2002 Ford Explorer-service engine soon light is on. How do I reset it?

To reset the light after a repair, you can either take the vehicle to a garage with an OBDII scanner, buy an OBDII scanner for about 50 bucks from harbor freight and reset it yourself, or simply pull the battery terminals off for a while. The computer requires power to remember the error codes. Removing the battery will kill the computer and reset the codes. Depending on your system, the vehicle may also need to relearn its idle and various operating parameters. It will do this on its own after a few minutes of run time, but you may need to sit in the vehicle and hold the throttle at an idle until the computer relearns the idle. The manufactures make sure that a power loss will not affect the systems in any significant manner to avoid problems caused by dead batteries, which happen frequently. If the problem is truly fixed, the light will stay off until the computer senses a new problem. If the problem is still present, the light will come back on after you drive the vehicle for a while. If you do your own mechanical work, the OBDII reader is worth having for diagonstic purposes, but it is not required to reset the check engine soon light. Either way you reset the computer, and you will have to drive the vehicle for a while to allow the computer to run its on board diagnostics.

If the DELTA PRESSURE FEEDBACK EXHAUST sensor was the cause of the light, it should reset itself after 2 or 3 complete ignition cycles. If you don't mind having to reset all the monitors you can simply remove a battery cable for a few seconds but that will also make you lose your clock or anything that has a memory that's defendant on constant battery voltage.

You can try disconnecting the battery for a couple of minutes and see if that will do the trick. Other wise you will need a code reader or a scan tool to clear the codes.

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