Diagnostic Aids
WARNING: This page is about a different car, the 2020 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.
- High resistance in the circuits of the component may set DTC P18AD without setting the DTC for the component : Q77D Transmission Control Solenoid Valve 4
- If fluid pressure is less than 345 kPa (50 PSI), DTC P18AB & P18AD may set. - Refer to : Line Pressure Check