Circuit/System Verification

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.

NOTE:

This procedure is required when the following component has been repaired, replaced, removed, or serviced:

Control Valve Body
K71 Transmission Control Module
T12 Automatic Transmission Assembly
Q77 Transmission Control Solenoid Valve

Ignition - On/Vehicle - In Service Mode
Verify DTC P27A7, P27A8, P27A9, P27AA, P27AB, P27AC, P27AD, P27AE is not set.
- If any of the DTCs are set
  Refer to:Q77 Transmission Control Solenoid Valve Characterization Programming (10L1000)
- Go to next step: If no DTC is set
All OK.