When a transmission solenoid has malfunctioned, in most cases the problem is not the electrical part of the solenoid; the problem is foreign material obstructing the mechanical function of the solenoid or the flow of the fluid through the transmission valve body. If the transmission fluid is dirty, it's recommended to change the transmission fluid and if possible, remove the transmission pan for further diagnosis. Excessive debris or metal particles on the transmission pan could be an indication that there is a mechanical transmission failure, and that the transmission will need to be rebuilt or replaced.
There is a factory service bulletin for the following GMC Models:
2007-2009 GMC Acadia
2007-2009 GMC Acadia Factory Service Bulletin OBDII Code P0777
Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
The cost to diagnose the P0777 GMC code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.
The clutch pressure control solenoid valve 2 is part of the control solenoid valve assembly, which has no serviceable parts. The pressure control solenoid valve 2 regulates transmission fluid pressure to the 3-5-Reverse clutch regulator valve which controls pressure to the 3-5-Reverse clutch. The Transmission Control Module calculates the gear ratio based on the RPM signals from the input speed sensor (ISS) and the output speed sensor (OSS). The Transmission Control Module compares the expected transmission gear ratio to the calculated gear ratio for each commanded gear. The Diagnostic Trouble Code (DTC) will be set when the Transmission Control Module has detected an incorrect gear ratio change when the 3-5-R clutch is commanded OFF during a shift or when 3rd gear ratio is detected in 1st gear. This condition must occur 3 times.
Need more information on how to fix the P0777 GMC code? Get Access to Factory Service Manuals
Get the P0777 GMC code diagnosed by a professional: Find a repair shop in your area