Check Engine Light On? Here's What It Means & How to Fix It

The check engine light (CEL) is your vehicle's way of telling you something is wrong with the engine, emissions, or fuel system. It can indicate anything from a loose gas cap to a failing catalytic converter.

Common Causes

• Faulty Oxygen (O2) Sensor — Codes P0130, P0131, P0133, P0135
• Loose or Damaged Gas Cap — Codes P0440, P0442, P0455
• Catalytic Converter Failure — Codes P0420, P0430
• Mass Air Flow (MAF) Sensor — Codes P0100, P0101, P0102
• Failing Fuel Injectors — Codes P0201-P0208
• Spark Plug or Ignition Coil Failure — Codes P0300-P0308

Frequently Asked Questions

Can I drive with the check engine light on? If steady, yes — drive to a mechanic. If flashing, pull over immediately.

How much does it cost to fix? From $0 (gas cap) to $1,000+ (catalytic converter).