P0797 Automatic transmission pressure control solenoid valve “C” is stuck on

P0797 – OBD-II Trouble Code Technical Description

Trouble code P0797 indicates that the PCM has detected that the pressure control solenoid valve "C" is stuck in the on position.

What does the fault code mean P0797?

Trouble code P0797 indicates that the automatic transmission control module (PCM) has detected that the pressure control solenoid valve “C” is stuck in the ON position. This means that the valve that regulates transmission fluid pressure is stuck in one of the states normally used to control transmissions. The PCM regulates the transmission fluid pressure required for proper transmission operation by taking into account various parameters such as vehicle speed, engine speed, engine load and throttle position. If the actual pressure value does not match the set pressure, error P0797 occurs.

Possible reasons

Several possible reasons for the P0797 trouble code:

• Stuck pressure control solenoid valve “C”: The valve may become stuck on due to wear, contamination or other damage.
• Electrical circuit problems: An open, short or other problem in the electrical circuit associated with solenoid valve “C” may cause it to not operate properly.
• Valve malfunction due to low transmission fluid level: Low transmission fluid levels can cause the pressure control valve to malfunction, including sticking.
• Problems with the automatic transmission hydraulic system: Leaks, clogs, or other problems in the transmission hydraulic system can cause incorrect pressure and thus a stuck pressure control valve.
• PCM malfunctions: Problems with the engine control module (PCM), which controls the pressure control valve and processes signals from sensors, can also cause P0797.

These are just some of the possible reasons. To accurately determine the cause, it is necessary to conduct a more in-depth diagnosis of the automatic transmission system using appropriate equipment and tools.

What are the symptoms of a fault code? P0797?

Symptoms for DTC P0797 may include the following:

• Gear shifting problems: The vehicle may shift between gears in an unusual manner, such as hesitating, jerking, or sudden changes in speed.
• Unusual sounds or vibrations: If pressure control valve “C” is not operating properly, unusual noises or vibrations may occur in the transmission area or under the hood.
• Delays in gear shifting: There may be a delay or lack of response from the transmission to driver commands to change gears.
• Increased fuel consumption: Improper transmission operation due to improper transmission fluid pressure may result in increased fuel consumption.
• Check Engine Light Illuminates: The appearance of the P0797 code is usually accompanied by the Check Engine light on the dashboard.

These symptoms may occur to varying degrees depending on the specific problem in the transmission control system. If these symptoms occur, it is recommended that you contact a qualified auto mechanic for diagnosis and repair.

How to diagnose a fault code P0797?

The following approach is recommended to diagnose DTC P0797:

1. Reading fault codes: Use a diagnostic scanner to read trouble codes in the engine management system. Verify that code P0797 is present and make a note of other codes if they are also displayed.
2. Visual inspection: Inspect the engine compartment and transmission area for visible damage, leaks or related problems.
3. Checking the transmission fluid level: Check the transmission fluid level according to the manufacturer's recommendations. Low fluid levels can cause the transmission to malfunction.
4. Electrical circuit diagnostics: Check the electrical connections and wiring associated with the pressure control solenoid valve “C”. Make sure all connections are secure and intact and that there are no breaks or short circuits.
5. Pressure Control Solenoid Valve “C” Testing: Test the valve for malfunction or sticking. If the valve is not working properly, it should be replaced or repaired.
6. Diagnostics of the automatic transmission hydraulic system: Check the transmission hydraulic system for leaks, blockages, or other problems that may affect the operation of the pressure control solenoid valve.
7. Check PCM: If necessary, check the condition of the engine control module (PCM) and its software. Problems with the PCM can also be the cause of the P0797 code.

In case of doubt or lack of experience, it is recommended to contact a qualified auto mechanic or service center.

