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

• P1431 — P1431 — Misfire Monitor Profile Reduction Failure. P1431 may be an emissions-monitoring fault, but it can also accompany a real cylinder misfire.
• P1432 — P1432 — Thermostat Heater Control Circuit. P1432 may not cause an immediate driving failure, but an inoperative thermostat heater can affect engine warm-up and temperature control.
• P1433 — OBD2 code P1433 flags a problem with the throttle and intake air metering (EGI mini - MAF failed out of range). Short, gentle driving to a shop is usually possible. Common culprits: contaminated or failed MAF/MAP sensor, faulty throttle position sensor or pedal sensor, intake air leaks after the MAF sensor.
• P1434 — OBD2 code P1434 flags a problem with the throttle and intake air metering (EGI mini - MAF failed short circuit). Short, gentle driving to a shop is usually possible. Common culprits: faulty throttle position sensor or pedal sensor, wiring or connector faults in the throttle circuit, contaminated or failed MAF/MAP sensor.
• P1435 — OBD2 code P1435 flags a problem with the throttle and intake air metering (EGI mini - MAF failed open circuit). Short, gentle driving to a shop is usually possible. Common culprits: dirty throttle body or stuck throttle plate, failed electronic throttle motor, intake air leaks after the MAF sensor.
• P1436 — Electric Air Pump Primary Failure (P1436): 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, control module driver fault.
• P1437 — Electric Air Pump Secondary Failure (P1437): 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, blown fuse feeding the circuit.
• P1439 — P1439 — A/C Refrigerant Temperature Circuit High. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: control module driver fault, blown fuse feeding the circuit, open or shorted wiring in the circuit.
• P1440 — P1440 — A/C Refrigerant Temperature Circuit Range/Performance. 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.
• P1441 — P1441 — A/C Evaporator Air Temperature Circuit Low. A fault in the evaporative emission (EVAP) system. The car is usually drivable while you plan the repair. Typical causes: faulty purge valve (canister purge solenoid), small leak in the fuel tank or filler neck, faulty vent valve or leak detection pump.
• P1442 — P1442 — A/C Evaporator Air Temperature Circuit Range/Performance. A fault in the evaporative emission (EVAP) system. The car is usually drivable while you plan the repair. Typical causes: faulty vent valve or leak detection pump, small leak in the fuel tank or filler neck, saturated or damaged charcoal canister.
• P1443 — OBD2 code P1443 flags a problem with the sensor and actuator circuits (floor temperature switch circuit malfunction). The car is usually drivable while you plan the repair. Common culprits: faulty sensor or actuator of the affected circuit, blown fuse feeding the circuit, control module driver fault.
• P1444 — P1444 — Purge Valve Stuck Open. A fault in the evaporative emission (EVAP) system. The car is usually drivable while you plan the repair. Typical causes: small leak in the fuel tank or filler neck, cracked EVAP hoses or lines, saturated or damaged charcoal canister.
• P1445 — Evaporative Emission (EVAP) System Flow During Non-Purge Chevrolet Only (P1445): a powertrain (engine/transmission) fault affecting the evaporative emission (EVAP) system. The car is usually drivable while you plan the repair. Most often caused by loose, damaged or wrong fuel cap, faulty vent valve or leak detection pump, cracked EVAP hoses or lines.
• P1446 — OBD2 code P1446 flags a problem with the evaporative emission (EVAP) system (evaporative emission (EVAP) system flow during non-purge oldsmobile only). The car is usually drivable while you plan the repair. Common culprits: loose, damaged or wrong fuel cap, saturated or damaged charcoal canister, cracked EVAP hoses or lines.
• P1447 — Evaporative Emission Control System Leak Detected (P1447): a powertrain (engine/transmission) fault affecting the evaporative emission (EVAP) system. The car is usually drivable while you plan the repair. Most often caused by saturated or damaged charcoal canister, small leak in the fuel tank or filler neck, loose, damaged or wrong fuel cap.
• P1448 — Evaporative Emission Control System Control Valve (P1448): a powertrain (engine/transmission) fault affecting the evaporative emission (EVAP) system. The car is usually drivable while you plan the repair. Most often caused by faulty vent valve or leak detection pump, saturated or damaged charcoal canister, loose, damaged or wrong fuel cap.
• P1449 — Purge Flow Sensor Circuit Low Input (P1449): a powertrain (engine/transmission) fault affecting the evaporative emission (EVAP) system. The car is usually drivable while you plan the repair. Most often caused by loose, damaged or wrong fuel cap, faulty purge valve (canister purge solenoid), cracked EVAP hoses or lines.
• P1450 — OBD2 code P1450 flags a problem with the evaporative emission (EVAP) system (purge flow sensor circuit high input). The car is usually drivable while you plan the repair. Common culprits: cracked EVAP hoses or lines, faulty vent valve or leak detection pump, loose, damaged or wrong fuel cap.
• P1451 — Evaporative Vac Solenoid Circuit Malfunction (P1451): a powertrain (engine/transmission) fault affecting the evaporative emission (EVAP) system. The car is usually drivable while you plan the repair. Most often caused by faulty vent valve or leak detection pump, faulty purge valve (canister purge solenoid), loose, damaged or wrong fuel cap.
• P1452 — ELC System Closure Valve Flow Fault (P1452): 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 poor ground connection, faulty sensor or actuator of the affected circuit, open or shorted wiring in the circuit.
• P1453 — P1453 — ELC System 2 Fault. 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, poor ground connection, faulty sensor or actuator of the affected circuit.
• P1454 — OBD2 code P1454 flags a problem with the evaporative emission (EVAP) system (evaporative check solenoid circuit malfunction). The car is usually drivable while you plan the repair. Common culprits: faulty vent valve or leak detection pump, small leak in the fuel tank or filler neck, saturated or damaged charcoal canister.
• P1455 — OBD2 code P1455 flags a problem with the sensor and actuator circuits (unable to bleed up fuel tank vacuum). The car is usually drivable while you plan the repair. Common culprits: open or shorted wiring in the circuit, faulty sensor or actuator of the affected circuit, control module driver fault.