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

• P1290 — OBD2 code P1290 flags a problem with the sensor and actuator circuits (cylinder head over temp sensed). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, corroded, loose or damaged connector, faulty sensor or actuator of the affected circuit.
• P1291 — P1291 — Fuel Pulse In Range But Lower Than Expected. 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.
• P1292 — P1292 — Fuel Pulse In Range But Higher Than Expected. 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, faulty sensor or actuator of the affected circuit.
• P1293 — Cylinder Head Temp Sensor Out Of Self Test Range (P1293): 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, control module driver fault, poor ground connection.
• P1294 — P1294 — Cylinder Head Temp Sensor High Input. 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, blown fuse feeding the circuit, poor ground connection.
• P1295 — OBD2 code P1295 flags a problem with the sensor and actuator circuits (cylinder head temp sensor low input). The car is usually drivable while you plan the repair. Common culprits: poor ground connection, corroded, loose or damaged connector, control module driver fault.
• P1296 — OBD2 code P1296 flags a problem with the fuel delivery and mixture control (injector high side short to GND or VBATT - bank 1). Short, gentle driving to a shop is usually possible. Common culprits: faulty fuel rail pressure sensor or wiring, vacuum or intake leaks skewing the mixture, faulty fuel pressure regulator.
• P1297 — P1297 — Injector High Side Short To GND Or VBATT - Bank 2. A fault in the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Typical causes: clogged or leaking fuel injectors, faulty fuel pressure regulator, weak fuel pump or clogged fuel filter.
• P1298 — OBD2 code P1298 flags a problem with the fuel delivery and mixture control (injector high side open - bank 1). Short, gentle driving to a shop is usually possible. Common culprits: contaminated or incorrect fuel, vacuum or intake leaks skewing the mixture, clogged or leaking fuel injectors.
• P1299 — Injector High Side Open - Bank 2/Target idle not reached (P1299): 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 clogged or leaking fuel injectors, vacuum or intake leaks skewing the mixture, weak fuel pump or clogged fuel filter.
• P1300 — Multi-faults - Bank 1 - With Low Side Shorts (P1300): 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, corroded, loose or damaged connector, blown fuse feeding the circuit.
• P1301 — P1301 — Multi-faults - Bank 2 - With Low Side Shorts. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: control module driver fault, blown fuse feeding the circuit, corroded, loose or damaged connector.
• P1302 — OBD2 code P1302 flags a problem with the fuel delivery and mixture control (injector high sides shorted together). Short, gentle driving to a shop is usually possible. Common culprits: vacuum or intake leaks skewing the mixture, weak fuel pump or clogged fuel filter, clogged or leaking fuel injectors.
• P1303 — IDM Failure (P1303): 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.
• P1304 — OBD2 code P1304 flags a problem with the engine cooling and temperature control (cylinder head overtemperature protection active). Short, gentle driving to a shop is usually possible. Common culprits: failed cooling fan or fan relay, wiring faults in the sensor circuit, water pump or radiator issues.
• P1305 — P1305 — Boost Calibration Fault. A fault in the turbocharger / supercharger boost control. Short, gentle driving to a shop is usually possible. Typical causes: clogged intake or exhaust (DPF/cat), stuck wastegate or faulty boost control solenoid, worn turbocharger.
• P1306 — P1306 — Boost Calibration High. A fault in the turbocharger / supercharger boost control. Short, gentle driving to a shop is usually possible. Typical causes: vacuum or actuator line damage, stuck wastegate or faulty boost control solenoid, faulty boost pressure sensor.
• P1307 — P1307 — Boost Calibration Low. A fault in the turbocharger / supercharger boost control. Short, gentle driving to a shop is usually possible. Typical causes: clogged intake or exhaust (DPF/cat), stuck wastegate or faulty boost control solenoid, worn turbocharger.
• P1309 — EGR Calibration High (P1309): a powertrain (engine/transmission) fault affecting the exhaust gas recirculation (EGR) system. The car is usually drivable while you plan the repair. Most often caused by vacuum leaks in EGR control lines, faulty EGR solenoid or wiring, failed EGR valve or position sensor.
• P1310 — P1310 — ECM Ionization-Miss Detection Fault. P1310 can accompany incomplete combustion or a misfire, so it should be diagnosed promptly.
• P1311 — P1311 — ECM ionization-monitoring communication failure. If the engine runs smoothly, P1311 can usually be driven cautiously to a repair facility.
• P1312 — P1312 — Timer Control Valve Circuit Malfunction. If P1312 is the only code and the engine runs smoothly, avoid hard acceleration and arrange diagnosis soon.
• P1313 — EGR Calibration Low (P1313): a powertrain (engine/transmission) fault affecting the exhaust gas recirculation (EGR) system. The car is usually drivable while you plan the repair. Most often caused by carbon buildup blocking the EGR valve or passages, faulty EGR solenoid or wiring, vacuum leaks in EGR control lines.
• P1315 — Kickdown Relay Hold Circuit Fault (P1315): 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, control module driver fault, open or shorted wiring in the circuit.