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.

P00B1 — Radiator Coolant Temperature Sensor Circuit (P00B1): a powertrain (engine/transmission) fault affecting the engine cooling and temperature control. Short, gentle driving to a shop is usually possible. Most often caused by water pump or radiator issues, failed cooling fan or fan relay, low coolant level or air in the system.
P00B2 — Radiator Coolant Temperature Sensor Circuit Range/Performance (P00B2): a powertrain (engine/transmission) fault affecting the engine cooling and temperature control. Short, gentle driving to a shop is usually possible. Most often caused by low coolant level or air in the system, thermostat stuck open or closed, faulty coolant temperature sensor.
P00B3 — OBD2 code P00B3 flags a problem with the engine cooling and temperature control (radiator coolant temperature sensor circuit low). Short, gentle driving to a shop is usually possible. Common culprits: water pump or radiator issues, faulty coolant temperature sensor, wiring faults in the sensor circuit.
P00B4 — Radiator Coolant Temperature Sensor Circuit High (P00B4): a powertrain (engine/transmission) fault affecting the engine cooling and temperature control. Short, gentle driving to a shop is usually possible. Most often caused by faulty coolant temperature sensor, water pump or radiator issues, low coolant level or air in the system.
P00B5 — Radiator Coolant Temperature Sensor Circuit Intermittent/Erratic (P00B5): a powertrain (engine/transmission) fault affecting the engine cooling and temperature control. Short, gentle driving to a shop is usually possible. Most often caused by wiring faults in the sensor circuit, faulty coolant temperature sensor, failed cooling fan or fan relay.
P00B6 — P00B6 — Radiator Coolant Temperature/Engine Coolant Temperature Correlation. A fault in the engine cooling and temperature control. Short, gentle driving to a shop is usually possible. Typical causes: water pump or radiator issues, failed cooling fan or fan relay, low coolant level or air in the system.
P00B7 — OBD2 code P00B7 flags a problem with the engine cooling and temperature control (engine coolant flow low/performance). Short, gentle driving to a shop is usually possible. Common culprits: wiring faults in the sensor circuit, failed cooling fan or fan relay, low coolant level or air in the system.
P00B8 — P00B8 — MAP - Mass or Volume Air Flow Correlation Bank 2. A fault in the throttle and intake air metering. Short, gentle driving to a shop is usually possible. Typical causes: wiring or connector faults in the throttle circuit, failed electronic throttle motor, dirty throttle body or stuck throttle plate.
P00B9 — Low Pressure Fuel System Pressure - Too Low, Low Ambient Temperature (P00B9): 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, weak fuel pump or clogged fuel filter, faulty fuel pressure regulator.
P00BA — P00BA — Low Fuel Pressure - Forced Limited Power. A fault in the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Typical causes: clogged or leaking fuel injectors, weak fuel pump or clogged fuel filter, contaminated or incorrect fuel.
P00BB — P00BB — Fuel Injector Insufficient Flow - Forced Limited Power. A fault in the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Typical causes: faulty fuel pressure regulator, weak fuel pump or clogged fuel filter, vacuum or intake leaks skewing the mixture.
P00BC — P00BC — Mass or Volume Air Flow "A" Circuit Range/Performance - Air Flow Too Low. 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, open or shorted wiring in the circuit, control module driver fault.
P00BD — Mass or Volume Air Flow "A" Circuit Range/Performance - Air Flow Too High (P00BD): 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, poor ground connection, open or shorted wiring in the circuit.
P00BE — P00BE — Mass or Volume Air Flow "B" Circuit Range/Performance - Air Flow Too Low. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: control module driver fault, corroded, loose or damaged connector, poor ground connection.
P00BF — OBD2 code P00BF flags a problem with the sensor and actuator circuits (mass or volume air flow "B" circuit range/performance - air flow too high). The car is usually drivable while you plan the repair. Common culprits: poor ground connection, control module driver fault, corroded, loose or damaged connector.
P0100 — Mass or Volume Air Flow "A" Circuit Malfunction (P0100): 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, corroded, loose or damaged connector, open or shorted wiring in the circuit.
P0101 — P0101 — Mass or Volume Air Flow "A" Circuit Range/Performance Problem. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: faulty sensor or actuator of the affected circuit, corroded, loose or damaged connector, blown fuse feeding the circuit.
P0102 — P0102 — Mass or Volume Air Flow "A" Circuit Low Input. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: faulty sensor or actuator of the affected circuit, control module driver fault, open or shorted wiring in the circuit.
P0103 — P0103 — Mass or Volume Air Flow "A" Circuit High Input. 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, control module driver fault.
P0104 — Mass or Volume Air Flow "A" Circuit Intermittent (P0104): 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, poor ground connection.
P0105 — Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction (P0105): 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, intake air leaks after the MAF sensor, dirty throttle body or stuck throttle plate.
P0106 — Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem (P0106): 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.
P0107 — OBD2 code P0107 flags a problem with the throttle and intake air metering (manifold absolute pressure/barometric pressure circuit low input). 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.
P0108 — Manifold Absolute Pressure/Barometric Pressure Circuit High Input (P0108): 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, faulty throttle position sensor or pedal sensor.