AutoCodes – GMC – P0797 2018 GMC Sierra

P0797 2018 GMC Sierra Code - Pressure Control Solenoid Valve 3 Stuck On

Quick Answer

The clutch pressure control solenoid 3 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
P0797 2018 GMC Sierra indicates Pressure Control Solenoid Valve 3 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 264
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Mar 25, 2024
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Code P0797 2018 GMC Sierra Description

The clutch pressure control solenoid 3 is part of the control solenoid valve assembly, which has no serviceable parts. The Clutch Pressure Control Solenoid 3 regulates transmission fluid pressure to the CBR1/C 4-5-6 clutch regulator valve which controls pressure to the low/reverse clutch and the 4-5-6 clutch. The Transmission Control Module calculates 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 low and reverse clutch and the 4-5-6 clutch is commanded OFF during a shift or when 4th gear ratio is detected in 1st gear. This condition must occur 3 times.
OBDII Code P0797 2018 GMC Sierra - Pressure Control Solenoid Valve 3 Stuck On - AutoCodes.com
P0797 2018 GMC Sierra Code - Pressure Control Solenoid Valve 3 Stuck On

What are the Possible Causes of the DTC P0797 2018 GMC Sierra?

  • 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 P0797 2018 GMC Sierra?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0797 2018 GMC Sierra 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 P0797 2018 GMC Sierra code?

Need more information on how to fix the P0797 2018 GMC Sierra code? Get Access to Factory Service Manuals

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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 P0797 2018 GMC Sierra Code

1. What does the OBDII code P0797 mean on a 2018 GMC Sierra?

P0797 indicates that the Powertrain Control Module (PCM) has detected that Pressure Control Solenoid Valve 3 is stuck in the "on" or closed position, disrupting proper transmission operation.

2. What are the common symptoms of code P0797 in a 2018 GMC Sierra?

Symptoms may include harsh or delayed shifting, transmission slipping, poor fuel efficiency, a check engine light, or the vehicle going into limp mode.

3. What causes the P0797 code to trigger in a 2018 GMC Sierra?

Common causes include a faulty pressure control solenoid, dirty or low transmission fluid, clogged transmission passages, wiring issues, or a malfunctioning PCM.

4. Can driving with code P0797 damage my 2018 GMC Sierra?

Yes, continuing to drive with this code can lead to further transmission damage, reduced performance, and higher repair costs.

5. How do I diagnose the P0797 code on a 2018 GMC Sierra?

Start by checking the transmission fluid level and condition, then inspect the wiring and connectors to the solenoid. Use a scan tool to monitor transmission pressure and solenoid operation.

6. How can I fix code P0797 in my 2018 GMC Sierra?

Repairs may involve replacing the faulty solenoid, flushing and refilling the transmission fluid, cleaning clogged passages, or repairing damaged wiring.

7. How much does it cost to repair the P0797 code on a 2018 GMC Sierra?

Repair costs can vary, but replacing a pressure control solenoid can range from $200 to $500, depending on labor and parts.

8. Can low transmission fluid cause the P0797 code?

Yes, low or dirty transmission fluid can prevent the solenoid from functioning properly and may trigger this code.

9. Do I need to replace the entire transmission if I get the P0797 code?

Not necessarily. In most cases, the issue can be resolved by repairing or replacing the affected solenoid or addressing fluid and wiring issues.

10. How can I prevent the P0797 code in my 2018 GMC Sierra?

Regular maintenance, including timely transmission fluid changes and inspections of wiring and connectors, can help prevent this issue.

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