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

• P2316 — OBD2 code P2316 flags a problem with the ignition system (ignition coil "F" primary control circuit high). Short, gentle driving to a shop is usually possible. Common culprits: worn spark plugs or wrong plug gap, moisture or oil in the spark plug wells, failed ignition coil or coil pack.
• P2317 — P2317 — Ignition Coil "F" Secondary Circuit. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: damaged coil wiring or connector, faulty ignition control circuit in the ECM, failed ignition coil or coil pack.
• P2318 — OBD2 code P2318 flags a problem with the ignition system (ignition coil "G" primary control circuit low). Short, gentle driving to a shop is usually possible. Common culprits: worn spark plugs or wrong plug gap, damaged coil wiring or connector, failed ignition coil or coil pack.
• P2319 — Ignition Coil "G" Primary Control Circuit High (P2319): a powertrain (engine/transmission) fault affecting the ignition system. Short, gentle driving to a shop is usually possible. Most often caused by moisture or oil in the spark plug wells, faulty ignition control circuit in the ECM, worn spark plugs or wrong plug gap.
• P2320 — P2320 — Ignition Coil "G" Secondary Circuit. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: moisture or oil in the spark plug wells, failed ignition coil or coil pack, damaged coil wiring or connector.
• P2321 — OBD2 code P2321 flags a problem with the ignition system (ignition coil "H" primary control circuit low). Short, gentle driving to a shop is usually possible. Common culprits: moisture or oil in the spark plug wells, damaged coil wiring or connector, worn spark plugs or wrong plug gap.
• P2322 — P2322 — Ignition Coil "H" Primary Control Circuit High. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: worn spark plugs or wrong plug gap, moisture or oil in the spark plug wells, failed ignition coil or coil pack.
• P2323 — P2323 — Ignition Coil "H" Secondary Circuit. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: worn spark plugs or wrong plug gap, failed ignition coil or coil pack, faulty ignition control circuit in the ECM.
• P2324 — P2324 — Ignition Coil "I" Primary Control Circuit Low. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: damaged coil wiring or connector, failed ignition coil or coil pack, faulty ignition control circuit in the ECM.
• P2326 — OBD2 code P2326 flags a problem with the ignition system (ignition coil "I" secondary circuit). Short, gentle driving to a shop is usually possible. Common culprits: faulty ignition control circuit in the ECM, moisture or oil in the spark plug wells, damaged coil wiring or connector.
• P2327 — Ignition Coil "J" Primary Control Circuit Low (P2327): a powertrain (engine/transmission) fault affecting the ignition system. Short, gentle driving to a shop is usually possible. Most often caused by worn spark plugs or wrong plug gap, moisture or oil in the spark plug wells, faulty ignition control circuit in the ECM.
• P2328 — P2328 — Ignition Coil "J" Primary Control Circuit High. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: damaged coil wiring or connector, moisture or oil in the spark plug wells, worn spark plugs or wrong plug gap.
• P2329 — P2329 — Ignition Coil "J" Secondary Circuit. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: moisture or oil in the spark plug wells, failed ignition coil or coil pack, faulty ignition control circuit in the ECM.
• P2330 — OBD2 code P2330 flags a problem with the ignition system (ignition coil "K" primary control circuit low). Short, gentle driving to a shop is usually possible. Common culprits: moisture or oil in the spark plug wells, damaged coil wiring or connector, failed ignition coil or coil pack.
• P2331 — Ignition Coil "K" Primary Control Circuit High (P2331): a powertrain (engine/transmission) fault affecting the ignition system. Short, gentle driving to a shop is usually possible. Most often caused by moisture or oil in the spark plug wells, worn spark plugs or wrong plug gap, damaged coil wiring or connector.
• P2333 — P2333 — Ignition Coil "L" Primary Control Circuit Low. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: faulty ignition control circuit in the ECM, damaged coil wiring or connector, failed ignition coil or coil pack.
• P2335 — Ignition Coil "L" Secondary Circuit (P2335): a powertrain (engine/transmission) fault affecting the ignition system. Short, gentle driving to a shop is usually possible. Most often caused by failed ignition coil or coil pack, worn spark plugs or wrong plug gap, damaged coil wiring or connector.
• P2336 — Cylinder 1 Above Knock Threshold (P2336): 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, failed knock sensor, engine carbon buildup causing real detonation.
• P2337 — Cylinder 2 Above Knock Threshold (P2337): 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, failed knock sensor, damaged knock sensor wiring or connector.
• P2338 — P2338 — Cylinder 3 Above Knock Threshold. 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, engine carbon buildup causing real detonation.
• P2339 — OBD2 code P2339 flags a problem with the knock (detonation) detection (cylinder 4 above knock threshold). Short, gentle driving to a shop is usually possible. Common culprits: loose sensor mounting or incorrect torque, damaged knock sensor wiring or connector, engine carbon buildup causing real detonation.
• P2341 — Cylinder 6 Above Knock Threshold (P2341): 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.
• P2342 — OBD2 code P2342 flags a problem with the knock (detonation) detection (cylinder 7 above knock threshold). Short, gentle driving to a shop is usually possible. Common culprits: failed knock sensor, low-octane or contaminated fuel, engine carbon buildup causing real detonation.
• P2343 — Cylinder 8 Above Knock Threshold (P2343): 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, engine carbon buildup causing real detonation, damaged knock sensor wiring or connector.