P0797
UniversalPressure Control Solenoid C Stuck On
Medium SeverityThe P0797 code indicates that the transmission's Pressure Control Solenoid C is stuck in the 'on' position, meaning it is constantly applying pressure. This malfunction prevents the transmission from regulating fluid pressure correctly, which can lead to shifting problems or poor transmission performance.
⚠️ Before You Begin (Safety First)
Always ensure the vehicle is safely supported on jack stands when working underneath. Transmission fluid can be hot; allow the vehicle to cool before servicing. Disconnect the battery before performing electrical work.
Common Symptoms
- Harsh or erratic shifts
- Delayed transmission engagement
- Transmission slipping between gears
- Poor fuel economy
- Check Engine Light illuminated
Common Causes
- Faulty Pressure Control Solenoid C
- Contaminated transmission fluid or clogged filter
- Wiring harness issues or poor electrical connection to the solenoid
- Internal transmission mechanical failure
- Failed Transmission Control Module (TCM) or Powertrain Control Module (PCM)
Frequently reported on: Ford F-150 2008-2014, Chevrolet Silverado 2007-2013, Honda Accord 2003-2007, Toyota Camry 2002-2006, Dodge Grand Caravan 2008-2010
Diagnostic Steps
- Check transmission fluid level and condition. Ensure it is at the correct level and not dark or burnt.
- Inspect the wiring harness and connectors leading to the transmission for damage, corrosion, or loose connections.
- Clear the code and test drive the vehicle to see if the code returns.
- If comfortable, drop the transmission pan, inspect for debris, replace the transmission filter, and replace the faulty Pressure Control Solenoid C.
- Refill with fresh, correct type of transmission fluid.
👨🔧 When to Call a Professional
If you are experiencing severe or erratic shifting issues, or if the code reappears after attempting basic diagnostics and fluid changes, it's best to consult a professional transmission specialist. Transmission repairs can be complex and require specialized tools.
Commonly Asked Questions
What does P0797 specifically indicate?
P0797 means the transmission's Pressure Control Solenoid C is stuck in an 'on' state, causing incorrect hydraulic pressure regulation within the transmission.
Can I continue driving with a P0797 code?
While it might be possible to drive short distances, it's not recommended. Continued driving with incorrect transmission pressure can lead to further, more expensive transmission damage.
How can I test the Pressure Control Solenoid C?
You can test the solenoid by checking its electrical resistance with a multimeter and by applying battery voltage to see if it actuates. This often requires removing the transmission pan.
Is replacing the Pressure Control Solenoid C a difficult DIY repair?
It is generally considered an advanced DIY repair, as it involves working with transmission fluid, dropping the transmission pan, and understanding the internal components of the transmission.
Could contaminated fluid be the only cause of P0797?
Yes, severely contaminated or low transmission fluid can cause a solenoid to stick or malfunction. Always check fluid condition and level first.