Transmission Control Module (TCM) - NAG1

P0601-INTERNAL MEMORY CHECKSUM INVALID

For a complete wiring diagram, refer to the Wiring Information.

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 a DTC will set.

- 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 NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. NAG1 Pre-Diagnostic Troubleshooting Procedure.
CHECK IF TCM IS FLASHABLE

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

1. With the scan tool, record the vehicles controller part number.
2. Select Use Controller Part Number under the Flash Tab.
3. Flash the controller with the correct software.

Were you able to update (flash) the controller successfully?

Yes

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

No

- Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the TCM.
- Perform the NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test.