U1409

U1409-IMPLAUSIBLE LEFT FRONT WHEEL SPEED SIGNAL RECEIVED

For a complete wiring diagram consult Diagrams/Electrical

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 ABS control module.







Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. Testing and Inspection


Diagnostic Test


1. CHECK FOR FCM CAN BUS DTCS
With the scan tool, read FCM DTCs.
Are there any FCM CAN BUS DTC's present?

Yes


- Diagnose and repair the DTC(s).
- Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1. Transmission Verification Test


No


- Go To 2




2. CHECK IF ABS DTC'S ARE PRESENT
With the scan tool, read ABS DTCs.
Are there any ABS DTC's present?

Yes


- Diagnose and repair the DTC(s).
- Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1. 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. Transmission Control Module - Description
- Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1. Transmission Verification Test