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Check engine light- won't go off...

Waterhammer

Waterhammer

NAXJA Forum User
Location
New York, but not really
Check engine light came on the other day. So I hooked it up to my bosses OBD II reader to try and get a code, but nothing showed. We then proceded to try and clear all codes anyway, which it said it did successfully, but the light wouldn't go off. It is a general reader, are there ones Jeep specific? We've used this one on late model chryslers and my jeep is a '00. Should work right. Am I missing something here? The jeep seems to be running fine, but it bothers me I can't reset that switch. I've done some mods- air intake kit, cat back exhaust, throttle body spacer, 7" lift, SYE, driveshaft, etc... Any ideas out there?
 
Is your gas cap on tight? My check engine light came on after I put the cap on crooked when I filled it up. It took a couple of days, but eventually the light turned off.
 
Try disconnecting the battery?

Might be worth a shot anyway.
 
if you are going to disconect the battery you must leave the cables off for 24 hrs, due to newer emession laws the ecu now comes equiped with a back up battery. the mods may be what is causing the light to come on.
 
deadmeat said:
if you are going to disconect the battery you must leave the cables off for 24 hrs, due to newer emession laws the ecu now comes equiped with a back up battery. the mods may be what is causing the light to come on.
Click to expand...

On my 96' it does not have to be 24hrs. I've never heard of the 24hr disconnect thing before.
 
deadmeat said:
if you are going to disconect the battery you must leave the cables off for 24 hrs, due to newer emession laws the ecu now comes equiped with a back up battery. the mods may be what is causing the light to come on.
Click to expand...
I guess it must be a texas thing. IIRC 10 minutes is more then enough, but if you leave them off for 45 then you're really set :D
In regards to the reader: it should have worked. Does it seem to communicate with the ecm and just doesn't return codes or does it show connectivity problems?
 
How many miles,the factory preset service interupt can only be reset at the dealer.
 
RCP Phx said:
How many miles,the factory preset service interupt can only be reset at the dealer.
Click to expand...

That was only the older ones where there was literally a timer box under the dash. Some of the emission stuff in the calif equipped ones have some differences though from what I have read here by owners going thru emissions testing.
 
RichP said:
That was only the older ones where there was literally a timer box under the dash. Some of the emission stuff in the calif equipped ones have some differences though from what I have read here by owners going thru emissions testing.
Click to expand...
I thought the new ones still had like an 80K for the O2 sensor and the cat?
 
The computer hooked up and seemed to be communing with the ECM, it even said all codes were erased. But then the light stayed on. I haven't tried the acc-on thing yet, but I will tonight. The on-off thing didn't work. I'm going to try disconnecting the battery, I'll let you know if that works. I have 115,000 mi on my rig. The last time the light was on was the crank sensor. I have had the light go on for a day but then go off the next and stay off. I think there's a ghost in my wiring harness...
 
Waterhammer said:
The computer hooked up and seemed to be communing with the ECM, it even said all codes were erased. But then the light stayed on. I haven't tried the acc-on thing yet, but I will tonight. The on-off thing didn't work. I'm going to try disconnecting the battery, I'll let you know if that works. I have 115,000 mi on my rig. The last time the light was on was the crank sensor. I have had the light go on for a day but then go off the next and stay off. I think there's a ghost in my wiring harness...
Click to expand...

It could also be those plugs in the back of the panel cluster, usually they result in dead gauges, no odo or trip meter and airbag light on. Usually goes off when hitting bumps or potholes, comes on the same way too..
 
Theres a post back a ways, week or so, about a gauge swap, shows the two big plugs in the back of the cluster, they get dirty and stop working right. Cluster does weird things when this happens..
 
deadmeat said:
if you are going to disconect the battery you must leave the cables off for 24 hrs, due to newer emession laws the ecu now comes equiped with a back up battery. the mods may be what is causing the light to come on.
Click to expand...
maybe a month would work? lmfao!
 
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