OBD-II Error Code Knowledge Hub

A comprehensive list of common Powertrain (P-codes) to help you diagnose your check engine light.

P00xx - Fuel and Air Metering and Auxiliary Emission Controls

This series relates to the fuel and air systems.

P0011"A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 1)
P0012"A" Camshaft Position - Timing Over-Retarded (Bank 1)
P01xx - Fuel and Air Metering

These codes relate to sensors and systems that control the air-fuel ratio.

P0101Mass or Volume Air Flow Circuit Range/Performance Problem
P0135O2 Sensor Heater Circuit (Bank 1 Sensor 1)
P0171System Too Lean (Bank 1)
P0172System Too Rich (Bank 1)
P0174System Too Lean (Bank 2)
P02xx - Fuel and Air Metering (Injector Circuit)

These codes relate to the fuel injector circuits.

P0201Injector Circuit/Open - Cylinder 1
P0202Injector Circuit/Open - Cylinder 2
P03xx - Ignition System or Misfire

These codes indicate a problem with the engine's combustion, often requiring immediate attention.

P0300Random/Multiple Cylinder Misfire Detected
P0301Cylinder 1 Misfire Detected
P0302Cylinder 2 Misfire Detected
P0340Camshaft Position Sensor Circuit Malfunction
P04xx - Auxiliary Emissions Controls

This is a broad category for emissions systems like the catalytic converter, EVAP, and EGR systems.

P0401EGR Flow Insufficient
P0420Catalyst System Efficiency Below Threshold (Bank 1)
P0430Catalyst System Efficiency Below Threshold (Bank 2)
P0440EVAP System Malfunction
P0442EVAP System Leak Detected (Small Leak)
P0455EVAP System Leak Detected (Large Leak)
P05xx - Vehicle Speed, Idle Control, and Auxiliary Inputs

These codes relate to vehicle speed and idle control systems.

P0500Vehicle Speed Sensor (VSS) Malfunction
P0505Idle Air Control System Malfunction