Circuit Description
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Trim B solenoid is used to control oncoming, off-going, and holding pressure to any one of the five clutches. This solenoid is referred to as a pressure proportional to current (PPC) solenoid since the output hydraulic pressure supplied by this solenoid is proportional to the controlled current command.
The transmission control module (TCM) uses information from the turbine and output speed sensors to detect if a clutch is in a tie-up condition or 3 clutches are applied. The clutch being controlled by B solenoid will vary depending on the shift being made.
DTC P0777 is a type A DTC.