U140A

U140A-IMPLAUSIBLE RIGHT FRONT WHEEL SPEED SIGNAL RECEIVED





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.

Possible Causes
- FCM CAN BUS DTC S PRESENT
- ABS CONTROL MODULE DTC S PRESENT
- TRANSMISSION CONTROL MODULE

Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. Component Tests and General Diagnostics

Diagnostic Test
1. CHECK FOR FCM CAN BUS DTC's
With the scan tool, read FCM DTC's.
Are there any FCM CAN BUS DTC's present?
YES >>Refer to appropriate diagnostic test.
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 DTC's.
Are there any ABS DTC's present?
YES >>Refer to 5 - BRAKES - ABS ELECTRICAL DIAGNOSTICS category and perform the appropriate symptom.
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.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1. Transmission Verification Test