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

• C1499 — OBD2 code C1499 flags a problem with the sensor and actuator circuits (transfer case contact plate "A" encoder circuit failure). The car is usually drivable while you plan the repair. Common culprits: poor ground connection, blown fuse feeding the circuit, faulty sensor or actuator of the affected circuit.
• C1500 — Transfer Case Contact Plate "B" Encoder Circuit Failure (C1500): a chassis (brakes/steering/suspension) 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, open or shorted wiring in the circuit.
• C1501 — OBD2 code C1501 flags a problem with the sensor and actuator circuits (transfer case contact plate "C" encoder circuit failure). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, faulty sensor or actuator of the affected circuit, poor ground connection.
• C1502 — OBD2 code C1502 flags a problem with the sensor and actuator circuits (transfer case contact plate "D" encoder circuit failure). The car is usually drivable while you plan the repair. Common culprits: poor ground connection, faulty sensor or actuator of the affected circuit, corroded, loose or damaged connector.
• C1503 — C1503 — Dynamic Stability Control Left Front Valve Malfunction. A fault in the ABS / stability control. Short, gentle driving to a shop is usually possible. Typical causes: damaged sensor wiring or corroded connector, faulty ABS module or pump motor, failed wheel speed sensor.
• C1504 — Dynamic Stability Control Right Front Valve Malfunction (C1504): a chassis (brakes/steering/suspension) fault affecting the ABS / stability control. Short, gentle driving to a shop is usually possible. Most often caused by blown fuse or low voltage to the ABS module, damaged tone (reluctor) ring on the hub, faulty ABS module or pump motor.
• C1505 — OBD2 code C1505 flags a problem with the ABS / stability control (dynamic stability control left rear valve malfunction). Short, gentle driving to a shop is usually possible. Common culprits: damaged sensor wiring or corroded connector, faulty ABS module or pump motor, damaged tone (reluctor) ring on the hub.
• C1506 — Dynamic Stability Control Right Rear Valve Malfunction (C1506): a chassis (brakes/steering/suspension) fault affecting the ABS / stability control. Short, gentle driving to a shop is usually possible. Most often caused by failed wheel speed sensor, damaged sensor wiring or corroded connector, faulty ABS module or pump motor.
• C1507 — OBD2 code C1507 flags a problem with the ABS / stability control (traction control of brake exceeds time-out). Short, gentle driving to a shop is usually possible. Common culprits: damaged sensor wiring or corroded connector, blown fuse or low voltage to the ABS module, damaged tone (reluctor) ring on the hub.
• C1508 — Traction Control of Engine Exceeds Time-Out (C1508): a chassis (brakes/steering/suspension) fault affecting the ABS / stability control. Short, gentle driving to a shop is usually possible. Most often caused by damaged sensor wiring or corroded connector, faulty ABS module or pump motor, damaged tone (reluctor) ring on the hub.
• C1510 — C1510 — Right Front Wheel Pressure Reduction Performance Problem. 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.
• C1511 — C1511 — Left Front Wheel Pressure Reduction Performance Problem. 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.
• C1512 — C1512 — Right Rear Wheel Pressure Reduction Performance Problem. 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, poor ground connection, control module driver fault.
• C1513 — C1513 — Left rear Wheel Pressure Reduction Performance Problem. 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.
• C1515 — OBD2 code C1515 flags a problem with the sensor and actuator circuits (C1515 — lateral accelerometer open/short or disorientation: causes, symptoms & fix). The car is usually drivable while you plan the repair. Common culprits: blown fuse feeding the circuit, open or shorted wiring in the circuit, control module driver fault.
• C1516 — C1516 — Roll Rate Sensor Signal Fault: Causes, Symptoms & Fix (C1516): a vehicle 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, open or shorted wiring in the circuit, control module driver fault.
• C1517 — OBD2 code C1517 flags a problem with the sensor and actuator circuits (C1517 — roll rate sensor circuit failure: causes, symptoms & fix). The car is usually drivable while you plan the repair. Common culprits: blown fuse feeding the circuit, control module driver fault, open or shorted wiring in the circuit.
• C1518 — OBD2 code C1518 flags a problem with the sensor and actuator circuits (C1518 — red fault warning lamp indicator short to battery: causes, symptoms & fix). The car is usually drivable while you plan the repair. Common culprits: open or shorted wiring in the circuit, poor ground connection, blown fuse feeding the circuit.
• C1519 — C1519 — C1519 — Red Fault Warning Lamp Indicator Circuit Failure: Causes, Symptoms & Fix. 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, blown fuse feeding the circuit.
• C1520 — OBD2 code C1520 flags a problem with the sensor and actuator circuits (C1520 — delta-s plausibility failure: causes, symptoms & fix). 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, corroded, loose or damaged connector.
• C1521 — OBD2 code C1521 flags a problem with the sensor and actuator circuits (C1521 — delta-s circuit failure: causes, symptoms & fix). The car is usually drivable while you plan the repair. Common culprits: open or shorted wiring in the circuit, poor ground connection, control module driver fault.
• C1522 — OBD2 code C1522 flags a problem with the ABS / stability control (C1522 — brake pedal travel sensor internal power supply failure: causes, symptoms & fix). Short, gentle driving to a shop is usually possible. Common culprits: damaged tone (reluctor) ring on the hub, faulty ABS module or pump motor, damaged sensor wiring or corroded connector.
• C1523 — OBD2 code C1523 flags a problem with the ABS / stability control (C1523 — brake fluid level sensor out of range: causes, symptoms & fix). Short, gentle driving to a shop is usually possible. Common culprits: damaged tone (reluctor) ring on the hub, faulty ABS module or pump motor, blown fuse or low voltage to the ABS module.
• C1524 — C1524 — Brake Pedal Travel Sensor Calibration Incomplete: Causes, Symptoms & Fix (C1524): a vehicle fault affecting the ABS / stability control. Short, gentle driving to a shop is usually possible. Most often caused by damaged sensor wiring or corroded connector, damaged tone (reluctor) ring on the hub, faulty ABS module or pump motor.