Check engine light codes, explained
Your check engine light saves a code like P0420. Find yours below for what it means, what causes it, and what to check first. Many auto parts stores will read the code for free.
- P0300Random/Multiple Cylinder Misfire Detected
- P0301Cylinder 1 Misfire Detected
- P0420Catalyst System Efficiency Below Threshold (Bank 1)
- P0171System Too Lean (Bank 1)
- P0174System Too Lean (Bank 2)
- P0442EVAP System Small Leak Detected
- P0455EVAP System Large Leak Detected
- P0128Coolant Temperature Below Thermostat Regulating Temperature
- P0401Exhaust Gas Recirculation (EGR) Flow Insufficient
- P0500Vehicle Speed Sensor Malfunction
- P0700Transmission Control System Malfunction
- P0115Engine Coolant Temperature Sensor Circuit Malfunction
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