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

• P0325 — P0325 — Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor). A fault in the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Typical causes: engine carbon buildup causing real detonation, damaged knock sensor wiring or connector, loose sensor mounting or incorrect torque.
• P0326 — P0326 — Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor). A fault in the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Typical causes: low-octane or contaminated fuel, damaged knock sensor wiring or connector, loose sensor mounting or incorrect torque.
• P0327 — Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor) (P0327): a powertrain (engine/transmission) fault affecting the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Most often caused by engine carbon buildup causing real detonation, loose sensor mounting or incorrect torque, failed knock sensor.
• P0328 — Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor) (P0328): a powertrain (engine/transmission) fault affecting the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Most often caused by engine carbon buildup causing real detonation, low-octane or contaminated fuel, failed knock sensor.
• P0329 — OBD2 code P0329 flags a problem with the knock (detonation) detection (knock sensor 1 circuit intermittent (bank 1 or single sensor)). Short, gentle driving to a shop is usually possible. Common culprits: loose sensor mounting or incorrect torque, damaged knock sensor wiring or connector, failed knock sensor.
• P032A — P032A — Knock Sensor 3 Circuit Bank 1. A fault in the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Typical causes: failed knock sensor, loose sensor mounting or incorrect torque, low-octane or contaminated fuel.
• P032B — Knock Sensor 3 Circuit Range/Performance Bank 1 (P032B): a powertrain (engine/transmission) fault affecting the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Most often caused by loose sensor mounting or incorrect torque, failed knock sensor, engine carbon buildup causing real detonation.
• P032C — OBD2 code P032C flags a problem with the knock (detonation) detection (knock sensor 3 circuit low bank 1). Short, gentle driving to a shop is usually possible. Common culprits: damaged knock sensor wiring or connector, loose sensor mounting or incorrect torque, engine carbon buildup causing real detonation.
• P032D — Knock Sensor 3 Circuit High Bank 1 (P032D): a powertrain (engine/transmission) fault affecting the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Most often caused by low-octane or contaminated fuel, loose sensor mounting or incorrect torque, damaged knock sensor wiring or connector.
• P032E — OBD2 code P032E flags a problem with the knock (detonation) detection (knock sensor 3 circuit intermittent bank 1). Short, gentle driving to a shop is usually possible. Common culprits: failed knock sensor, damaged knock sensor wiring or connector, low-octane or contaminated fuel.
• P0330 — P0330 — Knock Sensor 2 Circuit Malfunction (Bank 2). A fault in the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Typical causes: damaged knock sensor wiring or connector, failed knock sensor, engine carbon buildup causing real detonation.
• P0331 — Knock Sensor 2 Circuit Range/Performance (Bank 2) (P0331): a powertrain (engine/transmission) fault affecting the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Most often caused by failed knock sensor, damaged knock sensor wiring or connector, loose sensor mounting or incorrect torque.
• P0332 — OBD2 code P0332 flags a problem with the knock (detonation) detection (knock sensor 2 circuit low input (bank 2)). Short, gentle driving to a shop is usually possible. Common culprits: damaged knock sensor wiring or connector, low-octane or contaminated fuel, loose sensor mounting or incorrect torque.
• P0333 — OBD2 code P0333 flags a problem with the knock (detonation) detection (knock sensor 2 circuit high input (bank 2)). Short, gentle driving to a shop is usually possible. Common culprits: low-octane or contaminated fuel, loose sensor mounting or incorrect torque, engine carbon buildup causing real detonation.
• P0334 — Knock Sensor 2 Circuit Intermittent (Bank 2) (P0334): a powertrain (engine/transmission) fault affecting the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Most often caused by loose sensor mounting or incorrect torque, engine carbon buildup causing real detonation, low-octane or contaminated fuel.
• P0335 — P0335 — Crankshaft Position Sensor A Circuit Malfunction. A fault in the crankshaft position sensing. Driving is not recommended until fixed. Typical causes: damaged reluctor wheel on the crankshaft, incorrect sensor air gap, failed crankshaft position sensor.
• P0336 — P0336 — Crankshaft Position Sensor A Circuit Range/Performance. A fault in the crankshaft position sensing. Driving is not recommended until fixed. Typical causes: incorrect sensor air gap, damaged sensor wiring or connector, ECM signal processing fault.
• P0337 — Crankshaft Position Sensor A Circuit Low Input (P0337): a powertrain (engine/transmission) fault affecting the crankshaft position sensing. Driving is not recommended until fixed. Most often caused by ECM signal processing fault, damaged reluctor wheel on the crankshaft, damaged sensor wiring or connector.
• P0338 — Crankshaft Position Sensor A Circuit High Input (P0338): a powertrain (engine/transmission) fault affecting the crankshaft position sensing. Driving is not recommended until fixed. Most often caused by failed crankshaft position sensor, damaged reluctor wheel on the crankshaft, incorrect sensor air gap.
• P0339 — P0339 — Crankshaft Position Sensor A Circuit Intermittent. A fault in the crankshaft position sensing. Driving is not recommended until fixed. Typical causes: damaged sensor wiring or connector, ECM signal processing fault, incorrect sensor air gap.
• P033A — Knock Sensor 4 Circuit (Bank 2) (P033A): a powertrain (engine/transmission) fault affecting the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Most often caused by engine carbon buildup causing real detonation, low-octane or contaminated fuel, loose sensor mounting or incorrect torque.
• P033B — Knock Sensor 4 Circuit Range/Performance (Bank 2) (P033B): a powertrain (engine/transmission) fault affecting the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Most often caused by damaged knock sensor wiring or connector, failed knock sensor, low-octane or contaminated fuel.
• P033C — Knock Sensor 4 Circuit Low (Bank 2) (P033C): a powertrain (engine/transmission) fault affecting the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Most often caused by loose sensor mounting or incorrect torque, damaged knock sensor wiring or connector, engine carbon buildup causing real detonation.
• P033D — Knock Sensor 4 Circuit High (Bank 2) (P033D): a powertrain (engine/transmission) fault affecting the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Most often caused by low-octane or contaminated fuel, loose sensor mounting or incorrect torque, engine carbon buildup causing real detonation.