Pressure Control Solenoid "C" Control Circuit/Open
Diagnostic trouble code P0968 indicates that the powertrain control module (PCM) or transmission control module (TCM) has detected an open circuit or electrical malfunction in the control circuit for pressure control solenoid 'C'. This solenoid is responsible for regulating hydraulic pressure within the transmission to facilitate smooth and precise gear shifts.
This code is considered high severity because improper hydraulic pressure can lead to harsh shifting, transmission slipping, and potential internal transmission damage if driven extensively.
Common symptoms
- Illuminated Check Engine Light
- Harsh or erratic transmission shifting
- Transmission slipping between gears
- Vehicle stuck in 'limp mode' (restricted to a single gear)
- Decreased fuel economy
Likely causes
- Damaged, corroded, or loose wiring and connectors in the solenoid 'C' circuit
- Defective transmission pressure control solenoid 'C'
- Low or contaminated transmission fluid
- Clogged internal transmission fluid passages
- Faulty transmission control module (TCM) or powertrain control module (PCM)
What to check before replacing parts
Check the transmission fluid level and condition.
Look for: Fluid that is low, burnt, or heavily contaminated with debris indicates a potential mechanical issue or lack of maintenance that could affect solenoid operation.
Visually inspect the wiring harness and connectors for the transmission pressure control solenoid 'C'.
Look for: Look for frayed wires, melted insulation, corrosion on pins, or loose connections that would cause an open circuit.
Test the resistance of pressure control solenoid 'C' using a digital multimeter.
Look for: Compare the measured resistance to the manufacturer's specifications; an infinite reading (OL) indicates an internal open in the solenoid.
Check for voltage and ground at the solenoid connector while commanding the solenoid on with a scan tool.
Look for: The presence of proper voltage and ground confirms the circuit from the module is intact; lack of either indicates a wiring issue between the module and the solenoid.
Perform a continuity test on the wiring between the TCM/PCM and the solenoid connector.
Look for: High resistance or no continuity indicates a broken wire in the harness that needs to be repaired or replaced.
This page explains the generic P0968 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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