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Enter a fault code (like P0420), describe a symptom, or pick a warning light. Get an instant, mechanic-grade answer.
Most-searched fault codes
P0420 — Catalyst System Efficiency Below Threshold (Bank 1)P0171 — System Too Lean (Bank 1)P0300 — Random/Multiple Cylinder Misfire DetectedP0301 — Cylinder 1 Misfire DetectedP0174 — System Too Lean (Bank 2)P0455 — EVAP System Leak Detected (Large Leak)P0442 — EVAP System Leak Detected (Small Leak)P0401 — EGR Insufficient Flow DetectedP0128 — Coolant Thermostat (Below Regulating Temperature)P0101 — Mass Air Flow Sensor Range/PerformanceP0430 — Catalyst System Efficiency Below Threshold (Bank 2)P0440 — EVAP System Malfunction (General)P0135 — O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)P0141 — O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)P0402 — EGR Excessive Flow DetectedP0700 — Transmission Control System MalfunctionP0340 — Camshaft Position Sensor Circuit MalfunctionP0335 — Crankshaft Position Sensor Circuit MalfunctionP0130 — O2 Sensor Circuit Malfunction (Bank 1, Sensor 1)P2195 — O2 Sensor Signal Stuck Lean (Bank 1, Sensor 1)P0011 — "A" Camshaft Position — Timing Over-Advanced (Bank 1)P0014 — "B" Camshaft Position — Timing Over-Advanced (Bank 1)P0325 — Knock Sensor Circuit Malfunction (Bank 1)P0118 — Engine Coolant Temperature Sensor Circuit HighP2187 — System Too Lean at Idle (Bank 1)P0500 — Vehicle Speed Sensor (VSS) MalfunctionP0131 — O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)P0137 — O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)P0133 — O2 Sensor Slow Response (Bank 1, Sensor 1)P0021 — "A" Camshaft Position — Timing Over-Advanced (Bank 2)P0117 — Engine Coolant Temperature Sensor Circuit LowP2189 — System Too Lean at Idle (Bank 2)P2293 — Fuel Pressure Regulator 2 PerformanceU0100 — Lost Communication With ECM/PCM "A"P0012 — "A" Camshaft Position — Timing Over-Retarded (Bank 1)P0341 — Camshaft Position Sensor "A" Circuit Range/Performance (Bank 1)P0113 — Intake Air Temperature Sensor 1 Circuit High (Bank 1)P0506 — Idle Air Control System RPM Lower Than ExpectedP0507 — Idle Air Control System RPM Higher Than ExpectedP0456 — EVAP System Leak Detected (Very Small Leak)
More flagship codes (P0174, P0455, P0442, P0401, P0128, P0101…) are being published — prioritized by real-world fault frequency.
Browse by symptom
Engine MisfireRough IdleCheck Engine Light FlashingLoss of PowerPoor Fuel EconomyEngine StallingHard StartingEngine OverheatingCar Won’t Start (Battery OK)Engine KnockingWhite Smoke From ExhaustBlack Smoke From ExhaustTransmission SlippingCar Shaking at IdleHigh Idle RPMJerking During AccelerationFuel Smell in the CarCold-Start StallingSlow Acceleration / Lack of PowerVibration While Driving