCM: -Transfer Case Mode Sensor Signal -1 Direct Battery Feeds -Ignition RUN Sense -Sensor Ground -Module Ground -CAN C Bus The following are outputs of the FDCM: -Transfer Case Motor Brake Control (3022 only) -5V Sensor Supply -Transfer Case Bi-directional Motor Control (A AND B) -Switched B+ Solenoid Supply -Transfer Case Motor Brake Control TRANSFER CASE RANGE SELECT SWITCH INPUT (NEUTRAL, 2WD, 4WD AUTO and 4WD LOW SELECT SWITCH) The transfer case range select switch is hardwired directly to the Cluster (CCN). The switch position is read by the CCN and is communicated to the TIPM (Gateway) via the CAN-I bus. The TIPM then rebroadcasts this information onto the CAN-C bus where the FDCM is a receiver. The Cluster (CCN) will support circuitry which interfaces to the system's Transfer Case Range Select Switch, including a Transfer Case Range Select Switch voltage supply and a Transfer Case Range Select Switch input. The purpose of this circuitry is to determine the mode currently being requested by the operator via the resistance ladder network in the shifter assembly, where the Transfer Case Range Select Switch is packaged. The NEUTRAL Select Switch Input will provide the operator with the ability to place the Transfer Case in Neutral. The Select Switch Input will provide the operator with the ability to place the transfer case in 2WD, 4WD AUTO and 4WD LOW. The NEUTRAL Select Switch is a momentary pushpin switch and the 2WD, 4WD AUTO and 4WD LOW Select Switch is a 3-position toggle or a contact switch and both these switches are provided through a resistor network for diagnostic purposes. The input will have an internal 1.0K +/- 1% pull-up resistor to 5V. As the selected position in the switch varies and/or the NEUTRAL Switch is depressed or not, the resistance between the Cluster (CCN) voltage supply and Transfer Case Range Select Switches input will vary. Hardware, software, and calibrations within the Cluster will be provided that interpret the external resistance between the module's Transfer Case Range Select Switches voltage supply and Transfer Case Range Select Switches inputs as given in the table below: TRANSFER CASE MODE SENSOR SIGNAL The Transfer Case Mode Sensor Signal Input will provide the FDCM feedback about the position of the transfer case. The mode sensor will be a linear analog position sensor with a 1.4K +/- 20% potentiometer and a 1 K +/- 20% wiper resistor that converts the motor shaft position into a multiplexed voltage. The mode sensor (on the 3022 transfer case) is an active device where the sensor's current changes as the motor shaft position changes TRANSFER CASE BI-DIRECTIONAL MOTOR CONTROL (A AND B) This output will control a Bi-directional DC motor that controls a clutch pack in the Transfer Case that varies the torque transfer between the front and rear axles. MODES OF OPERATION Normal Operation This mode is achieved by the ignition being switched in the RUN position, which powers up the 5V regulator and generates the appropriate RESET for the microprocessor. This mode also includes any required power-up system checks. Shut Down Mode This mode is activated when the ignition switch turned to the off position. The FDCM will perform any required Shut Down tasks prior to turning off the 5V regulator. Limp-In Mode This mode is entered when the FDCM has detected an error condition that prevents the system from performing its' required task. The FDCM operation will vary depending from modified operation to total system shut down based on the failure that has occurred.
Final Drive Control Module - Descriptionreference
Fig. 1
Fig. 1
DESCRIPTION The Final Drive Control Module (FDCM) is a microprocessor-based assembly controlling the Transfer Case. Communication is via the CAN serial bus. Inputs include user selectable 2WD and 4WD modes that include 2WD, 4WD AUTO, 4WD LOW and Neutral. The FDCM has two electrical connectors and is installed inside the passenger compartment behind the driver side knee bolster and is mounted to the left kick panel. On RHD vehicles the FDCM is located in a mirrored position on the right side.
Final Drive Control Module - Installation3 steps
Fig. 1
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Fig. 2
Fig. 2
  1. Connect the two electrical connectors (1) into the FDCM.
  2. Install the FDCM being certain the locking tabs (1) are secure.
  3. Raise the drivers side knee bolster.
Final Drive Control Module - Removal3 steps
ℹ NOTE
The FDCM has two electrical connectors and is installed inside the passenger compartment behind the driver side knee bolster and is mounted to the left kick panel. On RHD vehicles the FDCM is located in a mirrored position on the right side.
Fig. 1
Fig. 1
Fig. 2
Fig. 2
  1. Lower the drivers side knee bolster.
  2. Push out on the two locking tabs (1) and remove the FDCM.
  3. Disconnect the two electrical connectors (1) from the FDCM.
Final Drive Control Module - Operationreference
ℹ NOTE
There is no requirement for the FDCM to distinguish between a neutral request from the 4WD AUTO or the 4WD LOW position. Resistances in these ranges will be represented as a Neutral Switch Activation.
