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

• P0691 — Fan 1 Control Circuit Low (P0691): 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, open or shorted wiring in the circuit.
• P0692 — P0692 — Fan 1 Control Circuit High. 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, poor ground connection, control module driver fault.
• P0693 — P0693 — Fan 2 Control Circuit Low. 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, blown fuse feeding the circuit.
• P0694 — OBD2 code P0694 flags a problem with the sensor and actuator circuits (fan 2 control circuit high). The car is usually drivable while you plan the repair. Common culprits: faulty sensor or actuator of the affected circuit, corroded, loose or damaged connector, open or shorted wiring in the circuit.
• P0695 — P0695 — Fan 3 Control Circuit Low. 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, blown fuse feeding the circuit.
• P0696 — Fan 3 Control Circuit High (P0696): 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, blown fuse feeding the circuit.
• P0697 — OBD2 code P0697 flags a problem with the sensor and actuator circuits (sensor reference voltage "C" circuit open). The car is usually drivable while you plan the repair. Common culprits: open or shorted wiring in the circuit, blown fuse feeding the circuit, corroded, loose or damaged connector.
• P0698 — P0698 — Sensor Reference Voltage "C" Circuit 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, blown fuse feeding the circuit.
• P0699 — OBD2 code P0699 flags a problem with the sensor and actuator circuits (sensor reference voltage "C" circuit high). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, blown fuse feeding the circuit, faulty sensor or actuator of the affected circuit.
• P069A — Cylinder 9 Glow Plug Control Circuit Low (P069A): a powertrain (engine/transmission) fault affecting the diesel glow plug system. The car is usually drivable while you plan the repair. Most often caused by damaged glow plug wiring or connector, blown fuse in the glow plug circuit, corroded glow plug connectors.
• P069B — Cylinder 9 Glow Plug Control Circuit High (P069B): a powertrain (engine/transmission) fault affecting the diesel glow plug system. The car is usually drivable while you plan the repair. Most often caused by corroded glow plug connectors, damaged glow plug wiring or connector, faulty glow plug relay or control module.
• P069C — OBD2 code P069C flags a problem with the diesel glow plug system (cylinder 10 glow plug control circuit low). The car is usually drivable while you plan the repair. Common culprits: damaged glow plug wiring or connector, burned-out glow plug, faulty glow plug relay or control module.
• P069D — P069D — Cylinder 10 Glow Plug Control Circuit High. A fault in the diesel glow plug system. The car is usually drivable while you plan the repair. Typical causes: blown fuse in the glow plug circuit, corroded glow plug connectors, faulty glow plug relay or control module.
• P069E — Fuel Pump Control Module Requested MIL Illumination (P069E): 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, vacuum or intake leaks skewing the mixture.
• P069F — OBD2 code P069F flags a problem with the throttle and intake air metering (throttle actuator control lamp control circuit). Short, gentle driving to a shop is usually possible. Common culprits: failed electronic throttle motor, contaminated or failed MAF/MAP sensor, intake air leaks after the MAF sensor.
• P06A0 — P06A0 — Variable A/C Compressor Control Circuit. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: open or shorted wiring in the circuit, poor ground connection, blown fuse feeding the circuit.
• P06A1 — P06A1 — Variable A/C Compressor Control Circuit 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, blown fuse feeding the circuit.
• P06A2 — P06A2 — Variable A/C Compressor Control Circuit High. 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, control module driver fault.
• P06A3 — P06A3 — Sensor Reference Voltage "D" Circuit Open. 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, blown fuse feeding the circuit, poor ground connection.
• P06A4 — P06A4 — Sensor Reference Voltage "D" Circuit Low. 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, blown fuse feeding the circuit.
• P06A5 — Sensor Reference Voltage "D" Circuit High (P06A5): 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 faulty sensor or actuator of the affected circuit, open or shorted wiring in the circuit, blown fuse feeding the circuit.
• P06A6 — P06A6 — Sensor Reference Voltage "A" Circuit Range/Performance. 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, blown fuse feeding the circuit.
• P06A7 — P06A7 — Sensor Reference Voltage "B" Circuit Range/Performance. 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, faulty sensor or actuator of the affected circuit.
• P06A8 — P06A8 — Sensor Reference Voltage "C" 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, poor ground connection, control module driver fault.