Clearing Engine light after repair???

[drizler]

I was getting a p302 code indicating a bad plug so changed them all to some decent bosch platinums. The code immediately signed p302 done but the damned engine light is still there. How long does it take to go away or what is the reset procecure? I have to get this done so it will pass that new cursed NYS inspection. Thanks>>

[xj31]

That code doesn't actually mean you have a bad plug,it means there is a number 2 cylinder misfire.It might be caused by the plug but it can also be caused by a coil,an injector,an engine problem,bad fuel or even a bad pcm.It might have been an intermittent misfire that you never figure out.How does it run now?was it running rough before you changed the plugs and if that is the case did changing the plugs fix it? Anyways there are a couple of ways to turn the light off.One way is to drive it for a few days and if the problem is in fact fixed the light will turn off when the pcm sees the required "good trips".Another way is to have the codes cleared with a scan tool or you could even just disconnect the battery for a few minutes and when you reconnect it the light should be off.Now I don't know about your inspection ,but here in Illinois,if you clear the codes and go for the emission inspection right away,you will get rejected because it will not be in "Carb Readiness".Basically, the system has to run some tests or monitors to make sure that everything is ok,like O2 Sensor Heater Monitor,Evaporative Leak Detection Monitor,Catalyst Monitor,O2 Sensor Monitor,and Purge Monitor.When you clear the codes it resets all of those to having not been run.It usually takes a couple of days at least to get those monitors to run because the engine has to be operating within specific parameters or they will not run.This may not be applicable in your case but I kind of think it might be if you are worried about the light.

[drizler]

My wife dug that p302 sparkplug info up on the internet and humble me who has been fixing my own everything for 30 years from airplanes to bulldozers didn't really buy it. I never heard of a complete diagnostic link to that overhead console like she described. It flies in the face of the manufacutrers desire to get you back there for more $$$. Another thing new ( to me) is that shitty inspection which goes directly to the dmv via internet ( post 96 models). Boy they are gonna drool over that one $$$. This is going to amount to the greatest screwing of the generl public since the annual private aircraft inspection. I am going to hang right on to my old stuff until the dust settles with this new process.
Luckily for me this is the only post 96 vehicle I have and a handy piece of black tape cures all the other check engine lights woes that arent "real". For the record I changed those plugs a week ago and that jeep now has about 500 miles on it with 20-30 start stop cycles so I will try pulling the battery post to end that thing. When I do that with my Z24 it takes a few days to figure out how to idle right but its easier than screwing with the idle relearn process. Anyways thanks for the info on how this thing really works.