OPERATION During normal operation of an active transfer case the FDCM control module learns and remembers the Clutch Engagement Point (Kiss Point), the position in the motor actuator's travel where torque begins to be transferred to the front wheels. The position is read out using the encoder as a 0 to 5 volt signal. This information is written into the module's EEPROM area at Ignition OFF. Over time the clutch pack wears and the Kiss Point changes in one direction (going from a lower voltage to a higher value). POWER UP/DOWN The Final Drive Control Module (FDCM) will power up with an OFF/ON transition of the hard wired ignition switch input. The FDCM will power down when the vehicle ignition switch transitions from ON to OFF or there are no system requirements that dictate the controller to remain active START-UP DIAGNOSTICS When the FDCM is activated, the internal circuitry will undergo a diagnostic procedure. The controller will examine all inputs and outputs for short circuits to ground, short circuits to battery and open circuits and will also verify proper CPU and memory operation. If a fault is detected, a message will be sent out over the CAN C bus to the Cluster indicating that service is recommended. After passing all diagnostic tests, the controller will receive and process inputs and produce the appropriate outputs. Proper monitoring of the controller inputs and outputs performance will continue. INPUTS/OUTPUTS The following are inputs to the FDCM: -Transfer Case Mode Sensor Signal -1 Direct Battery Feeds -Ignition RUN Sense -Sensor Ground -Module Ground -CAN C Bus The following are outputs of the FDCM: -Transfer Case Motor Brake Control (3022 only) -5V Sensor Supply -Transfer Case Bi-directional Motor Control (A AND B) -Switched B+ Solenoid Supply -Transfer Case Motor Brake Control TRANSFER CASE RANGE SELECT SWITCH INPUT (NEUTRAL, 2WD, 4WD AUTO and 4WD LOW SELECT SWITCH) The transfer case range select switch is hardwired directly to the Cluster (CCN). The switch position is read by the CCN and is communicated to the TIPM (Gateway) via the CAN-I bus. The TIPM then rebroadcasts this information onto the CAN-C bus where the FDCM is a receiver. The Cluster (CCN) will support circuitry which interfaces to the system's Transfer Case Range Select Switch, including a Transfer Case Range Select Switch voltage supply and a Transfer Case Range Select Switch input. The purpose of this circuitry is to determine the mode currently being requested by the operator via the resistance ladder network in the shifter assembly, where the Transfer Case Range Select Switch is packaged. The NEUTRAL Select Switch Input will provide the operator with the ability to place the Transfer Case in Neutral. The Select Switch Input will provide the operator with the ability to place the transfer case in 2WD, 4WD AUTO and 4WD LOW. The NEUTRAL Select Switch is a momentary pushpin switch and the 2WD, 4WD AUTO and 4WD LOW Select Switch is a 3-position toggle or a contact switch and both these switches are provided through a resistor network for diagnostic purposes. The input will have an internal 1.0K +/- 1% pull-up resistor to 5V. As the selected position in the switch varies and/or the NEUTRAL Switch is depressed or not, the resistance between the Cluster (CCN) voltage supply and Transfer Case Range Select Switches input will vary. Hardware, software, and calibrations within the Cluster will be provided that interpret the external resistance between the module's Transfer Case Range Select Switches voltage supply and Transfer Case Range Select Switches inputs as given in the table below: TRANSFER CASE MODE SENSOR SIGNAL The Transfer Case Mode Sensor Signal Input will provide the FDCM feedback about the position of the transfer case. The mode sensor will be a linear analog position sensor with a 1.4K +/- 20% potentiometer and a 1 K +/- 20% wiper resistor that converts the motor shaft position into a multiplexed voltage. The mode sensor (on the 3022 transfer case) is an active device where the sensor's current changes as the motor shaft position changes TRANSFER CASE BI-DIRECTIONAL MOTOR CONTROL (A AND B) This output will control a Bi-directional DC motor that controls a clutch pack in the Transfer Case that varies the torque transfer between the front and rear axles. MODES OF OPERATION Normal Operation This mode is achieved by the ignition being switched in the RUN position, which powers up the 5V regulator and generates the appropriate RESET for the microprocessor. This mode also includes any required power-up system checks. Shut Down Mode This mode is activated when the ignition switch turned to the off position. The FDCM will perform any required Shut Down tasks prior to turning off the 5V regulator. Limp-In Mode This mode is entered when the FDCM has detected an error condition that prevents the system from performing its' required task. The FDCM operation will vary depending from modified operation to total system shut down based on the failure that has occurred.
Final Drive Control Module - Descriptionreference
Fig. 1
Fig. 1
DESCRIPTION The Final Drive Control Module (FDCM) is a microprocessor-based assembly controlling the Transfer Case. Communication is via the CAN serial bus. Inputs include user selectable 2WD and 4WD modes that include 2WD, 4WD AUTO, 4WD LOW and Neutral. The FDCM has two electrical connectors and is installed inside the passenger compartment behind the driver side knee bolster and is mounted to the left kick panel. On RHD vehicles the FDCM is located in a mirrored position on the right side.
TCM Quick Learnreference
TCM QUICK LEARN The quick learn procedure requires the use of the scan tool. This program allows the electronic transmission system to recalibrate itself. This will provide the proper transmission operation. The quick learn procedure should be performed if any of the following procedures are performed: -Transmission Assembly Replacement -Transmission Control Module Replacement -Solenoid Pack Replacement -Clutch Plate and/or Seal Replacement -Valve Body Replacement or Recondition To perform the Quick Learn Procedure, the following conditions must be met: -The brakes must be applied -The engine speed must be above 500 rpm -The throttle angle (TPS) must be less than three degrees -The shift lever position must stay in PARK until prompted to shift to overdrive -The shift lever position must stay in overdrive after the Shift to Overdrive prompt until the scan tool indicates the procedure is complete. -The calculated oil temperature must be above 16° C (60° F) and below 93° C (200° F).
TCM Drive Learn21 steps
ℹ NOTE
It is not necessary to perform the complete Drive Learn procedure every time the TCM is Quick Learned. Perform only the portions which target the objectionable shift.
ℹ NOTE
The transmission oil temperature must be between 27-43° C (80-110° F).
ℹ NOTE
It is important that this procedure be performed when the transmission temperature is between 27-43° C (80-110° F). If this procedure takes too long to complete fully for the allowed transmission oil temperature, the vehicle may be returned to the customer with an explanation that the shift will improve daily during normal vehicle usage. The TCM also learns at higher oil temperatures, but these values (line pressure correction values) are not available for viewing on the scan tool.
ℹ NOTE
The transmission oil temperature must be between 27-43° C (80-110° F) to learn the UD CVI. Additional learning occurs at temperatures as low as -18° C (0° F) and as high as 93° C (200° F). This procedure may be performed at any temperature that experiences poor shift quality. Although the UD CVI may not change, shift quality should improve.
ℹ NOTE
The transmission oil temperature must be above 27° C (80° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
  1. Start the engine only when the engine and ignition have been off for at least ten (10) minutes.
  2. With the vehicle at a stop and the service brake applied, record the 1st N-D UD CVI while performing a Neutral to Drive shift. The 1st N-D UD CVI accounts for air entrapment in the UD clutch that may occur after the engine has been off for a period of time.
  3. Repeat 1 and 2 until the recorded 1st N-D UD CVI value stabilizes. LEARN A SMOOTH NEUTRAL TO DRIVE GARAGE SHIFT Perform this procedure if the complaint is for a delayed or harsh shift when the transmission is put into gear after the vehicle has had its first shift. Use the following steps to have the TCM learn the Norm N-D UD CVI.
