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Need some help! Check engine light!

B

Bobbo

NAXJA Forum User
Location
Bismarck ND 58504
I have a 98 XJ with a 4.0, and 230,000 miles and I am getting a code of air idle control valve. Had a guy scan it, (at the auto center where I work) but he says they need to run OEM tests on the system and his scan tool wont do it. I replaced the valve with a OEM piece, the light went off for a couple minutes but came back on again. Before I replaced the valve/sensor? it would not start without giving it a little gas, and would not idle very well till it warmed up , now it starts and idles ok (could maybe use plugs and wires) but the check engine light is on constantly. Still showing the same code as it did before and the guy cant get it to clear. I really dont want to take it to a dealership. cause I figure the collective minds here are smarter than the tech at a dealership. Any help would be great, this is my DD so for now I am stuck with a 78 cherokee FSJ with 35 inch tires and a 401--not a good MPG!
(I still cant wait to lift this XJ these things can really wheel!)
Thanks again!
 
I think... sometimes it takes awhile for the codes to clear --even though the problem has been fixed--
Or.... the codes may have to be "reset" by someone with an OBD II reader... and then if the problem is truly fixed, it won't come back again... Good Luck!
 
Unplug the black connector from the ECU under the hood for a few minutes. This will clear the ECU's memory so you will know if the problem is fixed or not.
 
Bobbo said:
I have a 98 XJ with a 4.0, and 230,000 miles and I am getting a code of air idle control valve. Had a guy scan it, (at the auto center where I work) but he says they need to run OEM tests on the system and his scan tool wont do it. I replaced the valve with a OEM piece, the light went off for a couple minutes but came back on again. Before I replaced the valve/sensor? it would not start without giving it a little gas, and would not idle very well till it warmed up , now it starts and idles ok (could maybe use plugs and wires) but the check engine light is on constantly. Still showing the same code as it did before and the guy cant get it to clear. I really dont want to take it to a dealership. cause I figure the collective minds here are smarter than the tech at a dealership. Any help would be great, this is my DD so for now I am stuck with a 78 cherokee FSJ with 35 inch tires and a 401--not a good MPG!
(I still cant wait to lift this XJ these things can really wheel!)
Thanks again!
Click to expand...
If the light went off and came back that means that you sitll have a problem. Check wiring, check the valve (you might have gotten a bad one). You can also clear codes by disconnecting battery for a few minutes (15?20?).
 
Well, heres what happened, the tech first cleaned the sensor up and cleared the code then test drove it, and it was fine. About an hour later I hop in it and the light came right back on and it was still missing at idle and would not idle without help. So I got a mopar sensor, unplug the battery and install the new sensor. Wait half hour, reconnect battery and it runs great, take off for home and the light comes back on about a half hour later. But is still runs great. Take it in to clear the code again the next day and it comes right back on again. A week later still have a light and it still runs and starts good.
 
Bobbo said:
Well, heres what happened, the tech first cleaned the sensor up and cleared the code then test drove it, and it was fine. About an hour later I hop in it and the light came right back on and it was still missing at idle and would not idle without help. So I got a mopar sensor, unplug the battery and install the new sensor. Wait half hour, reconnect battery and it runs great, take off for home and the light comes back on about a half hour later. But is still runs great. Take it in to clear the code again the next day and it comes right back on again. A week later still have a light and it still runs and starts good.
Click to expand...
Something I just remembered that was mentioned here before, was that on the newer ones with 2 o2 sensors, if you replace one you need to also replace the other as well as one old one new makes one of them go out.
 
Kejtar said:
Something I just remembered that was mentioned here before, was that on the newer ones with 2 o2 sensors, if you replace one you need to also replace the other as well as one old one new makes one of them go out.
Click to expand...
The code is the idle air control valve--and thats what I replaced
 
Did you take some carb cleaner and spray in where the IAC went and cleaned out all the crud? If not, you probably wasted your money on the IAC.
 
old_man said:
Did you take some carb cleaner and spray in where the IAC went and cleaned out all the crud? If not, you probably wasted your money on the IAC.
Click to expand...
I dont know if the tech did that or not, I didnt but I will try that. Thanks!
 
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