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

• B2528 — B2528 — Left Rear Stop lamp Circuit Short to Battery. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: damaged wiring in door jambs or wet areas, blown fuse or failed relay, corroded or loose connectors.
• B2529 — OBD2 code B2529 flags a problem with the body electrical system (left rear turn lamp circuit failure). The car is usually drivable while you plan the repair. Common culprits: blown fuse or failed relay, faulty switch, motor or actuator of the affected system, damaged wiring in door jambs or wet areas.
• B2530 — Left Rear Turn Lamp Circuit Short to Battery (B2530): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by corroded or loose connectors, damaged wiring in door jambs or wet areas, blown fuse or failed relay.
• B2531 — Right Rear Backup Lamp Circuit Failure (B2531): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by corroded or loose connectors, faulty switch, motor or actuator of the affected system, damaged wiring in door jambs or wet areas.
• B2532 — B2532 — Right Rear Backup Lamp Circuit Short to Battery. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: body control module (BCM) fault, damaged wiring in door jambs or wet areas, corroded or loose connectors.
• B2533 — Right Rear Stop lamp Circuit Failure (B2533): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by body control module (BCM) fault, damaged wiring in door jambs or wet areas, blown fuse or failed relay.
• B2534 — OBD2 code B2534 flags a problem with the body electrical system (right rear stop lamp circuit short to battery). The car is usually drivable while you plan the repair. Common culprits: blown fuse or failed relay, faulty switch, motor or actuator of the affected system, body control module (BCM) fault.
• B2535 — B2535 — Right Rear Turn Lamp Circuit Failure. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: damaged wiring in door jambs or wet areas, faulty switch, motor or actuator of the affected system, corroded or loose connectors.
• B2536 — B2536 — Right Rear Turn Lamp Circuit Short to Battery. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: body control module (BCM) fault, faulty switch, motor or actuator of the affected system, corroded or loose connectors.
• B2539 — B2539 — Aux A/C Mode Position Reference Circuit Short to Ground. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: faulty switch, motor or actuator of the affected system, corroded or loose connectors, blown fuse or failed relay.
• B2540 — B2540 — Aux A/C Mode Position Reference Circuit Short to Battery. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: corroded or loose connectors, faulty switch, motor or actuator of the affected system, damaged wiring in door jambs or wet areas.
• B2543 — B2543 — Aux A/C Control Switch Reference Circuit Short to Ground. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: faulty switch, motor or actuator of the affected system, body control module (BCM) fault, corroded or loose connectors.
• B2544 — OBD2 code B2544 flags a problem with the body electrical system (aux A/C control switch reference circuit short to battery). The car is usually drivable while you plan the repair. Common culprits: body control module (BCM) fault, damaged wiring in door jambs or wet areas, faulty switch, motor or actuator of the affected system.
• B2545 — OBD2 code B2545 flags a problem with the body electrical system (system power relay circuit short to battery). The car is usually drivable while you plan the repair. Common culprits: blown fuse or failed relay, corroded or loose connectors, body control module (BCM) fault.
• B2546 — System Power Relay Circuit Failure (B2546): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by blown fuse or failed relay, damaged wiring in door jambs or wet areas, corroded or loose connectors.
• B2550 — LAMP DOME OUTPUT Circuit Short to Ground (B2550): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by blown fuse or failed relay, corroded or loose connectors, body control module (BCM) fault.
• B2553 — Disable Signal Output Circuit Short to Battery (B2553): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by damaged wiring in door jambs or wet areas, faulty switch, motor or actuator of the affected system, body control module (BCM) fault.
• B2554 — LAMP DOME OUTPUT Circuit Failure (B2554): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by blown fuse or failed relay, body control module (BCM) fault, faulty switch, motor or actuator of the affected system.
• B2555 — LAMP DOME OUTPUT Circuit Short to Battery (B2555): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by body control module (BCM) fault, blown fuse or failed relay, corroded or loose connectors.
• B2556 — Enable Signal Circuit Short to Battery (B2556): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by faulty switch, motor or actuator of the affected system, blown fuse or failed relay, body control module (BCM) fault.
• B2557 — OBD2 code B2557 flags a problem with the body electrical system (left power sliding door open/close output circuit short to battery). The car is usually drivable while you plan the repair. Common culprits: corroded or loose connectors, blown fuse or failed relay, body control module (BCM) fault.
• B2558 — Right Power Sliding Door Open/Close Output Circuit Short to Battery (B2558): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by blown fuse or failed relay, body control module (BCM) fault, damaged wiring in door jambs or wet areas.
• B2559 — OBD2 code B2559 flags a problem with the body electrical system (aux A/C blower motor relay circuit short to battery). The car is usually drivable while you plan the repair. Common culprits: corroded or loose connectors, damaged wiring in door jambs or wet areas, faulty switch, motor or actuator of the affected system.
• B2560 — B2560 — Aux A/C Blower Motor Relay Circuit Short to Ground. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: faulty switch, motor or actuator of the affected system, corroded or loose connectors, blown fuse or failed relay.