  4. Start the vehicle engine and shift to drive.
  5. Move the vehicle forward to a speed of at least 16 km/h (10 MPH) and come to a stop. This ensures no air is present in the UD hydraulic circuit.
  6. Perform repeated N-D shifts at a stop while pausing in Neutral for at least 2-3 seconds and monitor Norm N-D UD CVI volume until the value stabilizes. The value will change during the N-D shift. This is normal since the UD value is different for the N-D shift then the normal value shown which is used for 4-3 coastdown and kickdowns. Perform repeated shifts in this temperature range until the Norm N-D UD CVI value stabilizes and the N-D shifts become smooth. LEARN THE 1ST 2-3 SHIFT AFTER A RESTART OR SHIFT TO REVERSE Use the following steps to have the TCM learn the 1st 2-3 shift OD CVI.
  7. With the vehicle engine running, select reverse gear for over 2 seconds.
  8. Shift the transmission to Drive and accelerate the vehicle from a stop at a steady 15 degree throttle opening and perform a 2-3 shift while noting the 1st 2-3 OD CVI.
  9. Repeat 1 and 2 until the 1st 2-3 upshift becomes smooth and the 1st 2-3 OD CVI stabilizes. LEARN A SMOOTH 2-3 AND 3-4 UPSHIFT Use the following steps to have the TCM learn the OD and 4C CVI's.
  10. Accelerate the vehicle from a stop at a steady 15 degree throttle opening and perform multiple 1-2, 2-3, and 3-4 upshifts. The 2nd 2-3 shift following a restart or shift to reverse will be shown during the shift as a value between the 1st 2-3 OD CVI and the normal OD CVI. Updates to the normal OD CVI will occur after the 2nd shift into 3rd gear, following a restart or shift to reverse.
  11. Repeat 1 until the 2-3 and 3-4 shifts become smooth and the OD and 4C CVI become stable. LEARN A SMOOTH 4-3 COASTDOWN AND PART THROTTLE 4-3 KICKDOWN Use the following steps to have the TCM learn the UD shift volume.
  12. At a vehicle speed between 64-97 km/h (40-60 mph), perform repeated 4-3 kickdown shifts.
  13. Repeat 1 until the UD volume becomes somewhat stable and the shift becomes smooth. LEARN A SMOOTH 1-2 UPSHIFT AND 3-2 KICKDOWN Use the following steps to have the TCM learn the 2C shift volume.
  14. With a vehicle speed below 48 km/h (30 mph) and the transmission in 3rd gear, perform multiple 3-2 kickdowns.
  15. Repeat 1 until the 3-2 kickdowns become smooth and the 2C CVI becomes stable. LEARN A SMOOTH MANUAL 2-1 PULLDOWN SHIFT AS WELL AS A NEUTRAL TO REVERSE SHIFT Use the following steps to have the TCM learn the LR volume.
  16. With the vehicle speed around 40-48 km/h (25-30 mph) in Manual 2nd, perform manual pulldowns to Low or 1st gear at closed throttle.
  17. Repeat 1 until the LR CVI becomes stable and the manual 2-1 becomes smooth. LEARN A SMOOTH NEUTRAL TO REVERSE SHIFT
  18. With the vehicle at a stop, perform Neutral to Reverse shifts until the shift is smooth. An unlearned Neutral to Reverse shift may be harsh or exhibit a double bump.
  19. If any of the shifts are still not smooth after the clutch volume stabilizes, an internal transmission problem may be present. LEARN A SMOOTH 4-5 UPSHIFT Use the following steps to have the TCM learn the Alt 2C CVI.
  20. Accelerate the vehicle through 88 km/h (55 mph) at a steady 10-15 degree throttle opening and perform multiple 4-5 upshifts.
  21. Repeat 1 until the 4-5 shift become smooth and the Alt 2C CVI become stable. There is a separate 2C volume used and learned for 4-5 shifts, 2CA. It is independent of the 2C CVI learned on 3-2 kickdowns.
Transmission Control Module - Descriptionreference
Fig. 1
Fig. 1
Fig. 2
Fig. 2
Fig. 3
Fig. 3
Fig. 4
Fig. 4
TRANSMISSION CONTROL MODULE - GASOLINE ENGINES The Transmission Control Module (TCM) is a sub-module within the Powertrain Control Module (PCM) (1). The PCM is located on the right inner fender. The NGC IV (fourth-generation) Powertrain Control Module (PCM) provides integrated electronic control of all transmission functions. If the vehicle is equipped with a NAG1 transmission the TCM (1) is a separate module located behind the drivers knee bolster to the right of the steering column.
Transmission Control Module - Operationreference
ℹ NOTE
If the TCM has been replaced, the "Quick Learn Procedure" must be performed.
