Public OBD2 knowledge base
Find and understand OBD2 fault codes.
Enter a code from your diagnostic device. DiagnostiX shows a clear meaning, urgency, likely symptoms, and a structured list of checks.
Enter a code such as P0420, P0300 or U0100.
50 common codes
Public code library
P0100Mass or Volume Air Flow Circuit MalfunctionP0101Mass or Volume Air Flow Circuit Range/PerformanceP0102Mass or Volume Air Flow Circuit Low InputP0103Mass or Volume Air Flow Circuit High InputP0110Intake Air Temperature Sensor Circuit MalfunctionP0113Intake Air Temperature Sensor Circuit High InputP0128Coolant Thermostat Temperature Below Regulating TemperatureP0130Oxygen Sensor Circuit Malfunction Bank 1 Sensor 1P0133Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1P0135Oxygen Sensor Heater Circuit Malfunction Bank 1 Sensor 1P0141Oxygen Sensor Heater Circuit Malfunction Bank 1 Sensor 2P0171System Too Lean Bank 1P0172System Too Rich Bank 1P0174System Too Lean Bank 2P0191Fuel Rail Pressure Sensor Circuit Range/PerformanceP0201Injector Circuit Malfunction Cylinder 1P0234Turbocharger/Supercharger Overboost ConditionP0299Turbocharger/Supercharger Underboost ConditionP0300Random/Multiple Cylinder Misfire DetectedP0301Cylinder 1 Misfire DetectedP0302Cylinder 2 Misfire DetectedP0303Cylinder 3 Misfire DetectedP0304Cylinder 4 Misfire DetectedP0325Knock Sensor 1 Circuit MalfunctionP0335Crankshaft Position Sensor A Circuit MalfunctionP0340Camshaft Position Sensor A Circuit MalfunctionP0401Exhaust Gas Recirculation Flow InsufficientP0402Exhaust Gas Recirculation Flow ExcessiveP0410Secondary Air Injection System MalfunctionP0420Catalyst System Efficiency Below Threshold Bank 1P0430Catalyst System Efficiency Below Threshold Bank 2P0440Evaporative Emission Control System MalfunctionP0441Evaporative Emission Control System Incorrect Purge FlowP0442Evaporative Emission Control System Small Leak DetectedP0446Evaporative Emission Control System Vent Control Circuit MalfunctionP0455Evaporative Emission Control System Gross Leak DetectedP0456Evaporative Emission Control System Very Small Leak DetectedP0500Vehicle Speed Sensor MalfunctionP0505Idle Control System MalfunctionP0562System Voltage LowP0606ECM/PCM Processor FaultP0700Transmission Control System MalfunctionP0715Input/Turbine Speed Sensor Circuit MalfunctionP0720Output Speed Sensor Circuit MalfunctionP0741Torque Converter Clutch Circuit Performance or Stuck OffP2002Diesel Particulate Filter Efficiency Below Threshold Bank 1P2015Intake Manifold Runner Position Sensor Range/Performance Bank 1P2453Diesel Particulate Filter Pressure Sensor Range/PerformanceU0100Lost Communication With ECM/PCMU0121Lost Communication With ABS Control Module
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