AutoCodes – GMC – P0777 GMC

P0777 GMC Code - Clutch Pressure Control Solenoid 2 Stuck On

Quick Answer

The clutch pressure control solenoid valve 2 is part of the control solenoid valve assembly, which has no serviceable parts. Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Control Solenoid Valve Assembly. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0777 GMC indicates Clutch Pressure Control Solenoid 2 Stuck On.
Common causes: Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Control Solenoid Valve Assembly.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 9,440

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 25, 2024

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P0777 GMC Description

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.

OBDII Code P0777 GMC - Clutch Pressure Control Solenoid 2 Stuck On - AutoCodes.com — P0777 GMC Code - Clutch Pressure Control Solenoid 2 Stuck On

What does this mean?

What are the Possible Causes of the DTC P0777 GMC?

Low transmission fluid level
Dirty transmission fluid
Faulty Control Solenoid Valve Assembly
Control Solenoid Valve Assembly harness or connectors
Control Solenoid Valve Assembly circuit is open or shorted

How to Fix the DTC P0777 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

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

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0777 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0777 GMC code?

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Information for Specific GMC Models

P0777 2014 GMC Sierra — Clutch Pressure Control Solenoid 2 Stuck On
P0777 2015 GMC Sierra — Clutch Pressure Control Solenoid 2 Stuck On
P0777 2016 GMC Sierra — Clutch Pressure Control Solenoid 2 Stuck On
P0777 2017 GMC Sierra — Clutch Pressure Control Solenoid 2 Stuck On
P0777 2018 GMC Sierra — Clutch Pressure Control Solenoid 2 Stuck On

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0777 GMC Code

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Mike
Date: January 31, 2017 at 5:14 pm

I have a '07 Acadia with 140 k miles, I had the transmission fluid exchange service on it. After service I could hear a high pitched sound in first gear.200 miles later it began to slip and 300 miles later transmission went completely out.It know shows PO 777 and P2723 codes. I know GMC has extened the warranty on this particular transmission. What do you think caused the transmission to go out? Something with the fluid
Exchange or just a coenicidence.

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