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.

P0466 — Purge Flow Sensor Circuit Range/Performance (P0466): 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 small leak in the fuel tank or filler neck, cracked EVAP hoses or lines, faulty purge valve (canister purge solenoid).
P0467 — Purge Flow Sensor Circuit Low Input (P0467): 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 cracked EVAP hoses or lines, faulty vent valve or leak detection pump, loose, damaged or wrong fuel cap.
P0468 — Purge Flow Sensor Circuit High Input (P0468): 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 cracked EVAP hoses or lines, saturated or damaged charcoal canister, faulty vent valve or leak detection pump.
P0469 — Purge Flow Sensor Circuit Intermittent (P0469): 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, saturated or damaged charcoal canister.
P046A — P046A — Catalyst Temperature Sensor 1/2 Correlation (Bank 1). A fault in the catalytic converter efficiency monitoring. The car is usually drivable while you plan the repair. Typical causes: exhaust leak ahead of the converter, persistent rich or lean fuel mixture, oil or coolant entering the exhaust.
P046B — OBD2 code P046B flags a problem with the catalytic converter efficiency monitoring (catalyst temperature sensor 1/2 correlation (bank 2)). The car is usually drivable while you plan the repair. Common culprits: engine misfires damaging the catalyst, exhaust leak ahead of the converter, aged or contaminated catalytic converter.
P046C — Exhaust Gas Recirculation Sensor "A" Circuit Range/Performance (P046C): a powertrain (engine/transmission) fault affecting the exhaust gas recirculation (EGR) system. The car is usually drivable while you plan the repair. Most often caused by faulty EGR solenoid or wiring, carbon buildup blocking the EGR valve or passages, failed EGR valve or position sensor.
P046D — P046D — Exhaust Gas Recirculation Sensor "A" Circuit Intermittent/Erratic. A fault in the exhaust gas recirculation (EGR) system. The car is usually drivable while you plan the repair. Typical causes: vacuum leaks in EGR control lines, faulty EGR solenoid or wiring, failed EGR valve or position sensor.
P046E — OBD2 code P046E flags a problem with the exhaust gas recirculation (EGR) system (exhaust gas recirculation sensor "B" circuit range/performance). The car is usually drivable while you plan the repair. Common culprits: ECM control circuit fault, failed EGR valve or position sensor, vacuum leaks in EGR control lines.
P046F — OBD2 code P046F flags a problem with the exhaust gas recirculation (EGR) system (exhaust gas recirculation sensor "B" circuit intermittent/erratic). The car is usually drivable while you plan the repair. Common culprits: vacuum leaks in EGR control lines, ECM control circuit fault, faulty EGR solenoid or wiring.
P0470 — P0470 — Exhaust Pressure Sensor "A" Circuit. 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, open or shorted wiring in the circuit, corroded, loose or damaged connector.
P0471 — P0471 — Exhaust Pressure Sensor "A" Circuit Range/Performance. 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, faulty sensor or actuator of the affected circuit.
P0472 — OBD2 code P0472 flags a problem with the sensor and actuator circuits (exhaust pressure sensor "A" circuit low). 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, poor ground connection.
P0473 — Exhaust Pressure Sensor "A" Circuit High (P0473): 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, faulty sensor or actuator of the affected circuit, open or shorted wiring in the circuit.
P0474 — Exhaust Pressure Sensor "A" Circuit Intermittent (P0474): 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, faulty sensor or actuator of the affected circuit, corroded, loose or damaged connector.
P0475 — Exhaust Pressure Control Valve "A" (P0475): 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, poor ground connection, control module driver fault.
P0476 — Exhaust Pressure Control Valve "A" Range/Performance (P0476): 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, open or shorted wiring in the circuit, corroded, loose or damaged connector.
P0477 — Exhaust Pressure Control Valve "A" Low (P0477): 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 control module driver fault, faulty sensor or actuator of the affected circuit, poor ground connection.
P0478 — Exhaust Pressure Control Valve "A" High (P0478): 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, poor ground connection, faulty sensor or actuator of the affected circuit.
P0479 — OBD2 code P0479 flags a problem with the sensor and actuator circuits (exhaust pressure control valve "A" intermittent). The car is usually drivable while you plan the repair. Common culprits: poor ground connection, faulty sensor or actuator of the affected circuit, open or shorted wiring in the circuit.
P047A — OBD2 code P047A flags a problem with the sensor and actuator circuits (exhaust pressure sensor "B" circuit). The car is usually drivable while you plan the repair. Common culprits: faulty sensor or actuator of the affected circuit, poor ground connection, control module driver fault.
P047B — Exhaust Pressure Sensor "B" Circuit Range/Performance (P047B): 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 open or shorted wiring in the circuit, faulty sensor or actuator of the affected circuit, poor ground connection.
P047C — OBD2 code P047C flags a problem with the sensor and actuator circuits (exhaust pressure sensor "B" circuit low). The car is usually drivable while you plan the repair. Common culprits: faulty sensor or actuator of the affected circuit, open or shorted wiring in the circuit, corroded, loose or damaged connector.
P047D — OBD2 code P047D flags a problem with the sensor and actuator circuits (exhaust pressure sensor "B" circuit high). The car is usually drivable while you plan the repair. Common culprits: open or shorted wiring in the circuit, corroded, loose or damaged connector, blown fuse feeding the circuit.