Diagnostic errors

When diagnosing DTC P0797, the following errors may occur:

• Insufficient checking of electrical connections: All electrical connections and wiring associated with the pressure control solenoid valve “C” must be carefully checked. Incorrect or incomplete connections may result in insufficient diagnosis.
• Replacement of components without prior testing: Sometimes mechanics may be tempted to replace components such as the pressure control solenoid valve without first doing a full diagnosis, which can be unnecessary and ineffective.
• Insufficient diagnostics of the hydraulic system: Problems in the transmission hydraulic system, such as leaks or blockages, may be missed during diagnosis, which may cause P0797 to reappear after components are replaced.
• Ignoring other fault codes: Sometimes other trouble codes can affect the transmission system and cause P0797 to appear, but they may be undiagnosed or ignored.
• Misinterpretation of symptoms: Some symptoms may be mistakenly interpreted as problems with the pressure control valve, when the root of the problem may lie in other components of the transmission system.

To avoid these errors, it is important to carry out a complete and systematic diagnosis, taking into account all possible causes and factors affecting the operation of the automatic transmission system.

How serious is the fault code? P0797?

Trouble code P0797 indicates a problem with the automatic transmission pressure control solenoid valve “C”. Although this code itself is not critical in the sense that it does not indicate an immediate danger to the safety or performance of the engine, it does indicate serious problems that may affect the normal operation of the transmission.

Improper operation of the pressure control solenoid valve can result in unstable or incorrect transmission between gears, which can ultimately lead to transmission wear and other serious damage. However, the P0797 code can also lead to increased fuel consumption and poor driving performance due to improper gear shifting.

Although the P0797 code is not an emergency problem, it is recommended to treat it as a serious warning of a problem in the automatic transmission system and requiring prompt attention. You should immediately contact a qualified auto mechanic to diagnose and repair the problem to prevent further damage and ensure proper transmission operation.

What repair will help eliminate the code? P0797?

Troubleshooting DTC P0797 typically involves the following steps:

1. Replacing or Repairing Pressure Control Solenoid Valve “C”: If the valve is faulty or stuck, it should be replaced or repaired.
2. Checking and replacing electrical connections and wiring: Check the condition of the electrical connections and wiring related to the solenoid valve “C”. Replace or repair any damaged or broken wires.
3. Diagnostics and repair of automatic transmission hydraulic system: Inspect the transmission hydraulic system for leaks, blockages, or other problems. Correct any problems found.
4. Checking and reprogramming the PCM: In rare cases, the problem may be related to the engine control module (PCM). Perform further diagnostics on the PCM and, if necessary, reprogram or replace it.
5. Real world testing: After repair work is carried out, it is recommended to test drive the vehicle to check the operation of the transmission and ensure that the problem has been successfully fixed.

These steps will help eliminate the causes of the P0797 trouble code and restore normal transmission operation. If you are unsure of your skills or experience, it is recommended that you contact a professional auto mechanic or service center for repair work.

How to Diagnose and Fix P0797 Engine Code - OBD II Trouble Code Explain

P0951 – Brand-specific information

Trouble code P0797 can have different interpretations depending on the vehicle manufacturer. Here is a breakdown of the P0797 code for some popular car brands:

1. Ford, Lincoln, Mercury: Pressure control solenoid valve “C” – stuck on.
2. Chevrolet, GMC, Cadillac, Buick: Pressure control solenoid valve “C” is stuck on.
3. Toyota, Lexus, Scion: Pressure control solenoid valve “C” – stuck on.
4. Honda Acura: Pressure control solenoid valve “C” – stuck on.
5. Volkswagen, Audi, BMW, Mercedes-Benz: Pressure control solenoid valve “C” is stuck on.
6. Subaru, Mazda, Hyundai, Kia: Pressure control solenoid valve “C” is stuck on.
7. Nissan, Infiniti: Pressure control solenoid valve “C” – stuck on.
8. Chrysler, Dodge, Jeep, Ram: Pressure control solenoid valve “C” is stuck on.

Please note that these are general guidelines only and your specific model and year of vehicle may require more detailed diagnostics and trouble code interpretation. If you are experiencing a problem with a P0797 code, it is recommended that you consult the official repair manuals for your specific vehicle or take it to a qualified auto mechanic for further diagnosis and repair.