OBD2 Fault Code Library

Free lookup for thousands of OBD2 trouble codes: filter by family, read short meanings, and open deeper articles. Desktop ELM327 scanner with live data and AI guidance.

OBD2 symptoms

Look up diagnostic trouble codes by what the car is doing: misfire, overheating, rough idle, a check engine light, and other common symptoms.

• Engine misfire
• Engine overheating
• Rough idle
• Check engine light
• Poor fuel economy
• Hard starting
• Engine stalling
• Catalytic converter efficiency
• Oxygen sensor fault
• EVAP leak
• Thermostat not reaching temperature
• Lean air-fuel mixture
• Rich air-fuel mixture
• EGR flow fault
• Engine knock
• Charging system
• Throttle position
• Mass airflow sensor
• Turbo underboost
• Coolant temperature sensor
• Transmission fault

• P0C1C — Auxiliary Transmission Fluid Pump Control Module Internal Temperature Sensor Circuit (P0C1C): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by failed shift or pressure control solenoid, wiring or connector faults in the valve body harness, valve body wear.
• P0C1D — P0C1D — Auxiliary Transmission Fluid Pump Control Module Internal Temperature Sensor Circuit Range/Performance. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: valve body wear, faulty transmission speed sensor, internal mechanical wear (clutches, torque converter).
• P0C1E — Auxiliary Transmission Fluid Pump Control Module Internal Temperature Sensor Circuit Low P0C1F Auxiliary Transmission Fluid Pump Control Module Internal Temperature Sensor Circuit High (P0C1E): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by faulty transmission speed sensor, failed shift or pressure control solenoid, internal mechanical wear (clutches, torque converter).
• P0C20 — OBD2 code P0C20 flags a problem with the automatic transmission control (auxiliary transmission fluid pump phase U-V-W circuit/open). Short, gentle driving to a shop is usually possible. Common culprits: wiring or connector faults in the valve body harness, low or degraded transmission fluid, faulty transmission speed sensor.
• P0C21 — P0C21 — Auxiliary Transmission Fluid Pump Phase U-V-W Circuit Low. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: internal mechanical wear (clutches, torque converter), faulty transmission speed sensor, valve body wear.
• P0C22 — OBD2 code P0C22 flags a problem with the automatic transmission control (auxiliary transmission fluid pump phase U-V-W circuit high). Short, gentle driving to a shop is usually possible. Common culprits: valve body wear, low or degraded transmission fluid, failed shift or pressure control solenoid.
• P0C23 — Auxiliary Transmission Fluid Pump Control Module Circuit/Open (P0C23): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by wiring or connector faults in the valve body harness, valve body wear, failed shift or pressure control solenoid.
• P0C24 — Auxiliary Transmission Fluid Pump Control Module Circuit Low (P0C24): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by valve body wear, wiring or connector faults in the valve body harness, failed shift or pressure control solenoid.
• P0C25 — Auxiliary Transmission Fluid Pump Control Module Circuit High (P0C25): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by valve body wear, wiring or connector faults in the valve body harness, internal mechanical wear (clutches, torque converter).
• P0C26 — P0C26 — Auxiliary Transmission Fluid Pump Motor Current. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: internal mechanical wear (clutches, torque converter), valve body wear, wiring or connector faults in the valve body harness.
• P0C27 — OBD2 code P0C27 flags a problem with the automatic transmission control (auxiliary transmission fluid pump motor current low). Short, gentle driving to a shop is usually possible. Common culprits: valve body wear, internal mechanical wear (clutches, torque converter), faulty transmission speed sensor.
• P0C28 — Auxiliary Transmission Fluid Pump Motor Current High (P0C28): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by low or degraded transmission fluid, valve body wear, internal mechanical wear (clutches, torque converter).
• P0C29 — OBD2 code P0C29 flags a problem with the automatic transmission control (auxiliary transmission fluid pump driver circuit performance). Short, gentle driving to a shop is usually possible. Common culprits: failed shift or pressure control solenoid, wiring or connector faults in the valve body harness, internal mechanical wear (clutches, torque converter).
• P0C2A — Auxiliary Transmission Fluid Pump Motor Stalled (P0C2A): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by failed shift or pressure control solenoid, internal mechanical wear (clutches, torque converter), low or degraded transmission fluid.
• P0C2B — Auxiliary Transmission Fluid Pump Control Module Feedback Signal (P0C2B): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by internal mechanical wear (clutches, torque converter), failed shift or pressure control solenoid, low or degraded transmission fluid.
• P0C2C — P0C2C — Auxiliary Transmission Fluid Pump Control Module Feedback Signal Range/Performance. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: low or degraded transmission fluid, wiring or connector faults in the valve body harness, failed shift or pressure control solenoid.
• P0C2D — P0C2D — Auxiliary Transmission Fluid Pump Control Module Feedback Signal Low. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: internal mechanical wear (clutches, torque converter), faulty transmission speed sensor, valve body wear.
• P0C2E — P0C2E — Auxiliary Transmission Fluid Pump Control Module Feedback Signal High. A fault in the automatic transmission control. Short, gentle driving to a shop is usually possible. Typical causes: low or degraded transmission fluid, faulty transmission speed sensor, failed shift or pressure control solenoid.
• P0C2F — OBD2 code P0C2F flags a problem with the sensor and actuator circuits (internal control module drive motor/generator - engine speed sensor performance). The car is usually drivable while you plan the repair. Common culprits: faulty sensor or actuator of the affected circuit, control module driver fault, corroded, loose or damaged connector.
• P0C30 — P0C30 — Hybrid Battery Pack State of Charge High. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: poor ground connection, faulty sensor or actuator of the affected circuit, corroded, loose or damaged connector.
• P0C31 — P0C31 — Inverter "B" Cooling System Performance. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: open or shorted wiring in the circuit, poor ground connection, blown fuse feeding the circuit.
• P0C32 — Hybrid Battery Cooling System Performance (P0C32): a powertrain (engine/transmission) fault affecting the sensor and actuator circuits. The car is usually drivable while you plan the repair. Most often caused by poor ground connection, faulty sensor or actuator of the affected circuit, corroded, loose or damaged connector.
• P0C33 — OBD2 code P0C33 flags a problem with the sensor and actuator circuits (hybrid battery temperature sensor "F" circuit). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, open or shorted wiring in the circuit, corroded, loose or damaged connector.
• P0C34 — Hybrid Battery Temperature Sensor "F" Circuit Range/Performance (P0C34): a powertrain (engine/transmission) fault affecting the sensor and actuator circuits. The car is usually drivable while you plan the repair. Most often caused by faulty sensor or actuator of the affected circuit, poor ground connection, open or shorted wiring in the circuit.