Diagnostics

Check Engine Light Flashing vs Solid — What Is the Difference?

A solid check engine light indicates a fault that needs attention. A flashing light means a severe problem that requires immediate action.

The check engine light communicates the severity of a fault through its behaviour. A solid (continuously illuminated) light indicates a fault has been detected — the vehicle may still be drivable, but the problem should be diagnosed and repaired as soon as practical. A flashing check engine light indicates a severe fault that is actively causing damage — typically a misfire that is dumping unburned fuel into the exhaust system. Driving with a flashing light can destroy the catalytic converter and oxygen sensors in a very short distance. If the light is flashing, pull over and have the vehicle recovered to a garage rather than driving it further.