Fig. 1
Fig. 1
Fig. 2
Fig. 2
Fig. 3
Fig. 3
Fig. 4
Fig. 4
TRANSMISSION CONTROL MODULE - GASOLINE ENGINES The TCM is the controlling unit for all electronic operations of the transmission. The TCM receives information regarding vehicle operation from both direct and indirect inputs, and selects the operational mode of the transmission. Direct inputs are hard-wired to, and used specifically by the TCM. Indirect inputs originate from other components/modules, and are shared with the TCM via the CAN bus. Some examples of direct inputs to the TCM are: -Battery (B+) voltage -Ignition "ON" voltage -Transmission Control Relay (Switched B+) -Throttle Position Sensor -Crankshaft Position sensor (CKP) -Transmission Range Sensor (TRS) -Pressure Switches (L/R, 2/4, OD) -Transmission Temperature Sensor (TTS) (Integral to TRS) -Input Shaft Speed Sensor -Output Shaft Speed Sensor Some examples of indirect inputs to the TCM are: -Engine/Body Identification -Manifold Pressure -Target Idle -Torque Reduction Confirmation -Speed Control ON/OFF Switch -Engine Coolant Temperature -Ambient/Battery Temperature -Brake Switch Status -Scan Tool Communication Based on the information received from these various inputs, the TCM determines the appropriate shift schedule and shift points, depending on the present operating conditions and driver demand. This is possible through the control of various direct and indirect outputs. Some examples of TCM direct outputs are: -Transmission Control Relay -Solenoids (L/R, 2/4, OD and UD) -Vehicle Speed (to PCM) -Torque Reduction Request (to PCM) Some examples of TCM indirect outputs are: -Transmission Temperature (to PCM) -PRNDL Position (to CCN) In addition to monitoring inputs and controlling outputs, the TCM has other important responsibilities and functions: -Storing and maintaining Clutch Volume Indices (CVI) -Storing and selecting appropriate Shift Schedules -System self-diagnostics -Diagnostic capabilities (with scan tool) TCM Quick Learn CLUTCH VOLUME INDEX (CVI) An important function of the TCM is to monitor Clutch Volume Index (CVI). CVIs represent the volume of fluid needed to compress a clutch pack. The TCM monitors gear ratio changes by monitoring the Input and Output Speed Sensors. The Input, or Turbine Speed Sensor sends an electrical signal to the TCM that represents input shaft rpm. The Output Speed Sensor provides the TCM with output shaft speed information. By comparing the two inputs, the TCM can determine transmission gear position. This is important to the CVI calculation because the TCM determines CVIs by monitoring how long it takes for a gear change to occur Gear ratios can be determined by using the scan tool and reading the Input/Output Speed Sensor values in the "Monitors" display. Gear ratio can be obtained by dividing the Input Speed Sensor value by the Output Speed Sensor value. For example, if the input shaft is rotating at 1000 rpm and the output shaft is rotating at 500 rpm, then the TCM can determine that the gear ratio is 2:1. In direct drive (3rd gear), the gear ratio changes to 1:1. The gear ratio changes as clutches are applied and released. By monitoring the length of time it takes for the gear ratio to change following a shift request, the TCM can determine the volume of fluid used to apply or release a friction element. The volume of transmission fluid needed to apply the friction elements are continuously updated for adaptive controls. As friction material wears, the volume of fluid need to apply the element increases. Certain mechanical problems within the input clutch assembly (broken return springs, out of position snap rings, excessive clutch pack clearance, improper assembly, etc.) can cause inadequate or out-of-range element volumes. Also, defective Input/Output Speed Sensors and wiring can cause these conditions. The following chart identifies the appropriate clutch volumes and when they are monitored/updated: SHIFT SCHEDULES As mentioned earlier, the TCM has programming that allows it to select a variety of shift schedules. Shift schedule selection is dependent on the following: -Shift lever position -Throttle position -Engine load -Fluid temperature -Software level As driving conditions change, the TCM appropriately adjusts the shift schedule. Refer to the following table 42RLE Shift Schedule to determine the appropriate operation expected, depending on driving conditions. 42RLE Shift Schedule
TCM Quick Learnreference
TCM QUICK LEARN The quick learn procedure requires the use of the scan tool. This program allows the electronic transmission system to recalibrate itself. This will provide the proper transmission operation. The quick learn procedure should be performed if any of the following procedures are performed: -Transmission Assembly Replacement -Transmission Control Module Replacement -Solenoid Pack Replacement -Clutch Plate and/or Seal Replacement -Valve Body Replacement or Recondition To perform the Quick Learn Procedure, the following conditions must be met: -The brakes must be applied -The engine speed must be above 500 rpm -The throttle angle (TPS) must be less than three degrees -The shift lever position must stay in PARK until prompted to shift to overdrive -The shift lever position must stay in overdrive after the Shift to Overdrive prompt until the scan tool indicates the procedure is complete. -The calculated oil temperature must be above 16° C (60° F) and below 93° C (200° F).
TCM Drive Learn21 steps
ℹ NOTE
It is not necessary to perform the complete Drive Learn procedure every time the TCM is Quick Learned. Perform only the portions which target the objectionable shift.
ℹ NOTE
The transmission oil temperature must be between 27-43° C (80-110° F).
ℹ NOTE
It is important that this procedure be performed when the transmission temperature is between 27-43° C (80-110° F). If this procedure takes too long to complete fully for the allowed transmission oil temperature, the vehicle may be returned to the customer with an explanation that the shift will improve daily during normal vehicle usage. The TCM also learns at higher oil temperatures, but these values (line pressure correction values) are not available for viewing on the scan tool.
ℹ NOTE
The transmission oil temperature must be between 27-43° C (80-110° F) to learn the UD CVI. Additional learning occurs at temperatures as low as -18° C (0° F) and as high as 93° C (200° F). This procedure may be performed at any temperature that experiences poor shift quality. Although the UD CVI may not change, shift quality should improve.
ℹ NOTE
The transmission oil temperature must be above 27° C (80° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
  1. Start the engine only when the engine and ignition have been off for at least ten (10) minutes.
  2. With the vehicle at a stop and the service brake applied, record the 1st N-D UD CVI while performing a Neutral to Drive shift. The 1st N-D UD CVI accounts for air entrapment in the UD clutch that may occur after the engine has been off for a period of time.
  3. Repeat 1 and 2 until the recorded 1st N-D UD CVI value stabilizes. LEARN A SMOOTH NEUTRAL TO DRIVE GARAGE SHIFT Perform this procedure if the complaint is for a delayed or harsh shift when the transmission is put into gear after the vehicle has had its first shift. Use the following steps to have the TCM learn the Norm N-D UD CVI.
  4. Start the vehicle engine and shift to drive.
  5. Move the vehicle forward to a speed of at least 16 km/h (10 MPH) and come to a stop. This ensures no air is present in the UD hydraulic circuit.
  6. Perform repeated N-D shifts at a stop while pausing in Neutral for at least 2-3 seconds and monitor Norm N-D UD CVI volume until the value stabilizes. The value will change during the N-D shift. This is normal since the UD value is different for the N-D shift then the normal value shown which is used for 4-3 coastdown and kickdowns. Perform repeated shifts in this temperature range until the Norm N-D UD CVI value stabilizes and the N-D shifts become smooth. LEARN THE 1ST 2-3 SHIFT AFTER A RESTART OR SHIFT TO REVERSE Use the following steps to have the TCM learn the 1st 2-3 shift OD CVI.
  7. With the vehicle engine running, select reverse gear for over 2 seconds.
  8. Shift the transmission to Drive and accelerate the vehicle from a stop at a steady 15 degree throttle opening and perform a 2-3 shift while noting the 1st 2-3 OD CVI.
