P1644

P1644-INCORRECT VARIANT/CONFIGURATION







Theory of Operation

The Transmission Control Module (TCM) performs various internal tests to verify proper controller operation. If the TCM detects that the variables that dictate the vehicle application are not present, the controller will enter Limp-in mode and illuminate the MIL.

- When Monitored:
Continuously with the ignition on.

- Set Condition:
If the TCM detects that the variables that dictate the vehicle application are not present.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. . Testing and Inspection
PERFORM TCM REPLACEMENT PROCEDURE

NOTE: Controller is programmed with generic software and will not allow the correct vehicle Powertrain management.

1. With the scan tool, perform the TCM replacement procedure.

Were you able to update the controller successfully?

Yes

- Test Complete.
- Perform the NAG1 TRANSMISSION VERIFICATION TEST. NAG1 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 the NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test.