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1997 -- Another CEL Thread -- I Searched

J

javajeep

NAXJA Forum User
Location
Arkansas
I want to start this post by saying that I searched -- for a long time. I want to know how to get the codes off my heep from home.

1. I have done this before. At least I think I did. Am I getting mad cow? I am certain I did this last year.

2. I have read a lot of threads on here saying it can not be done for a 1997. I am sure I did this before.

3. I learned how to do it from a post on this website -- I have searched a long time -- I can not find it.

OK -- now to my CEL problem:

I went to autozone. Yes -- they do it for free, but I want to be able to do it from home. I have an O2 sensor code. It is the only code. Because it is the only code, it was suggested that the sensor was probably bad. I bought one for $65.

I have two concerns. The old one looks like it has a lot of rust/crud on it. Should I be concerned about problems with getting it out?

My second concern is that after reading this thread:

http://www.naxja.org/forum/showthread.php?t=913555&highlight=check+codes+procedure

I am wondering if the problem is the gas cap. What kind of code is caused by faulty gas cap? Is there actually a specific code for the gas cap, or is it diagnosed indirectly by an emissions code?

Thanks for all of your help.
 
First of all, do you have any symptoms to go along with the code?

The oxygen sensor code shouldn't have tripped for a bad or loose gas cap, that trips when unburned hydrocarbons are sensed and the code would have something to do with evaporative emission control system I believe; not sure exactly what code number though that you would see offhand.

I suspect that you may have developed a "lazy" oxygen sensor that happens with age. Many times, the lazy ones will set a code but not have symptoms as the computer can still compensate for it.

As for pulling the codes, I have never been able to do it with the key-on, key off procedure on my 99. It is my understanding the OBD2 systems can't be accessed that way. And yes, I have heard of people that said they could do it but I personally have never seen it happen. There is a "self test" that may trip with key on key off cycles but I've never seen actual codes pulled.
 
Sounds like you have a bad O2 sensor. I've replaced several over the years. You can check it per service manuel procedure.
Sorry I don't remember the procedure but ,its listed in the service manuel.

Good Luck

Nick
 
javajeep said:
The old one looks like it has a lot of rust/crud on it. Should I be concerned about problems with getting it out?
Click to expand...
Just get a big wrench on it and go for it, it will be tight but on something like that you can just use brute force and don't have to worry about much.
 
Yes, you can read codes directly on a '97 XJ with a key-on/key-off procedure described here: http://www.go.jeep-xj.info/HowtoECUcodes.htm. This works, at least it does on my '97 XJ.

Having said that, it's not all that helpful on a '97 since you'll get the generic 2-digit codes like "21" for O2 sensor circuit. This doesn't tell you upstream vs downstream sensor, short to high-voltage, heater circuit malfunction, etc. For these specific (and much more helpful) OBD-II codes, you'll need a real OBD-II scanner. If you got the actual P-code from AutoZone, it would be helpful if you posted it if you wanted to get some meaningful input about your problem. Otherwise, it's just a guess.

-Ed Rico
 
Ed Rico said:
Yes, you can read codes directly on a '97 XJ with a key-on/key-off procedure described here: http://www.go.jeep-xj.info/HowtoECUcodes.htm. This works, at least it does on my '97 XJ.
-Ed Rico
Click to expand...

Very interesting.

I just went out and tried the recommended trip reset/key on key off technique described in that link for my 1999.

It ran what appears to be a "self-test" as different lights for different systems (cruise, 4WD, etc) came and went. Also the odometer shows a count-up from 1-9. However, it didn't appear to access any codes, even an end code.

From what I can tell from this post, the info in this link and from your information Ed, I'm wondering if 96-97 vehicles work with the key-on technique but XJ's newer than that don't?? But as you mention, two digit codes are not that helpful. Just another reason to buy a code reader I guess!

If anybody has any definitive information on where the cutoff (what year) is for successful operation of these key-on/key off procedures, I'd be interested to hear how it shakes out.
 
javajeep said:
I want to start this post by saying that I searched -- for a long time. I want to know how to get the codes off my heep from home.

1. I have done this before. At least I think I did. Am I getting mad cow? I am certain I did this last year.

2. I have read a lot of threads on here saying it can not be done for a 1997. I am sure I did this before.

3. I learned how to do it from a post on this website -- I have searched a long time -- I can not find it.

OK -- now to my CEL problem:

I went to autozone. Yes -- they do it for free, but I want to be able to do it from home. I have an O2 sensor code. It is the only code. Because it is the only code, it was suggested that the sensor was probably bad. I bought one for $65.

I have two concerns. The old one looks like it has a lot of rust/crud on it. Should I be concerned about problems with getting it out?

My second concern is that after reading this thread:

http://www.naxja.org/forum/showthread.php?t=913555&highlight=check+codes+procedure

I am wondering if the problem is the gas cap. What kind of code is caused by faulty gas cap? Is there actually a specific code for the gas cap, or is it diagnosed indirectly by an emissions code?

Thanks for all of your help.
Click to expand...


My '99 throws the O2 code every year when it gets cold out, expecting it anytime now. It has done this for the past 4 years. I haven't replaced the o2 senser and it still runs fine. The code goes away after a day or two. The longest it has stayed on was a week.
 
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