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.

P0A99 — Hybrid Battery Pack Cooling Fan 2 Control Circuit Low (P0A99): 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 thermostat stuck open or closed, wiring faults in the sensor circuit, water pump or radiator issues.
P0A9A — OBD2 code P0A9A flags a problem with the engine cooling and temperature control (hybrid battery pack cooling fan 2 control circuit high). Short, gentle driving to a shop is usually possible. Common culprits: low coolant level or air in the system, thermostat stuck open or closed, water pump or radiator issues.
P0A9B — Hybrid Battery Temperature Sensor "A" Circuit (P0A9B): 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.
P0A9C — Hybrid Battery Temperature Sensor "A" Range/Performance (P0A9C): 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, poor ground connection.
P0A9D — Hybrid Battery Temperature Sensor "A" Circuit Low (P0A9D): 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, blown fuse feeding the circuit.
P0A9E — P0A9E — Hybrid Battery Temperature Sensor "A" Circuit High. 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, corroded, loose or damaged connector, poor ground connection.
P0A9F — P0A9F — Hybrid Battery Temperature Sensor "A" Circuit Intermittent/Erratic. 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, faulty sensor or actuator of the affected circuit.
P0AA0 — Hybrid Battery Positive Contactor Circuit (P0AA0): 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, control module driver fault.
P0AA1 — Hybrid Battery Positive Contactor Circuit Stuck Closed (P0AA1): 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.
P0AA2 — OBD2 code P0AA2 flags a problem with the sensor and actuator circuits (hybrid battery positive contactor circuit stuck open). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, open or shorted wiring in the circuit, faulty sensor or actuator of the affected circuit.
P0AA3 — Hybrid Battery Negative Contactor Circuit (P0AA3): 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, corroded, loose or damaged connector, control module driver fault.
P0AA4 — P0AA4 — Hybrid Battery Negative Contactor Circuit Stuck Closed. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: control module driver fault, open or shorted wiring in the circuit, blown fuse feeding the circuit.
P0AA5 — OBD2 code P0AA5 flags a problem with the sensor and actuator circuits (hybrid battery negative contactor circuit stuck open). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, blown fuse feeding the circuit, poor ground connection.
P0AA6 — Hybrid Battery Voltage System Isolation Fault (P0AA6): 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.
P0AA7 — Hybrid Battery Voltage Isolation Sensor Circuit (P0AA7): 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, poor ground connection.
P0AA8 — P0AA8 — Hybrid Battery Voltage Isolation Sensor 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, poor ground connection, faulty sensor or actuator of the affected circuit.
P0AA9 — OBD2 code P0AA9 flags a problem with the sensor and actuator circuits (hybrid battery voltage isolation sensor circuit low). The car is usually drivable while you plan the repair. Common culprits: open or shorted wiring in the circuit, control module driver fault, blown fuse feeding the circuit.
P0AAA — OBD2 code P0AAA flags a problem with the sensor and actuator circuits (hybrid battery voltage isolation sensor circuit high). The car is usually drivable while you plan the repair. Common culprits: faulty sensor or actuator of the affected circuit, poor ground connection, open or shorted wiring in the circuit.
P0AAB — P0AAB — Hybrid Battery Voltage Isolation Sensor Circuit Intermittent/Erratic. 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, poor ground connection.
P0AAC — P0AAC — Hybrid Battery Pack Air Temperature Sensor "A" 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, control module driver fault, blown fuse feeding the circuit.
P0AAD — P0AAD — 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, open or shorted wiring in the circuit, poor ground connection.
P0AAE — P0AAE — Hybrid Battery Pack Air Temperature Sensor "A" 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.
P0AAF — P0AAF — Hybrid Battery Pack Air Temperature Sensor "A" Circuit High P0AB0 Intermittent/Erratic. 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.
P0AB1 — P0AB1 — Hybrid Battery Pack Air Temperature Sensor "B" 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, blown fuse feeding the circuit, poor ground connection.