Pressure Control Solenoid C Performance or Stuck Off
The transmission control module (TCM) sets this code when it detects that pressure control solenoid 'C' is not operating correctly or is stuck in the off position. This prevents the transmission from properly regulating the hydraulic pressure needed for smooth gear engagement and shifting.
This code requires immediate attention as driving with incorrect hydraulic pressure can cause severe internal transmission damage and potentially leave the vehicle stranded.
Common symptoms
- Illuminated Check Engine Light
- Transmission slipping between gears
- Harsh or erratic shifting
- Vehicle stuck in limp mode
- Delayed gear engagement
Likely causes
- Low or dirty transmission fluid
- Faulty pressure control solenoid C
- Clogged transmission fluid filter or hydraulic passages
- Damaged wiring or loose connectors in the transmission harness
- Defective transmission valve body
- Failing Transmission Control Module (TCM)
What to check before replacing parts
Check the transmission fluid level and condition.
Look for: Look for fluid that is low, burnt, or heavily contaminated with metal shavings, which indicates internal wear or a leak.
Inspect the wiring harness and connectors to the transmission.
Look for: Check for frayed wires, corrosion, or loose connections that could interrupt the signal to solenoid C.
Test pressure control solenoid C with a digital multimeter.
Look for: Measure the internal resistance of the solenoid and compare it to factory specifications; an out-of-range reading indicates a failed solenoid.
Command the solenoid using a bi-directional scan tool.
Look for: Listen for an audible click or monitor the pressure changes on the scanner to verify if the solenoid is mechanically responding.
Perform a manual hydraulic pressure test on the transmission.
Look for: Compare the actual line pressure against the manufacturer's specifications to determine if the issue is in the valve body or internal pump.
This page explains the generic P0796 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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