SCANMYCAR
OBD-II code library

Check-engine codes, explained honestly

What each code means, whether it's safe to keep driving, what the live sensor data shows, and what actually fixes it - cheapest first. In-depth guides for the codes people actually search.

P0420 Catalyst System Efficiency Below Threshold (Bank 1) Drive normally - check soon P0171 Fuel Trim System Lean (Bank 1) Get it checked soon P0300 Random/Multiple Cylinder Misfire Detected Caution P0430 Catalyst System Efficiency Below Threshold (Bank 2) Drive normally - check soon P0128 Coolant Thermostat Malfunction Drive normally - check soon P0455 Evaporative Emission Control System Leak Detected (gross leak) Drive normally - check soon P0174 Fuel Trim too Lean (Bank 2) Get it checked soon P0301 Cylinder 1 Misfire Detected Caution P0442 Evaporative Emission Control System Leak Detected (small leak) Drive normally - check soon P0011 "A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 1) Get it checked soon P0113 Intake Air Temperature Circuit High Input Drive normally - check soon P0303 Cylinder 3 Misfire Detected Caution P0016 Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor A) Caution P0102 Mass or Volume Air Flow Circuit Low Input Get it checked soon P0401 Exhaust Gas Recirculation Flow Insufficient Detected Get it checked soon P0325 Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor) Get it checked soon U0100 Lost Communication With ECM/PCM "A" Caution P0131 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1) Get it checked soon P0700 Transmission Control System Malfunction Get it checked soon P0715 Input/Turbine Speed Sensor Circuit Malfunction Get it checked soon

By symptom

No code yet, or a warning light that acts up? Start with what the car does. All symptom guides

Check engine light flashing Why it flashes, what to do in the next ten minutes, and what the misfire counts show. Slow down now. Stop driving soon.

Looking for a code that isn't here? These guides cover the twenty most-searched codes in depth. The app ships the full database of 483 OBD-II codes and reads them from every module of your car - and the AI mechanic (part of Pro) can explain yours against your car's actual live data.

Codes and live sensors are free in the app

Read it on your own car

ScanMyCar reads your car's codes, with stored, pending and permanent codes from every module, the freeze frame and 139 live sensors, and explains them in plain words. Trouble codes and live sensors are free. Obie, the AI mechanic, is part of ScanMyCar Pro.

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OBD-II Scanner $34.99 regular price $49 Preorder