Diagnostic Test
- CHECK FOR CAN BUS DTCS
- With the scan tool, check for CAN BUS DTCs.
Are there any CAN BUS DTCs present?
Yes
- Refer to the DTC INDEX article and perform the appropriate diagnostic procedure.
- Perform the NAG1 TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .
No
- Go To 2
- With the scan tool, check for CAN BUS DTCs.
- CHECK IF ENGINE DTCS ARE PRESENT
- With the scan tool, read engine DTCs.
Are there any engine DTCs present?
Yes
- Refer to the DTC INDEX article and perform the appropriate diagnostic procedure.
- Perform the NAG1 TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .
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 and program the TCM in accordance with the Service Information. Refer to MODULE, TRANSMISSION CONTROL, REMOVAL .
- Perform the NAG1 TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .
- With the scan tool, read engine DTCs.