  9. Repeat 1 and 2 until the 1st 2-3 upshift becomes smooth and the 1st 2-3 OD CVI stabilizes. LEARN A SMOOTH 2-3 AND 3-4 UPSHIFT Use the following steps to have the TCM learn the OD and 4C CVI's.
  10. Accelerate the vehicle from a stop at a steady 15 degree throttle opening and perform multiple 1-2, 2-3, and 3-4 upshifts. The 2nd 2-3 shift following a restart or shift to reverse will be shown during the shift as a value between the 1st 2-3 OD CVI and the normal OD CVI. Updates to the normal OD CVI will occur after the 2nd shift into 3rd gear, following a restart or shift to reverse.
  11. Repeat 1 until the 2-3 and 3-4 shifts become smooth and the OD and 4C CVI become stable. LEARN A SMOOTH 4-3 COASTDOWN AND PART THROTTLE 4-3 KICKDOWN Use the following steps to have the TCM learn the UD shift volume.
  12. At a vehicle speed between 64-97 km/h (40-60 mph), perform repeated 4-3 kickdown shifts.
  13. Repeat 1 until the UD volume becomes somewhat stable and the shift becomes smooth. LEARN A SMOOTH 1-2 UPSHIFT AND 3-2 KICKDOWN Use the following steps to have the TCM learn the 2C shift volume.
  14. With a vehicle speed below 48 km/h (30 mph) and the transmission in 3rd gear, perform multiple 3-2 kickdowns.
  15. Repeat 1 until the 3-2 kickdowns become smooth and the 2C CVI becomes stable. LEARN A SMOOTH MANUAL 2-1 PULLDOWN SHIFT AS WELL AS A NEUTRAL TO REVERSE SHIFT Use the following steps to have the TCM learn the LR volume.
  16. With the vehicle speed around 40-48 km/h (25-30 mph) in Manual 2nd, perform manual pulldowns to Low or 1st gear at closed throttle.
  17. Repeat 1 until the LR CVI becomes stable and the manual 2-1 becomes smooth. LEARN A SMOOTH NEUTRAL TO REVERSE SHIFT
  18. With the vehicle at a stop, perform Neutral to Reverse shifts until the shift is smooth. An unlearned Neutral to Reverse shift may be harsh or exhibit a double bump.
  19. If any of the shifts are still not smooth after the clutch volume stabilizes, an internal transmission problem may be present. LEARN A SMOOTH 4-5 UPSHIFT Use the following steps to have the TCM learn the Alt 2C CVI.
  20. Accelerate the vehicle through 88 km/h (55 mph) at a steady 10-15 degree throttle opening and perform multiple 4-5 upshifts.
  21. Repeat 1 until the 4-5 shift become smooth and the Alt 2C CVI become stable. There is a separate 2C volume used and learned for 4-5 shifts, 2CA. It is independent of the 2C CVI learned on 3-2 kickdowns.
Transmission Control Module - Descriptionreference
Fig. 1
Fig. 1
Fig. 2
Fig. 2
Fig. 3
Fig. 3
Fig. 4
Fig. 4
TRANSMISSION CONTROL MODULE - GASOLINE ENGINES The Transmission Control Module (TCM) is a sub-module within the Powertrain Control Module (PCM) (1). The PCM is located on the right inner fender. The NGC IV (fourth-generation) Powertrain Control Module (PCM) provides integrated electronic control of all transmission functions. If the vehicle is equipped with a NAG1 transmission the TCM (1) is a separate module located behind the drivers knee bolster to the right of the steering column.
Transmission Control Module - Operationreference
ℹ NOTE
If the TCM has been replaced, the "Quick Learn Procedure" must be performed.
Fig. 1
Fig. 1
Fig. 2
Fig. 2
Fig. 3
Fig. 3
Fig. 4
Fig. 4
TRANSMISSION CONTROL MODULE - GASOLINE ENGINES The TCM is the controlling unit for all electronic operations of the transmission. The TCM receives information regarding vehicle operation from both direct and indirect inputs, and selects the operational mode of the transmission. Direct inputs are hard-wired to, and used specifically by the TCM. Indirect inputs originate from other components/modules, and are shared with the TCM via the CAN bus. Some examples of direct inputs to the TCM are: -Battery (B+) voltage -Ignition "ON" voltage -Transmission Control Relay (Switched B+) -Throttle Position Sensor -Crankshaft Position sensor (CKP) -Transmission Range Sensor (TRS) -Pressure Switches (L/R, 2/4, OD) -Transmission Temperature Sensor (TTS) (Integral to TRS) -Input Shaft Speed Sensor -Output Shaft Speed Sensor Some examples of indirect inputs to the TCM are: -Engine/Body Identification -Manifold Pressure -Target Idle -Torque Reduction Confirmation -Speed Control ON/OFF Switch -Engine Coolant Temperature -Ambient/Battery Temperature -Brake Switch Status -Scan Tool Communication Based on the information received from these various inputs, the TCM determines the appropriate shift schedule and shift points, depending on the present operating conditions and driver demand. This is possible through the control of various direct and indirect outputs. Some examples of TCM direct outputs are: -Transmission Control Relay -Solenoids (L/R, 2/4, OD and UD) -Vehicle Speed (to PCM) -Torque Reduction Request (to PCM) Some examples of TCM indirect outputs are: -Transmission Temperature (to PCM) -PRNDL Position (to CCN) In addition to monitoring inputs and controlling outputs, the TCM has other important responsibilities and functions: -Storing and maintaining Clutch Volume Indices (CVI) -Storing and selecting appropriate Shift Schedules -System self-diagnostics -Diagnostic capabilities (with scan tool) TCM Quick Learn CLUTCH VOLUME INDEX (CVI) An important function of the TCM is to monitor Clutch Volume Index (CVI). CVIs represent the volume of fluid needed to compress a clutch pack. The TCM monitors gear ratio changes by monitoring the Input and Output Speed Sensors. The Input, or Turbine Speed Sensor sends an electrical signal to the TCM that represents input shaft rpm. The Output Speed Sensor provides the TCM with output shaft speed information. By comparing the two inputs, the TCM can determine transmission gear position. This is important to the CVI calculation because the TCM determines CVIs by monitoring how long it takes for a gear change to occur Gear ratios can be determined by using the scan tool and reading the Input/Output Speed Sensor values in the "Monitors" display. Gear ratio can be obtained by dividing the Input Speed Sensor value by the Output Speed Sensor value. For example, if the input shaft is rotating at 1000 rpm and the output shaft is rotating at 500 rpm, then the TCM can determine that the gear ratio is 2:1. In direct drive (3rd gear), the gear ratio changes to 1:1. The gear ratio changes as clutches are applied and released. By monitoring the length of time it takes for the gear ratio to change following a shift request, the TCM can determine the volume of fluid used to apply or release a friction element. The volume of transmission fluid needed to apply the friction elements are continuously updated for adaptive controls. As friction material wears, the volume of fluid need to apply the element increases. Certain mechanical problems within the input clutch assembly (broken return springs, out of position snap rings, excessive clutch pack clearance, improper assembly, etc.) can cause inadequate or out-of-range element volumes. Also, defective Input/Output Speed Sensors and wiring can cause these conditions. The following chart identifies the appropriate clutch volumes and when they are monitored/updated: SHIFT SCHEDULES As mentioned earlier, the TCM has programming that allows it to select a variety of shift schedules. Shift schedule selection is dependent on the following: -Shift lever position -Throttle position -Engine load -Fluid temperature -Software level As driving conditions change, the TCM appropriately adjusts the shift schedule. Refer to the following table 42RLE Shift Schedule to determine the appropriate operation expected, depending on driving conditions. 42RLE Shift Schedule
