2007 Grand Cherokee WK Factory Service Manual 21 - TRANSMISSION AND TRANSFER CASE

U0423-IMPLAUSIBLE DATA RECEIVED FROM CLUSTER/CCN

For a complete wiring diagram Refer to Section 8W

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.



Possible Causes
 
CAN BUS DTCS PRESENT
 
CLUSTER/CCN MODULE DTCS PRESENT
 
TRANSMISSION CONTROL MODULE
 


Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)



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


No

2. CHECK IF CLUSTER/CCN DTCS ARE PRESENT

With the scan tool, read CLUSTER/CCN DTCs.

Are there any CLUSTER/CCN DTCs present?

Yes


No