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

• P0099 — OBD2 code P0099 flags a problem with the throttle and intake air metering (intake air temperature sensor 2 circuit intermittent/erratic bank 1). Short, gentle driving to a shop is usually possible. Common culprits: failed electronic throttle motor, intake air leaks after the MAF sensor, dirty throttle body or stuck throttle plate.
• P009A — OBD2 code P009A flags a problem with the throttle and intake air metering (intake air temperature/ambient air temperature correlation). Short, gentle driving to a shop is usually possible. Common culprits: wiring or connector faults in the throttle circuit, contaminated or failed MAF/MAP sensor, dirty throttle body or stuck throttle plate.
• P009B — OBD2 code P009B flags a problem with the fuel delivery and mixture control (fuel pressure relief control circuit/open). Short, gentle driving to a shop is usually possible. Common culprits: contaminated or incorrect fuel, weak fuel pump or clogged fuel filter, faulty fuel pressure regulator.
• P009C — P009C — Fuel Pressure Relief Control Circuit Low. A fault in the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Typical causes: vacuum or intake leaks skewing the mixture, contaminated or incorrect fuel, faulty fuel pressure regulator.
• P009D — Fuel Pressure Relief Control Circuit High (P009D): 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 rail pressure sensor or wiring, faulty fuel pressure regulator, contaminated or incorrect fuel.
• P009E — P009E — Fuel Pressure Relief Control Performance/Stuck Off. 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, clogged or leaking fuel injectors, faulty fuel rail pressure sensor or wiring.
• P009F — Fuel Pressure Relief Control Stuck On (P009F): 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 vacuum or intake leaks skewing the mixture, contaminated or incorrect fuel, clogged or leaking fuel injectors.
• P00A0 — P00A0 — Charge Air Cooler Temperature Sensor Circuit Bank 2. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: corroded, loose or damaged connector, blown fuse feeding the circuit, poor ground connection.
• P00A1 — Charge Air Cooler Temperature Sensor Circuit Range/Performance Bank 2 (P00A1): 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 blown fuse feeding the circuit, control module driver fault, corroded, loose or damaged connector.
• P00A2 — P00A2 — Charge Air Cooler Temperature Sensor Circuit Low Bank 2. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: blown fuse feeding the circuit, faulty sensor or actuator of the affected circuit, control module driver fault.
• P00A3 — P00A3 — Charge Air Cooler Temperature Sensor Circuit High Bank 2. 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, control module driver fault.
• P00A4 — Charge Air Cooler Temperature Sensor Circuit Intermittent/Erratic Bank 2 (P00A4): 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 corroded, loose or damaged connector, open or shorted wiring in the circuit, blown fuse feeding the circuit.
• P00A5 — Intake Air Temperature Sensor 2 Circuit Bank 2 (P00A5): 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, dirty throttle body or stuck throttle plate, contaminated or failed MAF/MAP sensor.
• P00A6 — OBD2 code P00A6 flags a problem with the throttle and intake air metering (intake air temperature sensor 2 circuit range/performance bank 2). Short, gentle driving to a shop is usually possible. Common culprits: faulty throttle position sensor or pedal sensor, intake air leaks after the MAF sensor, failed electronic throttle motor.
• P00A7 — Intake Air Temperature Sensor 2 Circuit Low Bank 2 (P00A7): 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, contaminated or failed MAF/MAP sensor, dirty throttle body or stuck throttle plate.
• P00A8 — Intake Air Temperature Sensor 2 Circuit High Bank 2 (P00A8): 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, failed electronic throttle motor.
• P00A9 — Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic Bank 2 (P00A9): 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 dirty throttle body or stuck throttle plate, contaminated or failed MAF/MAP sensor, failed electronic throttle motor.
• P00AA — P00AA — Intake Air Temperature Sensor 1 Circuit Bank 2. 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, dirty throttle body or stuck throttle plate, faulty throttle position sensor or pedal sensor.
• P00AB — P00AB — Intake Air Temperature Sensor 1 Circuit Range/Performance Bank 2. A fault in the throttle and intake air metering. Short, gentle driving to a shop is usually possible. Typical causes: faulty throttle position sensor or pedal sensor, dirty throttle body or stuck throttle plate, failed electronic throttle motor.
• P00AC — Intake Air Temperature Sensor 1 Circuit Low Bank 2 (P00AC): 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 failed electronic throttle motor, faulty throttle position sensor or pedal sensor, intake air leaks after the MAF sensor.
• P00AD — Intake Air Temperature Sensor 1 Circuit High Bank 2 (P00AD): 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, faulty throttle position sensor or pedal sensor, intake air leaks after the MAF sensor.
• P00AE — Intake Air Temperature Sensor 1 Circuit Intermittent/Erratic Bank 2 (P00AE): 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.
• P00AF — OBD2 code P00AF flags a problem with the turbocharger / supercharger boost control (turbocharger/supercharger boost control "A" module performance). Short, gentle driving to a shop is usually possible. Common culprits: faulty boost pressure sensor, vacuum or actuator line damage, stuck wastegate or faulty boost control solenoid.
• P00B0 — Turbocharger/Supercharger Boost Control "B" Module Performance (P00B0): a powertrain (engine/transmission) fault affecting the turbocharger / supercharger boost control. Short, gentle driving to a shop is usually possible. Most often caused by vacuum or actuator line damage, clogged intake or exhaust (DPF/cat), faulty boost pressure sensor.