Final Drive Control Module - Installation3 steps
Fig. 1
Fig. 1
Fig. 2
Fig. 2
  1. Connect the two electrical connectors (1) into the FDCM.
  2. Install the FDCM being certain the locking tabs (1) are secure.
  3. Raise the drivers side knee bolster.
Final Drive Control Module - Removal3 steps
ℹ NOTE
The FDCM has two electrical connectors and is installed inside the passenger compartment behind the driver side knee bolster and is mounted to the left kick panel. On RHD vehicles the FDCM is located in a mirrored position on the right side.
Fig. 1
Fig. 1
Fig. 2
Fig. 2
  1. Lower the drivers side knee bolster.
  2. Push out on the two locking tabs (1) and remove the FDCM.
  3. Disconnect the two electrical connectors (1) from the FDCM.
Final Drive Control Module - Operationreference
ℹ NOTE
There is no requirement for the FDCM to distinguish between a neutral request from the 4WD AUTO or the 4WD LOW position. Resistances in these ranges will be represented as a Neutral Switch Activation.
OPERATION During normal operation of an active transfer case the FDCM control module learns and remembers the Clutch Engagement Point (Kiss Point), the position in the motor actuator's travel where torque begins to be transferred to the front wheels. The position is read out using the encoder as a 0 to 5 volt signal. This information is written into the module's EEPROM area at Ignition OFF. Over time the clutch pack wears and the Kiss Point changes in one direction (going from a lower voltage to a higher value). POWER UP/DOWN The Final Drive Control Module (FDCM) will power up with an OFF/ON transition of the hard wired ignition switch input. The FDCM will power down when the vehicle ignition switch transitions from ON to OFF or there are no system requirements that dictate the controller to remain active START-UP DIAGNOSTICS When the FDCM is activated, the internal circuitry will undergo a diagnostic procedure. The controller will examine all inputs and outputs for short circuits to ground, short circuits to battery and open circuits and will also verify proper CPU and memory operation. If a fault is detected, a message will be sent out over the CAN C bus to the Cluster indicating that service is recommended. After passing all diagnostic tests, the controller will receive and process inputs and produce the appropriate outputs. Proper monitoring of the controller inputs and outputs performance will continue. INPUTS/OUTPUTS The following are inputs to the FDCM: -Transfer Case Mode Sensor Signal -1 Direct Battery Feeds -Ignition RUN Sense -Sensor Ground -Module Ground -CAN C Bus The following are outputs of the FDCM: -Transfer Case Motor Brake Control (3022 only) -5V Sensor Supply -Transfer Case Bi-directional Motor Control (A AND B) -Switched B+ Solenoid Supply -Transfer Case Motor Brake Control TRANSFER CASE RANGE SELECT SWITCH INPUT (NEUTRAL, 2WD, 4WD AUTO and 4WD LOW SELECT SWITCH) The transfer case range select switch is hardwired directly to the Cluster (CCN). The switch position is read by the CCN and is communicated to the TIPM (Gateway) via the CAN-I bus. The TIPM then rebroadcasts this information onto the CAN-C bus where the FDCM is a receiver. The Cluster (CCN) will support circuitry which interfaces to the system's Transfer Case Range Select Switch, including a Transfer Case Range Select Switch voltage supply and a Transfer Case Range Select Switch input. The purpose of this circuitry is to determine the mode currently being requested by the operator via the resistance ladder network in the shifter assembly, where the Transfer Case Range Select Switch is packaged. The NEUTRAL Select Switch Input will provide the operator with the ability to place the Transfer Case in Neutral. The Select Switch Input will provide the operator with the ability to place the transfer case in 2WD, 4WD AUTO and 4WD LOW. The NEUTRAL Select Switch is a momentary pushpin switch and the 2WD, 4WD AUTO and 4WD LOW Select Switch is a 3-position toggle or a contact switch and both these switches are provided through a resistor network for diagnostic purposes. The input will have an internal 1.0K +/- 1% pull-up resistor to 5V. As the selected position in the switch varies and/or the NEUTRAL Switch is depressed or not, the resistance between the Cluster (CCN) voltage supply and Transfer Case Range Select Switches input will vary. Hardware, software, and calibrations within the Cluster will be provided that interpret the external resistance between the module's Transfer Case Range Select Switches voltage supply and Transfer Case Range Select Switches inputs as given in the table below: TRANSFER CASE MODE SENSOR SIGNAL The Transfer Case Mode Sensor Signal Input will provide the FDCM feedback about the position of the transfer case. The mode sensor will be a linear analog position sensor with a 1.4K +/- 20% potentiometer and a 1 K +/- 20% wiper resistor that converts the motor shaft position into a multiplexed voltage. The mode sensor (on the 3022 transfer case) is an active device where the sensor's current changes as the motor shaft position changes TRANSFER CASE BI-DIRECTIONAL MOTOR CONTROL (A AND B) This output will control a Bi-directional DC motor that controls a clutch pack in the Transfer Case that varies the torque transfer between the front and rear axles. MODES OF OPERATION Normal Operation This mode is achieved by the ignition being switched in the RUN position, which powers up the 5V regulator and generates the appropriate RESET for the microprocessor. This mode also includes any required power-up system checks. Shut Down Mode This mode is activated when the ignition switch turned to the off position. The FDCM will perform any required Shut Down tasks prior to turning off the 5V regulator. Limp-In Mode This mode is entered when the FDCM has detected an error condition that prevents the system from performing its' required task. The FDCM operation will vary depending from modified operation to total system shut down based on the failure that has occurred.
