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

• P0B2B — P0B2B — Hybrid Battery "C" Voltage. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: poor ground connection, open or shorted wiring in the circuit, corroded, loose or damaged connector.
• P0B2C — P0B2C — Hybrid Battery "C" Voltage Unstable. 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, corroded, loose or damaged connector.
• P0B2D — P0B2D — Hybrid Battery "C" Voltage Low. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: poor ground connection, corroded, loose or damaged connector, control module driver fault.
• P0B2E — OBD2 code P0B2E flags a problem with the sensor and actuator circuits (hybrid battery "C" voltage high). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, poor ground connection, corroded, loose or damaged connector.
• P0B2F — P0B2F — Hybrid Battery "D" Voltage. 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.
• P0B30 — OBD2 code P0B30 flags a problem with the sensor and actuator circuits (hybrid battery "D" voltage unstable). The car is usually drivable while you plan the repair. Common culprits: blown fuse feeding the circuit, faulty sensor or actuator of the affected circuit, open or shorted wiring in the circuit.
• P0B31 — OBD2 code P0B31 flags a problem with the sensor and actuator circuits (hybrid battery "D" voltage low). The car is usually drivable while you plan the repair. Common culprits: open or shorted wiring in the circuit, corroded, loose or damaged connector, faulty sensor or actuator of the affected circuit.
• P0B32 — P0B32 — Hybrid Battery "D" Voltage 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, control module driver fault, poor ground connection.
• P0B33 — OBD2 code P0B33 flags a problem with the sensor and actuator circuits (high voltage service disconnect circuit). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, open or shorted wiring in the circuit, poor ground connection.
• P0B34 — P0B34 — High Voltage Service Disconnect Circuit Performance. 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, control module driver fault, poor ground connection.
• P0B35 — High Voltage Service Disconnect Circuit Low (P0B35): 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, poor ground connection.
• P0B36 — High Voltage Service Disconnect Circuit High (P0B36): 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, control module driver fault, poor ground connection.
• P0B37 — OBD2 code P0B37 flags a problem with the sensor and actuator circuits (high voltage service disconnect open). The car is usually drivable while you plan the repair. Common culprits: poor ground connection, corroded, loose or damaged connector, faulty sensor or actuator of the affected circuit.
• P0B38 — OBD2 code P0B38 flags a problem with the engine cooling and temperature control (motor electronics coolant pump "B" control circuit/open). Short, gentle driving to a shop is usually possible. Common culprits: low coolant level or air in the system, failed cooling fan or fan relay, wiring faults in the sensor circuit.
• P0B39 — P0B39 — Motor Electronics Coolant Pump "B" Control Circuit Low. A fault in the engine cooling and temperature control. Short, gentle driving to a shop is usually possible. Typical causes: wiring faults in the sensor circuit, failed cooling fan or fan relay, faulty coolant temperature sensor.
• P0B3A — OBD2 code P0B3A flags a problem with the engine cooling and temperature control (motor electronics coolant pump "B" control circuit high). Short, gentle driving to a shop is usually possible. Common culprits: faulty coolant temperature sensor, low coolant level or air in the system, failed cooling fan or fan relay.
• P0B3B — P0B3B — Hybrid Battery Voltage Sense "A" Circuit. 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, faulty sensor or actuator of the affected circuit, open or shorted wiring in the circuit.
• P0B3C — Hybrid Battery Voltage Sense "A" Circuit Range/Performance (P0B3C): 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, corroded, loose or damaged connector.
• P0B3D — P0B3D — Hybrid Battery Voltage Sense "A" Circuit Low. 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, control module driver fault.
• P0B3E — P0B3E — Hybrid Battery Voltage Sense "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, blown fuse feeding the circuit.
• P0B3F — P0B3F — Hybrid Battery Voltage Sense "A" Circuit Intermittent/Erratic. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: poor ground connection, open or shorted wiring in the circuit, blown fuse feeding the circuit.
• P0B40 — Hybrid Battery Voltage Sense "B" Circuit (P0B40): 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, blown fuse feeding the circuit.
• P0B41 — Hybrid Battery Voltage Sense "B" Circuit Range/Performance (P0B41): 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, poor ground connection, corroded, loose or damaged connector.
• P0B42 — Hybrid Battery Voltage Sense "B" Circuit Low (P0B42): 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, corroded, loose or damaged connector, blown fuse feeding the circuit.