Transmission Control Module (TCM)

U0431-IMPLAUSIBLE DATA FROM FCM/TIPM



Theory of Operation

The messages sent on the CAN bus are distinguished by an identifier (ID). Each CAN ID is defined to contain a certain number of bytes. The Transmission Control Module (TCM) verifies that it has received the proper number of bytes for each ID.

- When Monitored:
Continuously with the ignition on, one valid CAN ID received at least once, and no U0002-CAN Bus Off Performance DTC present.

- Set Condition:
When the TCM detects an incorrect CAN ID from the TIPM/FCM.





Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. NAG1 Pre-Diagnostic Troubleshooting Procedure.
CHECK FOR TIPM/FCM CAN BUS DTCS
1. With the scan tool, read TIPM/FCM DTCs.

Are there any TIPM/FCM CAN BUS DTCS present?

Yes

- Perform the NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test.

No

- Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the TCM.
- Perform the NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test.