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Check engine light codes

Plain-English meanings, causes, and repair costs for the most common OBD-II trouble codes.

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Emissions / Exhaust

P0420Catalyst System Efficiency Below Threshold (Bank 1)P0430Catalyst System Efficiency Below Threshold (Bank 2)

Ignition / Engine

P0300Random/Multiple Cylinder Misfire DetectedP0301Cylinder 1 Misfire DetectedP0302Cylinder 2 Misfire DetectedP0303Cylinder 3 Misfire DetectedP0304Cylinder 4 Misfire DetectedP0305Cylinder 5 Misfire DetectedP0306Cylinder 6 Misfire Detected

Fuel / Air Metering

P0171System Too Lean (Bank 1)P0174System Too Lean (Bank 2)P0172System Too Rich (Bank 1)P0175System Too Rich (Bank 2)

EVAP / Emissions

P0442Evaporative Emission System Leak Detected (Small Leak)P0455Evaporative Emission System Leak Detected (Large Leak)P0456Evaporative Emission System Leak Detected (Very Small Leak)P0457Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)P0441Evaporative Emission System Incorrect Purge FlowP0446Evaporative Emission System Vent Control Circuit MalfunctionP0496Evaporative Emission System Flow During a Non-Purge Condition

Cooling

P0128Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

EGR / Emissions

P0401Exhaust Gas Recirculation Flow Insufficient Detected

Variable Valve Timing

P0011Intake Camshaft Position Timing - Over-Advanced or System Performance (Bank 1)P0014Exhaust Camshaft Position Timing - Over-Advanced or System Performance (Bank 1)

Engine Timing

P0016Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor A)P0017Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor B)

Air Metering

P0101Mass or Volume Air Flow Circuit Range/PerformanceP0102Mass or Volume Air Flow Circuit Low Input

Sensors

P0113Intake Air Temperature Sensor 1 Circuit High

Sensors / Cooling

P0118Engine Coolant Temperature Circuit High

Throttle Control

P0121Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance

Oxygen Sensors

P0133O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)P0135O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)P0141O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)P0155O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)

Ignition / Sensors

P0325Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor)

Engine Sensors

P0335Crankshaft Position Sensor A Circuit MalfunctionP0340Camshaft Position Sensor A Circuit Malfunction (Bank 1 or Single Sensor)

Sensors / Transmission

P0500Vehicle Speed Sensor A Malfunction

Idle Control

P0505Idle Air Control System MalfunctionP0507Idle Air Control System RPM Higher Than Expected

Transmission

P0700Transmission Control System MalfunctionP0715Input/Turbine Speed Sensor A Circuit MalfunctionP0720Output Speed Sensor Circuit MalfunctionP0741Torque Converter Clutch Circuit Performance or Stuck OffP0750Shift Solenoid A Malfunction

Engine Computer

P0606Control Module Processor Fault

Charging System

P0562System Voltage Low

Fuel / Emissions

P2096Post Catalyst Fuel Trim System Too Lean (Bank 1)

Turbo / Boost

P0299Turbocharger/Supercharger A Underboost Condition