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

• P02E4 — Diesel Intake Air Flow Control Stuck Open (P02E4): a powertrain (engine/transmission) fault affecting the throttle and intake air metering. Short, gentle driving to a shop is usually possible. Most often caused by faulty throttle position sensor or pedal sensor, contaminated or failed MAF/MAP sensor, wiring or connector faults in the throttle circuit.
• P02E5 — Diesel Intake Air Flow Control Stuck Closed (P02E5): a powertrain (engine/transmission) fault affecting the throttle and intake air metering. Short, gentle driving to a shop is usually possible. Most often caused by wiring or connector faults in the throttle circuit, faulty throttle position sensor or pedal sensor, intake air leaks after the MAF sensor.
• P02E6 — OBD2 code P02E6 flags a problem with the throttle and intake air metering (diesel intake air flow position sensor circuit). Short, gentle driving to a shop is usually possible. Common culprits: failed electronic throttle motor, dirty throttle body or stuck throttle plate, intake air leaks after the MAF sensor.
• P02E7 — OBD2 code P02E7 flags a problem with the throttle and intake air metering (diesel intake air flow position sensor circuit range/performance). Short, gentle driving to a shop is usually possible. Common culprits: failed electronic throttle motor, wiring or connector faults in the throttle circuit, dirty throttle body or stuck throttle plate.
• P02E8 — OBD2 code P02E8 flags a problem with the throttle and intake air metering (diesel intake air flow position sensor circuit low). Short, gentle driving to a shop is usually possible. Common culprits: wiring or connector faults in the throttle circuit, faulty throttle position sensor or pedal sensor, intake air leaks after the MAF sensor.
• P02E9 — P02E9 — Diesel Intake Air Flow Position Sensor Circuit High. A fault in the throttle and intake air metering. Short, gentle driving to a shop is usually possible. Typical causes: contaminated or failed MAF/MAP sensor, failed electronic throttle motor, intake air leaks after the MAF sensor.
• P02EA — Diesel Intake Air Flow Position Sensor Circuit Intermittent/Erratic (P02EA): a powertrain (engine/transmission) fault affecting the throttle and intake air metering. Short, gentle driving to a shop is usually possible. Most often caused by intake air leaks after the MAF sensor, failed electronic throttle motor, contaminated or failed MAF/MAP sensor.
• P02EB — P02EB — Diesel Intake Air Flow Control Motor Current Range/Performance. A fault in the throttle and intake air metering. Short, gentle driving to a shop is usually possible. Typical causes: dirty throttle body or stuck throttle plate, faulty throttle position sensor or pedal sensor, intake air leaks after the MAF sensor.
• P02EC — Diesel Intake Air Flow Control System - High Air Flow Detected (P02EC): a powertrain (engine/transmission) fault affecting the throttle and intake air metering. Short, gentle driving to a shop is usually possible. Most often caused by contaminated or failed MAF/MAP sensor, wiring or connector faults in the throttle circuit, faulty throttle position sensor or pedal sensor.
• P02ED — Diesel Intake Air Flow Control System - Low Air Flow Detected (P02ED): a powertrain (engine/transmission) fault affecting the throttle and intake air metering. Short, gentle driving to a shop is usually possible. Most often caused by intake air leaks after the MAF sensor, dirty throttle body or stuck throttle plate, wiring or connector faults in the throttle circuit.
• P02EE — P02EE — Cylinder 1 Injector Circuit Range/Performance. A fault in the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Typical causes: weak fuel pump or clogged fuel filter, faulty fuel rail pressure sensor or wiring, contaminated or incorrect fuel.
• P02EF — Cylinder 2 Injector Circuit Range/Performance (P02EF): a powertrain (engine/transmission) fault affecting the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Most often caused by clogged or leaking fuel injectors, contaminated or incorrect fuel, weak fuel pump or clogged fuel filter.
• P02F0 — OBD2 code P02F0 flags a problem with the fuel delivery and mixture control (cylinder 3 injector circuit range/performance). Short, gentle driving to a shop is usually possible. Common culprits: faulty fuel pressure regulator, vacuum or intake leaks skewing the mixture, faulty fuel rail pressure sensor or wiring.
• P02F1 — OBD2 code P02F1 flags a problem with the fuel delivery and mixture control (cylinder 4 injector circuit range/performance). Short, gentle driving to a shop is usually possible. Common culprits: vacuum or intake leaks skewing the mixture, faulty fuel rail pressure sensor or wiring, weak fuel pump or clogged fuel filter.
• P02F2 — OBD2 code P02F2 flags a problem with the fuel delivery and mixture control (cylinder 5 injector circuit range/performance). Short, gentle driving to a shop is usually possible. Common culprits: weak fuel pump or clogged fuel filter, faulty fuel rail pressure sensor or wiring, clogged or leaking fuel injectors.
• P02F3 — P02F3 — Cylinder 6 Injector Circuit Range/Performance. A fault in the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Typical causes: faulty fuel rail pressure sensor or wiring, weak fuel pump or clogged fuel filter, faulty fuel pressure regulator.
• P02F4 — Cylinder 7 Injector Circuit Range/Performance (P02F4): a powertrain (engine/transmission) fault affecting the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Most often caused by faulty fuel pressure regulator, vacuum or intake leaks skewing the mixture, faulty fuel rail pressure sensor or wiring.
• P02F5 — OBD2 code P02F5 flags a problem with the fuel delivery and mixture control (cylinder 8 injector circuit range/performance). Short, gentle driving to a shop is usually possible. Common culprits: faulty fuel pressure regulator, weak fuel pump or clogged fuel filter, vacuum or intake leaks skewing the mixture.
• P02F6 — Cylinder 9 Injector Circuit Range/Performance (P02F6): a powertrain (engine/transmission) fault affecting the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Most often caused by contaminated or incorrect fuel, faulty fuel rail pressure sensor or wiring, weak fuel pump or clogged fuel filter.
• P02F7 — OBD2 code P02F7 flags a problem with the fuel delivery and mixture control (cylinder 10 injector circuit range/performance). Short, gentle driving to a shop is usually possible. Common culprits: faulty fuel pressure regulator, vacuum or intake leaks skewing the mixture, contaminated or incorrect fuel.
• P02F8 — Cylinder 11 Injector Circuit Range/Performance (P02F8): a powertrain (engine/transmission) fault affecting the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Most often caused by contaminated or incorrect fuel, weak fuel pump or clogged fuel filter, faulty fuel rail pressure sensor or wiring.
• P02F9 — Cylinder 12 Injector Circuit Range/Performance (P02F9): a powertrain (engine/transmission) fault affecting the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Most often caused by clogged or leaking fuel injectors, vacuum or intake leaks skewing the mixture, faulty fuel pressure regulator.
• P02FA — OBD2 code P02FA flags a problem with the throttle and intake air metering (diesel intake air flow position sensor minimum/maximum stop performance). Short, gentle driving to a shop is usually possible. Common culprits: faulty throttle position sensor or pedal sensor, dirty throttle body or stuck throttle plate, intake air leaks after the MAF sensor.
• P0300 — P0300 — Random/Multiple Cylinder Misfire Detected. A fault in the engine misfire monitoring. Short, gentle driving to a shop is usually possible. Typical causes: low compression in the affected cylinder(s), incorrect fuel pressure or a weak fuel pump, failed ignition coil or coil wiring.