Shift Solenoid "C" Control Circuit High
The P0980 code indicates that the Powertrain Control Module (PCM) or Transmission Control Module (TCM) has detected a high voltage condition in the control circuit for shift solenoid 'C'. This typically means the circuit is shorted to voltage or has an open circuit that the module interprets as a high state, preventing proper gear shifts.
This code is considered high severity because it directly affects the transmission's ability to shift gears. Driving with this code can lead to internal transmission damage or leave the vehicle stuck in a single gear (limp mode).
Common symptoms
- Illuminated Check Engine Light
- Transmission stuck in a specific gear (limp mode)
- Harsh, delayed, or erratic gear shifts
- Decreased fuel efficiency
- Inability to shift into certain gears
Likely causes
- Defective shift solenoid 'C'
- Short to voltage in the shift solenoid 'C' wiring harness
- Open circuit or poor electrical connection in the solenoid circuit
- Contaminated or dirty transmission fluid causing solenoid malfunction
- 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 metal debris, which can cause solenoid failure or indicate internal damage.
Inspect the wiring harness and connectors for shift solenoid 'C'.
Look for: Frayed wires, melted insulation, or corroded pins that could cause a short to voltage or an open circuit.
Measure the resistance of shift solenoid 'C' using a digital multimeter.
Look for: Resistance readings outside the manufacturer's specified range, indicating an internally failed solenoid.
Check for voltage at the solenoid connector with the key on, engine off.
Look for: Continuous battery voltage when the PCM/TCM is not commanding the solenoid on, indicating a short to power in the harness.
Perform a bidirectional scan tool test to command the solenoid on and off.
Look for: A lack of audible clicking from the transmission pan or no change in electrical state on the scan tool data, confirming the circuit or solenoid is unresponsive.
This page explains the generic P0980 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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