LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Jeep >> 2023 >> Gladiator Freedom, Part Time T/Case Control >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Collision/Avoidance >> Electronic Control Modules (Service Information) >> Module, Drivetrain Control (DTCM) >> Description And Operation
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Description And Operation

DESCRIPTION 

GC0192951Courtesy of CHRYSLER GROUP, LLC
1 - DTCM

The Drivetrain Control Module (DTCM) is located on the rear cabin wall. The DTCM communicates with the vehicle systems through the Controller Area Network - Chassis (CAN-C) bus to optimize the performance of the vehicles All Wheel Drive (AWD) functionality.

The DTCM is powered by the front Power Distribution Center (PDC).

OPERATION 

DTCM and the Transfer Case status: 

The DTCM monitors the state of the transfer case and reports the current operating mode, mode shift, and range to the vehicle over the CAN-C data bus.

A mode shift is defined as a shift between any of following transfer case states:

If the DTCM receives a request to perform a mode shift from 2WD into either of the 4WD modes, the DTCM will verify that the wheel speeds are within an acceptable range prior to engaging the Front Axle Disconnect (FAD).

DTCM interaction with the Powertrain Control Module (PCM): 

To improve range shifts beginning in 4LO, the PCM needs to raise idle speed when shifting out of 4LO. The Powertrain Control Module (PCM) will perform the following procedure:

If the above conditions are true, the PCM will monitor for a DTCM status signal over the bus for a change of state from 4LO. Once the change of state has occurred, the PCM will raise engine idle speed target to the calibrated value. The PCM will cancel the idle increase when the transfer case completes its shift.

DTCM and Transfer Case Clutch Torque Control 

The DTCM provides the amount of torque currently being transferred across the transfer case clutch using CAN-C data signals. If the transfer case torque cannot be determined due to sensor failure or other system failures, the DTCM will set an internal Diagnostic Trouble Code (DTC).

Slip Correction - The DTCM will transfer torque to the front wheels upon wheel slip. Wheel slip threshold is calibratable and will be different for each mode. Wheel slip is calculated by the DTCM by using the available wheel speed sensor messages on the vehicle CAN-C bus from the Antilock Brake System (ABS) module. The wheel speed sensor data signals include each individual wheels Revolution Per Minute (RPM) values.

Over/Under steer control - Yaw Event (under and over steer): The DTCM continuously monitors vehicle yaw versus the vehicle intended path (yaw error) and transfers the appropriate level of torque to correct the yaw error. The level of yaw correction is calibratable and may be different for each mode.

The DTCM uses the following signals from the ABS module to determine vehicle over/under steer dynamics:

The DTCM and Front Axle Disconnect Triggers - Wheel Slip:

The DTCM uses these signals from the ABS module to calculate difference in wheel speeds when equipped with the front axle disconnect:

If the difference in wheel speeds is greater than a calibratable value of 32 km/h (16 mph), the DTCM automatically engages the 4WD system to provide the best possible traction.

DTCM and Incoming Torque Requests -  For vehicles equipped with an active transfer case, the DTCM will perform the following requirements:

If Electronic Stability Control (ESC) torque requests are received, the DTCM will command the transfer case clutch to fully open.

If ESC Torque Mode Request Feedbacks are received, the DTCM will provide feedback to the ABS module regarding the DTCM operation mode. This allows the ABS modules ESC function to determine if the DTCM is responding to the ESC request.

DTCM Outgoing Torque Requests -  Engine Torque Reduction:

The DTCM All Wheel Drive (AWD) controller can request an effective flywheel torque over the CAN-C network as a limit under specific conditions that can harm the driveline. The AWD system has a thermal model in the DTCM. When the DTCM detects a possible overheat condition, it will temporarily request reduced torque from the PCM. The DTCM will continuously send out a constant value torque reduction request until the AWD system no longer needs thermal protection.

The PCM receives the AWD torque request and will then need to verify the request as valid. The DTCM will only send out a torque demand and an actual flywheel torque request. This torque request is treated as a minimum mode torque request. The minimum mode takes the minimum of driver demand, electronic stability torque, acceleration torque and AWD torque to be used for torque calculations.

When the PCM receives the DTCM torque request, it compares the request with an internal calibration limit. If the request is less than this limit value, the request will not be honored. Otherwise, the DTCM torque request is valid and the torque reduction request will be used with ramp in and ramp out rates that limit how quickly the torque can change. Both the ramp in rate and the ramp out rate will use separate calibrations. There is also a calibrated timer limit for how long the active request is to be considered valid.

The DTCM calculates and transmits a Cyclical Redundancy Check (CRC) and a message counter with each transmission message regardless of the presence of an active DTCM torque request. The PCM receives the entire message and compares the received CRC and message counter to its own expected values to verify the validity of the received message. If either of these checks fail, the PCM will deny the torque request and set the appropriate DTC for implausible data.

Rotary Switch output to the DTCM  The BCM interfaces with the Drive/Terrain rotary mode switch. This feature applies to vehicles equipped with Customer Selectable Transmission Drive Modes. When the vehicle is equipped with these features (for example, Transmission Drive Modes) the user will have the rotary Drive/Terrain mode switch to make the desired selection. The user will be able to select any Drive Mode from the available options when the ignition status is in the run/start position, regardless of engine state. The BCM, will keep the request active for the entire time the mode is requested as an output to the DTCM.

