Lets look at maintenance reminder lights and what they mean to you and your car. First off, not all cars and trucks come with them so this may not apply to your vehicle. Looking in your owner’s manual will confirm whether or not this is an issue of concern for you.
For those vehicles that have them, maintenance Lamps will come in one of several forms: a light that says “O2 Sensor”, “Maintenance Due”, “Service due” or something of similar wording.
Diesel vehicles will may display “Air Filter” and/or “timing belt” lights.
Occasionally some vehicles (only pre 1995 models) use the “Check Engine” lamp as a maintenance reminder light as well as a warning for a computer engine control problem. What most of these lights have in common is that they are warning you that a particular part requires service: either by testing the part or replacing the part. It is not a do or die type of warning like the oil lamp, but rather a suggestion to attend to servicing a particular part.
After the service is performed the light must be switched off manually. This can range from a simple procedure of pushing a button, to connecting a scan tool to the engine computer, or removing the instrument panel and changing wiring connections.