P0797: Pressure Control Solenoid C Stuck On
The P0797 code indicates that the transmission control module (TCM) has detected that the pressure control solenoid C is stuck in the 'on' position, causing excessive hydraulic pressure in the transmission. This solenoid regulates fluid pressure to the clutch packs and bands; when stuck on, it can lead to harsh shifts, slipping, or transmission damage. Common causes include electrical issues, contaminated transmission fluid, or a faulty solenoid.
01. Most Common Causes
- Faulty pressure control solenoid C
- Wiring or connector issues in the solenoid circuit
- Contaminated or low transmission fluid
- Internal transmission mechanical failure
02. Symptoms You Will Notice
- Harsh or delayed shifts
- Transmission slipping or overheating
- Check Engine Light illuminated
- Reduced fuel economy
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Inspect transmission fluid level and condition; change if dirty.
Step 3: Test solenoid C resistance and power/ground circuits with a multimeter.
Step 4: Perform a transmission pressure test to verify solenoid operation.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, driving with P0797 can cause severe transmission damage. Have it diagnosed and repaired immediately.
How much does it cost to fix?▼
Repair costs range from $150 to $400 for solenoid replacement, but can exceed $1,000 if internal transmission damage is found.