All engines codes do not mean an expensive repair, as some indicate minor issues. If engine light stays on, it often means there is an issue that is not an emergency.
If the engine light blinks, It indicates that there is a serious issue that needs immediate attention. Taking the vehicle to a repair shop is the best bet in either situation and a mechanic can use diagnostic tools to determine why the light is one and what code it is showing. Some codes mean minor issues such as low oil or antifreeze. Others mean there is a problem with the brakes or emission system.