Normal Operation and Fault Conditions

Vehicles equipped with an automatic transmission (except those equipped with a 3.5L GTDI engine) have a stand-alone TCM. On vehicles equipped with a 3.5L GTDI engine, the TCM is an internal component of the PCM. With the ignition ON, the TCM sends messages to the GWM over the HS-CAN1, the GWM relays these messages to the ABS module over the HS-CAN2. If the ABS module does not receive these messages within the specified time frame, the ABS module sets DTCs. This can be due to a TCM failure, a circuit failure on the HS-CAN or an excessive load on the network. For information on the messages sent to the ABS module by the TCM, refer to the Network Message Chart in Description and Operation of the Anti-Lock Brake System (ABS) and Stability Control article.

PPT I ABS MODULE DTC FAULT TRIGGER CONDITIONS

DTC	Description	Fault Trigger Condition
U0101:00	Lost Communication With TCM: No Sub Type Information	Sets when the ABS module does not receive any transmission messages from the PCM.
U0402:00	Invalid Data Received From TCM: No Sub Type Information	Sets when the ABS module detects the transmission gear position or transmission gear lever (PRNDL) position message is "invalid" instead of the actual gear or gear lever position.