U1440

U1440-IMPLAUSIBLE/MISSING PROGRAMMED TRANSFER CASE HI RATIO

For a complete wiring diagram refer to the Wiring Information Electrical Diagrams.

Theory of Operation

This programmed Transfer Case Hi 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 1.0 is received, or the message is not received for more than 10.5 seconds.






Always perform the AS68RC Pre-Diagnostic Troubleshooting procedure before proceeding. Testing and Inspection

1. CHECK FOR TIPM CAN BUS DTCS
1. With the scan tool, read TIPM DTCs.

Are there any TIPM CAN BUS DTCs present?

Yes

- Perform the appropriate test(s).
- Perform AS68RC TRANSMISSION VERIFICATION TEST. AS68RC Transmission Verification Test

No

- Go To 2

2. CHECK IF ENGINE DTCS ARE PRESENT
1. With the scan tool, read engine DTCs.

Are there any engine DTCs present?

Yes

- Perform the appropriate test(s).
- Perform AS68RC TRANSMISSION 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 TRANSMISSION VERIFICATION TEST. AS68RC Transmission Verification Test