Check Engine Light

I'm not sure from your post if what you mean is that it simply flashed then went out, or has come on and is staying on. The OBD II system on your '97 takes a number of inputs and should any of them go out of spec for a given duration it will turn on the light. If it goes back into spec the light may go back out on its own, or could "latch" requiring you to visit a dealer to have it turned off. The fault could be as simple as a loose gas cap, or as serious as a failed engine component, ther Feds want you suitably alarmed enough to take it back to a dealer for inspection, therefore they wont agree to have it read "emissions fault" or anything less alarming than "check engine". FWIW, the issues are rarely anything fatal.

the same thing happened to my friend's card. he just disconnected one of the battery poles and reconnected. the light is off since then. it sounds stupid but it worked.. he said if there is a real problem, it will come on again.. /topac

Yup, that works.

A loose gas cap can set the light off.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

osu wrote:

Thx, Guys! Will try the battery trick and check the gas cap,etc. Will report back results.

BTW, it's really freaking me out that when I check this thread from work via Google Groups that suddenly my post becomes number 163(!!) in the thread "Check Engine Light" and the original poster was a guy who'd just bought a '97 TJ, "three weeks ago" and was having the same problem ! Original post date was 8-10-97 !! Weirdness on the newsgroups.

Andrew

Whenever my "check engine" light has come on around the 60k~70k mile mark, I've found it's time to replace the O2 sensor. If the other fixes don't help, you might try it. It's a $60 part needs to be changed about now anyway.

L.A. Jeepster did pass the time by typing:

FWIW, I've found that a smooth idle while warming up and otherwise good power followd by piss poor stumbly idle is usually caused by a "lazy" O2 sensor. Reason being the O2 sensor isn't used for warmup just idle and cruise, and at cruise your engine is more forgiving about the mix.

Try googleing on that subject and you find quite a few references.

I guess you are referring to the upstream o2 sensor. Where do you find one for $60? Most everyone where I live want $80 cal

Cal did pass the time by typing:

My 93 only has one, but yes, the downstream O2 sensor on all models to date only monitor the catalytic converter. (least that's what the manuals say)

Got the part online. $69 from

and possibley (both are dealers so the parts are OEM)

$56 from

(Sometimes you get what you pay for, dunno, claims OEM)

Hey Guys,

For some reason this thread is all messed up. My at-home ISP doesn't show it and the connect through Google at work still places this thread as originating in 1997(!). All this has made it very hard for me to follow all comments.

Anyway,... The battery cable disconnect trick worked. Check Engine Light is out and hasn't returned in several days. Big Thanks! for that.

Andrew

I believe the manuals say the downstream O2 is used to monitor the cat. I don't think it says that's all it's used for. :-)

Could be, but the only DTCs I've seen are for the cat. Possibly it could keep an eye on the primary O2 sensor based on what gets through the cat.

Actually I think it's used for making the EPA happy and to provide more sales to the O2 sensor makers. :)

It's also used for fuel trim, and rationality checks.

Probably that too. :-)