Repair Instructions
WARNING: This page is about a different car, the 2023 GMC Sierra 3500 HD and 2023 GMC Sierra 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification
- Q77 Transmission Control Solenoid Valve Characterization Programming (10L1000)
- Automatic Transmission Fluid, Fluid Pan and/or Filter Replacement
- Automatic Transmission Wiring Harness Replacement
- Control Valve Assembly and Transmission Wiring Harness Installation - Q77A Transmission Control Solenoid Valve 1
- Control Valve Assembly and Transmission Wiring Harness Removal - Q77A Transmission Control Solenoid Valve 1
- For control module replacement, programming, and setup refer to: Control Module References
Additional Procedures
Transmission Service Fast Learn Procedure - Perform only when the component/system is serviced.