The Check Engine Light or Service Engine Soon Light comes on for many different reasons. Your vehicle’s computer, or ECM (electronic control module), constantly monitors and controls your vehicle’s powertrain (engine and transmission) to keep your vehicle running at maximum efficiency with the least emissions. When your Check Engine Light illuminates, a sensor has determined that something is ‘outside the norm’ for what it is monitoring. This could be your vehicle’s idle, air/fuel mixture or even ignition timing.
When your Check Engine Light first comes on, it could be something very minor. However, if left unchecked, your minor fix could quickly turn into a major repair costing you hundreds or thousands of dollars.
Here’s why: let’s say your Check Engine Light comes on while you’re driving to work. Your vehicle’s ECU has determined that the timing of the spark, called ‘ignition timing’, is off and should be able to adjust the ignition timing automatically. However, if the knocking continues, you may end up destroying your engine. Just think: any ‘knocking’ in any engine usually means metal parts are banging together. Over time, high heat and continual knocking could cause catastrophic engine failure.