Diagnostic Fault Information

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:

DTC P2820 will set with a hydraulic/mechanical condition.
The components are listed from the least to the most intrusive to service.
Verify the conditions listed in the table do not exist

Component	DTC	Condition
Q77J Transmission Control Solenoid Valve 9	P2820	Retaining Clip Missing Visible Damage Solenoid Valve Binding or Sticking Mechanically damaged Stuck
Default Disable Valve Valve Body Bore Valve Spring	P2820	Bore Debris on the component. Scored Valve Binding or Sticking Debris on the component. Mechanically damaged Scored Stuck Valve Spring Visible Damage
Default Select Valve Valve Body Bore Valve Spring	P2820	Valve Binding or Sticking Debris on the component. Scored Stuck Mechanically damaged Bore Scored Debris on the component. Valve Spring Visible Damage
Control Valve Body	P2820	Fluid/oil passage Leaking Restricted