Hello,

Does anyone know how to reset the check engine light on a 98 Jeep Grand Cherokee Ltd? I was having a problem with one of my spark plug wires and while driving the "Check Engine" light came on. I've since replaced the wire but the light is still on. I need to get it off.

Oh, and I can't find the manual for the vehicle....Thanks.

 

Autozone has scan tools you can use in thier lot, you have to leave your D/L while you use it but it saves you alot of $$$$

 

or you could try disconecting the batt. over night.

 

You can get codes scanned at Autozone, but they will not clear them for you (depending in the person, he/she may hand the scanner to you and allow you to clear them).

The other option is to buy your own scanner and do it yourself (they have come down in price considerably since I got mine). Basically, all you do is hook the scanner into the OBD II jack, turn the key to on, clear codes (it should be explained in the instructions). It is quite easy.

 

Thanks put the light went off by itself.

After changing the faulty wire, I drove it for a day and this morning I noticed the light was off!

Cool.

 

Light will usually clear itself after 50 or so starts without the problem present.

 

Your vehicle is what is called OBD 2 compliant (newer than 1995). This means that the light will go off after it is tested 3 consecutive times and passes all 3 of them. The test will only run 1 time per trip. Therefore, you will need to drive this at least 3 times after it is fixed before the light will go out. The information on how the vehicle was being driven, when it needed repair, will stay in the computer for 40 warm up cycles. That can be a long time. The idea behind that is if a problem happened once or twice and you could not get in for repair. The information would still be in the computer to tell the technician how to drive the vehicle to reduplicate the problem.
I hope this helps.

 

Not sure if this would work w/obdII or not, but w/the obdI in the Mazda MX6 or similar, what has been done is to disconnect the Neg batt terminal and hold down the brake pedel for about 30secs...this clears the ECU and after driving it for a bit, the ecu will re-set/calibrate and all should be good.
That's what Ive heard and read.

 

The required number of drive cycles required to reset the light depends on the fault. But by the same principal, it must pass the test on a specific number of trips in order to do so. The information will remain in the computers memory as a stored code and the data that was present at the time the code was set will remain in what is called a freeze frame. This is all information that can be obtained by the use of a diagnostic scan tool. Not all code readers at the auto parts stores have this capability. If you plan to purchase a scanner, by all means know what you are buying first.
Billy