The Check Engine light is an amber colored indicator on the instrument panel of your vehicle that notifies the driver of malfunctions in the vehicles engine control computer. It should light up any time you turn the ignition key to the on position and go out a few seconds after starting the engine. If it stays on after starting that means there is a problem. If it starts flashing it means there’s a severe problem that needs to be addressed immediately.
The Check Engine Light should illuminate briefly when you turn the ignition key to the on position without starting the engine. Always check for this when buying a used car to avoid “hidden” problems.
Understanding Diagnostic Trouble Codes (DTC's)
A Diagnostic Trouble Code (DTC) is the code stored in your vehicles computer when it detects a fault. These codes help a the technician to identify the type of fault and the sub-system the fault occurred in. If you ever pull in to a shop with a check engine light and the staff simply reads the codes and immediately gives you a diagnosis be wary. There are specific troubleshooting procedures for each individual code and without following those procedures the best you can expect to get is an educated guess.
Many times when the Check Engine Light comes on the cause is‘just a sensor’. It’s important to note that every sensor that can cause the light to illuminate performs a vital engine control function. ‘It’s just a sensor’ for your car is like saying ‘it’s just an eye’ for your body.
Reading codes vs Diagnosing faults
Many auto parts stores now offer to read the trouble codes stored in your vehicles engine computer when a malfunction occurs. Some can even provide a list of possible failed parts that can cause those codes. Keep in mind that most parts store employees don’t have the training or equipment to perform a complete diagnostic but they may be able to give you some idea of the kind of problem your vehicle has. The only way to identify the exact failure is to have a complete diagnostic ran by a professional technician.
A flashing Check Engine Light indicates a severe malfunction that may lead to damage of critical engine components. If you notice this light flashing repeatedly while driving call us immediately.
Image Credit: checkenginelight.png has been modified for use on this site. The original image Motorkontrollleuchte.svg was released into the public domain courtesy of its author, wikipedia user Chris828 at the German Wikipedia project.