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.

P0228 — OBD2 code P0228 flags a problem with the throttle and intake air metering (throttle/pedal position sensor/switch c circuit high input). Short, gentle driving to a shop is usually possible. Common culprits: faulty throttle position sensor or pedal sensor, wiring or connector faults in the throttle circuit, intake air leaks after the MAF sensor.
P0229 — OBD2 code P0229 flags a problem with the throttle and intake air metering (throttle/pedal position sensor/switch c circuit intermittent). Short, gentle driving to a shop is usually possible. Common culprits: dirty throttle body or stuck throttle plate, wiring or connector faults in the throttle circuit, failed electronic throttle motor.
P022A — OBD2 code P022A flags a problem with the sensor and actuator circuits (charge air cooler bypass control "A" circuit open). The car is usually drivable while you plan the repair. Common culprits: poor ground connection, open or shorted wiring in the circuit, corroded, loose or damaged connector.
P022B — Charge Air Cooler Bypass Control "A" Circuit Low (P022B): 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, open or shorted wiring in the circuit, blown fuse feeding the circuit.
P022C — OBD2 code P022C flags a problem with the sensor and actuator circuits (charge air cooler bypass control "A" circuit high). The car is usually drivable while you plan the repair. Common culprits: faulty sensor or actuator of the affected circuit, blown fuse feeding the circuit, poor ground connection.
P022D — P022D — Charge Air Cooler Bypass Control "B" Circuit Open. 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, open or shorted wiring in the circuit, faulty sensor or actuator of the affected circuit.
P022E — P022E — Charge Air Cooler Bypass Control "B" 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, poor ground connection, open or shorted wiring in the circuit.
P022F — OBD2 code P022F flags a problem with the sensor and actuator circuits (charge air cooler bypass control "B" circuit high). The car is usually drivable while you plan the repair. Common culprits: faulty sensor or actuator of the affected circuit, control module driver fault, poor ground connection.
P0230 — P0230 — Fuel Pump Primary Circuit Malfunction. A fault in the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Typical causes: faulty fuel rail pressure sensor or wiring, vacuum or intake leaks skewing the mixture, faulty fuel pressure regulator.
P0231 — P0231 — Fuel Pump Secondary Circuit Low. A fault in the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Typical causes: weak fuel pump or clogged fuel filter, contaminated or incorrect fuel, clogged or leaking fuel injectors.
P0232 — OBD2 code P0232 flags a problem with the fuel delivery and mixture control (fuel pump secondary circuit high). Short, gentle driving to a shop is usually possible. Common culprits: clogged or leaking fuel injectors, vacuum or intake leaks skewing the mixture, faulty fuel pressure regulator.
P0233 — OBD2 code P0233 flags a problem with the fuel delivery and mixture control (fuel pump secondary circuit intermittent). Short, gentle driving to a shop is usually possible. Common culprits: faulty fuel rail pressure sensor or wiring, contaminated or incorrect fuel, weak fuel pump or clogged fuel filter.
P0234 — P0234 — Engine Turbocharger/Supercharger Overboost Condition. A fault in the turbocharger / supercharger boost control. Short, gentle driving to a shop is usually possible. Typical causes: vacuum or actuator line damage, worn turbocharger, boost leak in intercooler piping or hoses.
P0235 — OBD2 code P0235 flags a problem with the turbocharger / supercharger boost control (turbocharger boost sensor a circuit malfunction). Short, gentle driving to a shop is usually possible. Common culprits: worn turbocharger, clogged intake or exhaust (DPF/cat), stuck wastegate or faulty boost control solenoid.
P0236 — P0236 — Turbocharger Boost Sensor A Circuit Range/Performance. A fault in the turbocharger / supercharger boost control. Short, gentle driving to a shop is usually possible. Typical causes: worn turbocharger, vacuum or actuator line damage, faulty boost pressure sensor.
P0237 — OBD2 code P0237 flags a problem with the turbocharger / supercharger boost control (turbocharger boost sensor a circuit low). Short, gentle driving to a shop is usually possible. Common culprits: stuck wastegate or faulty boost control solenoid, boost leak in intercooler piping or hoses, clogged intake or exhaust (DPF/cat).
P0238 — Turbocharger Boost Sensor A Circuit High (P0238): a powertrain (engine/transmission) fault affecting the turbocharger / supercharger boost control. Short, gentle driving to a shop is usually possible. Most often caused by clogged intake or exhaust (DPF/cat), faulty boost pressure sensor, worn turbocharger.
P0239 — OBD2 code P0239 flags a problem with the turbocharger / supercharger boost control (turbocharger boost sensor b circuit malfunction). Short, gentle driving to a shop is usually possible. Common culprits: stuck wastegate or faulty boost control solenoid, faulty boost pressure sensor, vacuum or actuator line damage.
P023A — Charge Air Cooler Coolant Pump Control Circuit Open (P023A): 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 low coolant level or air in the system, thermostat stuck open or closed, failed cooling fan or fan relay.
P023B — P023B — Charge Air Cooler Coolant Pump Control Circuit Low. A fault in the engine cooling and temperature control. Short, gentle driving to a shop is usually possible. Typical causes: water pump or radiator issues, failed cooling fan or fan relay, wiring faults in the sensor circuit.
P023C — P023C — Charge Air Cooler Coolant Pump Control Circuit High. 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, low coolant level or air in the system, water pump or radiator issues.
P023D — P023D — Manifold Absolute Pressure - Turbocharger/Supercharger Boost Sensor "A" Correlation. A fault in the turbocharger / supercharger boost control. Short, gentle driving to a shop is usually possible. Typical causes: stuck wastegate or faulty boost control solenoid, worn turbocharger, vacuum or actuator line damage.
P023E — Manifold Absolute Pressure - Turbocharger/Supercharger Boost Sensor "B" Correlation (P023E): a powertrain (engine/transmission) fault affecting the turbocharger / supercharger boost control. Short, gentle driving to a shop is usually possible. Most often caused by clogged intake or exhaust (DPF/cat), vacuum or actuator line damage, worn turbocharger.
P023F — Fuel Pump Secondary Circuit/Open (P023F): 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 weak fuel pump or clogged fuel filter, contaminated or incorrect fuel, faulty fuel rail pressure sensor or wiring.