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
1. Refer to ELECTRONIC CONTROL MODULES - ELECTRICAL DIAGNOSTICS and perform the appropriate symptom.
2. Perform NAG1 TRANSMISSION VERIFICATION TEST .
No
1. Go To 2).
2) CHECK IF HVAC DTCS ARE PRESENT
With the scan tool, read HVAC DTCs.

Are there any HVAC DTCs present?

Yes
1. Refer to DIAGNOSTIC CODE INDEX and perform the appropriate symptom.
2. Perform NAG1 TRANSMISSION VERIFICATION TEST .
No
1. 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 and program the TCM. Refer to MODULE - TRANSMISSION CONTROL .
2. Perform NAG1 TRANSMISSION VERIFICATION TEST .