Free OBD-II codes and vehicle diagnostics

Look up any trouble code and get an answer for your exact vehicle. Every page tells you what the code means, how urgent it is, what typically causes it, and what a repair costs. No account, no paywall, and nothing in front of the answer.

Common trouble codes

P0010Camshaft Position Actuator Circuit (Bank 1)P0011Camshaft Position Timing Over-Advanced (Bank 1)P0014Camshaft Position Timing Over-Advanced (Bank 1 Exhaust)P0016Crankshaft Position — Camshaft Position Correlation (Bank 1 Sensor A)P0030HO2S Heater Control Circuit (Bank 1 Sensor 1)P0031HO2S Heater Control Circuit Low (Bank 1 Sensor 1)P0100Mass or Volume Air Flow Circuit MalfunctionP0101Mass or Volume Air Flow Circuit Range/PerformanceP0102Mass or Volume Air Flow Circuit Low InputP0110Intake Air Temperature Circuit MalfunctionP0113Intake Air Temperature Sensor Circuit High InputP0117Engine Coolant Temperature Circuit Low InputP0118Engine Coolant Temperature Circuit High InputP0120Throttle Pedal Position Sensor A Circuit MalfunctionP0121Throttle Position Sensor A Circuit Range/PerformanceP0128Coolant Thermostat Below Regulating TemperatureP0130O2 Sensor Circuit Malfunction (Bank 1 Sensor 1)P0131O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)P0135O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)P0136O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)P0138O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)P0140O2 Sensor Circuit No Activity (Bank 1 Sensor 2)P0141O2 Heater Circuit Malfunction (Bank 1 Sensor 2)P0150O2 Sensor Circuit Malfunction (Bank 2 Sensor 1)P0171System Too Lean (Bank 1)P0172System Too Rich (Bank 1)P0174System Too Lean (Bank 2)P0217Engine Over Temperature ConditionP0299Turbocharger/Supercharger UnderboostP0300Random/Multiple Cylinder Misfire DetectedP0301Cylinder 1 Misfire DetectedP0302Cylinder 2 Misfire DetectedP0303Cylinder 3 Misfire DetectedP0304Cylinder 4 Misfire DetectedP0325Knock Sensor 1 Circuit Malfunction (Bank 1)P0335Crankshaft Position Sensor A Circuit MalfunctionP0340Camshaft Position Sensor Circuit MalfunctionP0401Exhaust Gas Recirculation Flow InsufficientP0420Catalyst System Efficiency Below Threshold (Bank 1)P0430Catalyst System Efficiency Below Threshold (Bank 2)P0442Evaporative Emission System Leak Detected (Small Leak)P0446Evaporative Emission System Vent Control CircuitP0455Evaporative Emission System Leak Detected (Large Leak)P0480Cooling Fan 1 Control CircuitP0507Idle Air Control System RPM Higher Than ExpectedP0562System Voltage LowP0700Transmission Control System MalfunctionU0100Lost Communication With ECM/PCM A

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Reference