NAG1

U0423-IMPLAUSIBLE DATA RECEIVED FROM CLUSTER/CCN





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 CLUSTER/CCN.

Possible Causes
CAN BUS DTC'S PRESENT
CLUSTER/CCN MODULE DTC'S PRESENT
TRANSMISSION CONTROL MODULE

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test
1. CHECK FOR FCM CAN BUS DTCS
With the scan tool, read FCM DTCs.
Are there any FCM CAN BUS DTCs present?
Yes >>Refer to Body Control System.
Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test
No >>Go To 2

2. CHECK IF CLUSTER/CCN DTCS ARE PRESENT
With the scan tool, read CLUSTER/CCN DTCs.
Are there any CLUSTER/CCN DTCs present?
Yes >>Refer to INSTRUMENT CLUSTER - TESTING and perform the appropriate symptom.
Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test
No >>Using the schematics as a guide, check the Transmission Control Module (TCM) pins, terminals, and connectors 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. Transmission Verification Test