U1439

U1439-IMPLAUSIBLE/MISSING PROGRAMMED AXLE RATIO

For a complete wiring diagram Refer to Diagrams/Electrical.

Theory of Operation


This programmed axle ratio information is received from the TIPM to be used by the TCM as part of speed sensor diagnostics.


When Monitored:
- Continuously with the key-on.


Set Condition:
- This fault is set when any other values other than 4.88, 4.44, 4.10, or 3.73 is received, or the message is not received for more than 10.5 seconds.







Always perform the AS68RC Pre-Diagnostic Troubleshooting procedure before proceeding. AS68RC - Pre-Diagnostic Troubleshooting Procedure


Diagnostic Test


1. CHECK FOR TIPM CAN BUS DTCS
With the scan tool, read TIPM DTCs.
Are there any TIPM CAN BUS DTCs present?

Yes


- Repair the DTC(s).
- Perform AS68RC VERIFICATION TEST. AS68RC Transmission Verification Test


No


- Go To 2



2. CHECK IF ENGINE DTCS ARE PRESENT
With the scan tool, read engine DTCs.
Are there any engine DTCs present?

Yes


- Repair the DTC(s).
- Perform AS68RC VERIFICATION TEST. AS68RC 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 AS68RC VERIFICATION TEST. AS68RC Transmission Verification Test