What I say on brake repair
A check engine light usually indicates that the onboard diagnostics check has discovered an improperly working component that must be taken care of immediately to avoid permanent damage to your system. Do not ignore an illuminated check engine light. In late model cars, the check engine light behaves differently depending on the severity of the problem. A blinking or red check engine light indicates an issue so critical that immediate attention is warranted. A steady check engine light indicates that a non emergency exists and should be checked out as soon as possible.