Why Does My Check Engine Light Flash? When your Check Engine Light Flashes this is an indication of a serious issue with your engine. While sometimes it can be as simple as changing out the Spark Plugs and Wires or Coils depending on what the vehicle has. On the other hand, it can be more serious and take dedicated equipment to find the issue. One of the first things we do is hook a scan tool to the diagnostic port of the vehicle to look for clues. Depending on what we find we may have to hook our lab scope to the wires at the sensors or the ECM to check signal integrity. If all that looks good, we use pressure sensors in the cylinder, intake manifold and exhaust pipe to find the mechanical issues in the engine. This equipment can find burnt valves, bad timing belts and broken piston rings as well as a lot of other mechanical issues with out a lot of time spent taking the engine apart. If your Check Engine Light is Flashing or on give us a call and we would be more than happy to help you out with your Check Engine Light problems.