Final Drive Control Module - Descriptionreference
Fig. 1
Fig. 1
DESCRIPTION The Final Drive Control Module (FDCM) is a microprocessor-based assembly controlling the Transfer Case. Communication is via the CAN serial bus. Inputs include user selectable 2WD and 4WD modes that include 2WD, 4WD AUTO, 4WD LOW and Neutral. The FDCM has two electrical connectors and is installed inside the passenger compartment behind the driver side knee bolster and is mounted to the left kick panel. On RHD vehicles the FDCM is located in a mirrored position on the right side.
TCM Quick Learnreference
TCM QUICK LEARN The quick learn procedure requires the use of the scan tool. This program allows the electronic transmission system to recalibrate itself. This will provide the proper transmission operation. The quick learn procedure should be performed if any of the following procedures are performed: -Transmission Assembly Replacement -Transmission Control Module Replacement -Solenoid Pack Replacement -Clutch Plate and/or Seal Replacement -Valve Body Replacement or Recondition To perform the Quick Learn Procedure, the following conditions must be met: -The brakes must be applied -The engine speed must be above 500 rpm -The throttle angle (TPS) must be less than three degrees -The shift lever position must stay in PARK until prompted to shift to overdrive -The shift lever position must stay in overdrive after the Shift to Overdrive prompt until the scan tool indicates the procedure is complete. -The calculated oil temperature must be above 16° C (60° F) and below 93° C (200° F).
TCM Drive Learn21 steps
ℹ NOTE
It is not necessary to perform the complete Drive Learn procedure every time the TCM is Quick Learned. Perform only the portions which target the objectionable shift.
ℹ NOTE
The transmission oil temperature must be between 27-43° C (80-110° F).
ℹ NOTE
It is important that this procedure be performed when the transmission temperature is between 27-43° C (80-110° F). If this procedure takes too long to complete fully for the allowed transmission oil temperature, the vehicle may be returned to the customer with an explanation that the shift will improve daily during normal vehicle usage. The TCM also learns at higher oil temperatures, but these values (line pressure correction values) are not available for viewing on the scan tool.
ℹ NOTE
The transmission oil temperature must be between 27-43° C (80-110° F) to learn the UD CVI. Additional learning occurs at temperatures as low as -18° C (0° F) and as high as 93° C (200° F). This procedure may be performed at any temperature that experiences poor shift quality. Although the UD CVI may not change, shift quality should improve.
ℹ NOTE
The transmission oil temperature must be above 27° C (80° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
ℹ NOTE
The transmission oil temperature must be above 43° C (110° F).
  1. Start the engine only when the engine and ignition have been off for at least ten (10) minutes.
  2. With the vehicle at a stop and the service brake applied, record the 1st N-D UD CVI while performing a Neutral to Drive shift. The 1st N-D UD CVI accounts for air entrapment in the UD clutch that may occur after the engine has been off for a period of time.
  3. Repeat 1 and 2 until the recorded 1st N-D UD CVI value stabilizes. LEARN A SMOOTH NEUTRAL TO DRIVE GARAGE SHIFT Perform this procedure if the complaint is for a delayed or harsh shift when the transmission is put into gear after the vehicle has had its first shift. Use the following steps to have the TCM learn the Norm N-D UD CVI.
  4. Start the vehicle engine and shift to drive.
  5. Move the vehicle forward to a speed of at least 16 km/h (10 MPH) and come to a stop. This ensures no air is present in the UD hydraulic circuit.
  6. Perform repeated N-D shifts at a stop while pausing in Neutral for at least 2-3 seconds and monitor Norm N-D UD CVI volume until the value stabilizes. The value will change during the N-D shift. This is normal since the UD value is different for the N-D shift then the normal value shown which is used for 4-3 coastdown and kickdowns. Perform repeated shifts in this temperature range until the Norm N-D UD CVI value stabilizes and the N-D shifts become smooth. LEARN THE 1ST 2-3 SHIFT AFTER A RESTART OR SHIFT TO REVERSE Use the following steps to have the TCM learn the 1st 2-3 shift OD CVI.
  7. With the vehicle engine running, select reverse gear for over 2 seconds.
  8. Shift the transmission to Drive and accelerate the vehicle from a stop at a steady 15 degree throttle opening and perform a 2-3 shift while noting the 1st 2-3 OD CVI.
  9. Repeat 1 and 2 until the 1st 2-3 upshift becomes smooth and the 1st 2-3 OD CVI stabilizes. LEARN A SMOOTH 2-3 AND 3-4 UPSHIFT Use the following steps to have the TCM learn the OD and 4C CVI's.
  10. Accelerate the vehicle from a stop at a steady 15 degree throttle opening and perform multiple 1-2, 2-3, and 3-4 upshifts. The 2nd 2-3 shift following a restart or shift to reverse will be shown during the shift as a value between the 1st 2-3 OD CVI and the normal OD CVI. Updates to the normal OD CVI will occur after the 2nd shift into 3rd gear, following a restart or shift to reverse.
  11. Repeat 1 until the 2-3 and 3-4 shifts become smooth and the OD and 4C CVI become stable. LEARN A SMOOTH 4-3 COASTDOWN AND PART THROTTLE 4-3 KICKDOWN Use the following steps to have the TCM learn the UD shift volume.
  12. At a vehicle speed between 64-97 km/h (40-60 mph), perform repeated 4-3 kickdown shifts.
  13. Repeat 1 until the UD volume becomes somewhat stable and the shift becomes smooth. LEARN A SMOOTH 1-2 UPSHIFT AND 3-2 KICKDOWN Use the following steps to have the TCM learn the 2C shift volume.