DTCM Indication Management of the Transfer Case Status to the Instrument Panel Cluster (IPC) 

The DTCM determines and sends the transfer case position status messages over the bus network for the IPC to display. For the part time transfer case, the DTCM sends the following transfer case status messages:

For the Full time Transfer Case, the DTCM sends the following transfer case status messages:

When the vehicle is equipped with an automatic transmission, the DTCM will also broadcast the "Neutral Shifter Position Warning" as needed.

DTCM IPC Indication Requirements: 

The DTCM sends a specific CAN-C messages to the IPC which is used by the IPC in identifying appropriate message or series of messages to be displayed to the driver.

The IPC will use above DTCM status message to indicate the transfer case state and display this to the driver.

Service 4WD IPC Indication -The DTCM will request the "Service 4WD" tell-tale via a CAN-C signal when any of the following conditions are true:

.

The IPC enables its own internal logic to display the message when commanded.

If a DTC is stored or active that results in no functionality or a level of decreased functionality exists that a customer should be notified of, the IPC will display messages to the driver indicative of the experienced condition. The following table covers some of the messages shown on the IPC:

MESSAGE EXPLANATION POTENTIAL CAUSES
4WD System Temporarily Unavailable IPC message informing driver of generic fault of 4WD system Loss of communication with other modules or a low tire pressure condition
4WD Neutral Warning Vehicle May Move Even in Park This is a transfer case in N  eutral warning
Service 4WD System Service Required Message The message will timeout, but the Light Emitting Diode (LED) indicator on IPC will stay illuminated
Mismatched Tire Size 4WD Reduced Performance Spare Tire Detected This message displays for calibratable time period when module software detects mini spare is in use
4WD Overheated Temporarily Unavailable Actuator Over Temp This message displays for calibratable time period when the actuator is over temp and a request is shown to the customer to perform a range shift or the neutral shift
4WD Overheated Performance Temporarily Reduced Clutch Over Temp Used to inform the driver that 4WD Auto is not currently available due to a clutch over heat condition
     
This table is not intended to replace diagnostic methods. Normal diagnostic methods should still be followed. 

Locker Management ASBM> <BCM> <DTCM 

The Auxiliary Switch Bank Module (ASBM) is the interface between the driver and the Electronic Locker management system. The ASBM reads two inputs:

ASBM Switch 1: Driver selection of which axle locker should be engaged. This switch is read using button pressed or button not pressed logic. This switch is a three position mono-stable toggle switch that has the following positions:

ASBM Switch 2: Driver selection to disengage ALL axle lockers. This switch is also read using button pressed or button not pressed logic and it has the following 2 positions:

The BCM gates signals for the ASBM between the Local Interior Network (LIN) bus and the CAN-C bus. The DTCM receives the request from the BCM over the CAN-C network bus to engage the axle lockers. The DTCM evaluates the interlocks to determine if conditions are met to lock the axles. If conditions are met to lock the axles, the DTCM attempts to lock the front or rear axle. If conditions are not met to lock axles, the DTCM will do one of the following depending on the type of request and the current vehicle conditions:

The BCM receives DTCM output CAN-C messages containing ASBM switch LED illumination requests. The BCM gates these DTCM CAN-C messages to LIN message request and then sends these message requests to the ASBM to illuminate the appropriate switch based on the message received, front or rear.

DTCM and the Axle Locker Functionality 

The DTCM receives the gated ASBM ON or OFF signals to request front and rear axle locker engagement as well as the disengagement requests from the customer.

If the DTCM determines that a valid request to engage axle lockers has been made, the DTCM evaluates the engagement interlocks. If all axle locker engagement interlocks are satisfied, the DTCM will attempt to lock the desired axle(s). If all axle locker engagement interlocks are not satisfied, the DTCM will send data bus messages to the IPC to display to the driver which conditions must be satisfied prior to an attempt to locking the desired axle(s) can be made.

The DTCM also sends a CAN-C message to the IPC to request a "Service Axle Locker System" message be displayed to the driver. Any time there is a DTC set in the axle locker system, this message will display to the customer. Conditions such as loss of communication or other mechanical or electrical functional axle locker component issues can set a DTC.

DTCM and the Rear Axle Locker 

When the DTCM receives a request to lock the rear axle, each of the following interlocks must  be satisfied before attempting a locking event:

DTCM and the Front Axle Locker 

When the DTCM receives a request to lock both front and Rear axles, each of the following interlocks must  be satisfied before attempting a locking event

DTCM and the Auto-Locker Functionality  - The DTCM is capable of automatically engaging or disengaging axle lockers.

Automatic locker disengage involving the transfer case range:

Automatic locker disengage involving the ignition position:

Automatic locker disengage involving a locked rear axle locker AND the vehicle is equipped with a front axle locker:

If the front axle locker is engaged, and the rear axle locker state changes from LOCKED to UNLOCKED, the DTCM will automatically disengage the front axle locker

scientia non olet · About LEMON Manuals