Check-engine codes
What does my check-engine code mean?
Plain-English explanations for OBD-II trouble codes: what the code means, the most likely causes, symptoms, and how much labour a repair usually takes.
Most-searched codes
- P0420Catalyst System Efficiency Below Threshold (Bank 1)
- P0300Random/Multiple Cylinder Misfire Detected
- P0171System Too Lean (Bank 1)
- P0442Evaporative Emission System Leak Detected (Small Leak)
- P0455Evaporative Emission System Leak Detected (Large Leak)
- P0128Coolant Thermostat Below Regulating Temperature
- P0401Exhaust Gas Recirculation Flow Insufficient Detected
- P0301Cylinder 1 Misfire Detected
- P0174System Too Lean (Bank 2)
- P0440Evaporative Emission Control System Malfunction
- P0456Evaporative Emission System Leak Detected (Very Small Leak)
- P0135O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
- P0113Intake Air Temperature Sensor High Input
- P0101Mass or Volume Air Flow Circuit Range/Performance
- P0340Camshaft Position Sensor "A" Circuit (Bank 1 or Single Sensor)
- P0335Crankshaft Position Sensor "A" Circuit Malfunction
- P0700Transmission Control System Malfunction
- P0500Vehicle Speed Sensor "A" Malfunction
- P0507Idle Air Control System RPM Higher Than Expected
- P0325Knock Sensor 1 Circuit Malfunction (Bank 1)
B0xxxBody323 codesC0xxxChassis626 codesP0xxxPowertrain (generic)3,705 codesP2xxxPowertrain (generic, extended)3,495 codesP3xxxPowertrain (manufacturer / generic)155 codesU0xxxNetwork1,055 codesU3xxxNetwork (extended)174 codes
Code data: OBDex open dataset (CC0), reviewed and rewritten for drivers. Always confirm a diagnosis before replacing parts.