  14. With a vehicle speed below 48 km/h (30 mph) and the transmission in 3rd gear, perform multiple 3-2 kickdowns.
  15. Repeat 1 until the 3-2 kickdowns become smooth and the 2C CVI becomes stable. LEARN A SMOOTH MANUAL 2-1 PULLDOWN SHIFT AS WELL AS A NEUTRAL TO REVERSE SHIFT Use the following steps to have the TCM learn the LR volume.
  16. With the vehicle speed around 40-48 km/h (25-30 mph) in Manual 2nd, perform manual pulldowns to Low or 1st gear at closed throttle.
  17. Repeat 1 until the LR CVI becomes stable and the manual 2-1 becomes smooth. LEARN A SMOOTH NEUTRAL TO REVERSE SHIFT
  18. With the vehicle at a stop, perform Neutral to Reverse shifts until the shift is smooth. An unlearned Neutral to Reverse shift may be harsh or exhibit a double bump.
  19. If any of the shifts are still not smooth after the clutch volume stabilizes, an internal transmission problem may be present. LEARN A SMOOTH 4-5 UPSHIFT Use the following steps to have the TCM learn the Alt 2C CVI.
  20. Accelerate the vehicle through 88 km/h (55 mph) at a steady 10-15 degree throttle opening and perform multiple 4-5 upshifts.
  21. Repeat 1 until the 4-5 shift become smooth and the Alt 2C CVI become stable. There is a separate 2C volume used and learned for 4-5 shifts, 2CA. It is independent of the 2C CVI learned on 3-2 kickdowns.
Transmission Control Module - Descriptionreference
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TRANSMISSION CONTROL MODULE - GASOLINE ENGINES The Transmission Control Module (TCM) is a sub-module within the Powertrain Control Module (PCM) (1). The PCM is located on the right inner fender. The NGC IV (fourth-generation) Powertrain Control Module (PCM) provides integrated electronic control of all transmission functions. If the vehicle is equipped with a NAG1 transmission the TCM (1) is a separate module located behind the drivers knee bolster to the right of the steering column.
Transmission Control Module - Operationreference
ℹ NOTE
If the TCM has been replaced, the "Quick Learn Procedure" must be performed.
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TRANSMISSION CONTROL MODULE - GASOLINE ENGINES The TCM is the controlling unit for all electronic operations of the transmission. The TCM receives information regarding vehicle operation from both direct and indirect inputs, and selects the operational mode of the transmission. Direct inputs are hard-wired to, and used specifically by the TCM. Indirect inputs originate from other components/modules, and are shared with the TCM via the CAN bus. Some examples of direct inputs to the TCM are: -Battery (B+) voltage -Ignition "ON" voltage -Transmission Control Relay (Switched B+) -Throttle Position Sensor -Crankshaft Position sensor (CKP) -Transmission Range Sensor (TRS) -Pressure Switches (L/R, 2/4, OD) -Transmission Temperature Sensor (TTS) (Integral to TRS) -Input Shaft Speed Sensor -Output Shaft Speed Sensor Some examples of indirect inputs to the TCM are: -Engine/Body Identification -Manifold Pressure -Target Idle -Torque Reduction Confirmation -Speed Control ON/OFF Switch -Engine Coolant Temperature -Ambient/Battery Temperature -Brake Switch Status -Scan Tool Communication Based on the information received from these various inputs, the TCM determines the appropriate shift schedule and shift points, depending on the present operating conditions and driver demand. This is possible through the control of various direct and indirect outputs. Some examples of TCM direct outputs are: -Transmission Control Relay -Solenoids (L/R, 2/4, OD and UD) -Vehicle Speed (to PCM) -Torque Reduction Request (to PCM) Some examples of TCM indirect outputs are: -Transmission Temperature (to PCM) -PRNDL Position (to CCN) In addition to monitoring inputs and controlling outputs, the TCM has other important responsibilities and functions: -Storing and maintaining Clutch Volume Indices (CVI) -Storing and selecting appropriate Shift Schedules -System self-diagnostics -Diagnostic capabilities (with scan tool) TCM Quick Learn CLUTCH VOLUME INDEX (CVI) An important function of the TCM is to monitor Clutch Volume Index (CVI). CVIs represent the volume of fluid needed to compress a clutch pack. The TCM monitors gear ratio changes by monitoring the Input and Output Speed Sensors. The Input, or Turbine Speed Sensor sends an electrical signal to the TCM that represents input shaft rpm. The Output Speed Sensor provides the TCM with output shaft speed information. By comparing the two inputs, the TCM can determine transmission gear position. This is important to the CVI calculation because the TCM determines CVIs by monitoring how long it takes for a gear change to occur Gear ratios can be determined by using the scan tool and reading the Input/Output Speed Sensor values in the "Monitors" display. Gear ratio can be obtained by dividing the Input Speed Sensor value by the Output Speed Sensor value. For example, if the input shaft is rotating at 1000 rpm and the output shaft is rotating at 500 rpm, then the TCM can determine that the gear ratio is 2:1. In direct drive (3rd gear), the gear ratio changes to 1:1. The gear ratio changes as clutches are applied and released. By monitoring the length of time it takes for the gear ratio to change following a shift request, the TCM can determine the volume of fluid used to apply or release a friction element. The volume of transmission fluid needed to apply the friction elements are continuously updated for adaptive controls. As friction material wears, the volume of fluid need to apply the element increases. Certain mechanical problems within the input clutch assembly (broken return springs, out of position snap rings, excessive clutch pack clearance, improper assembly, etc.) can cause inadequate or out-of-range element volumes. Also, defective Input/Output Speed Sensors and wiring can cause these conditions. The following chart identifies the appropriate clutch volumes and when they are monitored/updated: SHIFT SCHEDULES As mentioned earlier, the TCM has programming that allows it to select a variety of shift schedules. Shift schedule selection is dependent on the following: -Shift lever position -Throttle position -Engine load -Fluid temperature -Software level As driving conditions change, the TCM appropriately adjusts the shift schedule. Refer to the following table 42RLE Shift Schedule to determine the appropriate operation expected, depending on driving conditions. 42RLE Shift Schedule