A dictionary of the most common diagnostic trouble codes: what they mean, their symptoms, causes, and whether you can keep driving.
Codes by make and engineRandom/Multiple Cylinder Misfire Detected
Cylinder 1 Misfire Detected
Catalyst System Efficiency Below Threshold (Bank 1)
System Too Lean (Bank 1)
EVAP System Leak Detected (Small Leak)
EVAP System Leak Detected (Large Leak)
Coolant Temperature Below Thermostat Regulating Temperature
EGR Flow Insufficient
Turbocharger Underboost
Camshaft Position Sensor Circuit Malfunction
Crankshaft/Camshaft Position Correlation (Bank 1 Sensor A)
Camshaft Position Timing Over-Advanced (Bank 1)
Intake Air Temperature Sensor Circuit High
Mass Air Flow Sensor Range/Performance
Vehicle Speed Sensor Malfunction
Transmission Control System Malfunction
System Voltage Low
Fuel Rail/System Pressure Too Low
Fuel Pressure Regulator Control Circuit Low
Glow Plug Module Control Circuit (Diesel)
Diesel Particulate Filter Efficiency Below Threshold
Turbocharger Overboost Condition
Lost Communication With ECM/PCM
Engine Control System Malfunction (ABS/VSC Interlock - Toyota/Lexus)
Cylinder-Specific Misfire (P0302, P0303, P0304, P0305, P0306)
Catalyst Efficiency Below Threshold (Bank 2)
System Too Lean (Bank 2)
Crankshaft Position Sensor Circuit Malfunction
Mass Air Flow Sensor Circuit Low
O2 Sensor Heater Circuit (Bank 1 Sensor 2)
Knock Sensor Circuit Malfunction
Idle Control System RPM Lower Than Expected
Torque Converter Clutch Circuit Performance
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Descriptions are for guidance only. Accurate diagnosis requires a workshop inspection.
