Two questions

[SLiM]

First question is my check engine light has been coming on but not all the time, any ideas on what that could be? I was thinking O2 sensor?? And the second question what is the biggest tire I could get on my stock rims and with out a lift kit on it. I want something with an aggresive tread and can I get something that would stick out a little more? Anyway any advice would be great.

 

[SteelHeadz]

I'm not sure if the aftermarket scantools are able to read stored DTC's on an ECU. The DRB3 from Chysler can and will also give you failure counts vs. good trips. If the SES lamp is not staying on long enough for a generic scantool, the dealership scantool would be an option but pricey.

 

[SLiM]

I think I figured out why the check engine light is on, I think ny Alternator went, my voltage gauge is almost in the red right on the 9 and I just put a new battery in it two weeks ago cause that went. So I think thats what it is, anybody think I am in the ball park on this? Thanks in advance everyone.

 

[MudderChuck]

My voltage tests 14+ volts at the battery poles with the motor running and my in dash volt meter reads normally about the same as yours. My assumption is my in dash volt meter is a liar.
Intermittent low voltage can likely cause the CEL to light up intermittently. I'd pay attention to when it happens. Low voltage is more likely at lower RPM's, O2 sensor malfs are more likely (in my experience) around 2000 RPM (and mildly accelerating) in the beginning stages, when they start to fail..
You might want to try the key on and off method and count the CEL light blinks, using a code list and see if you have any stored codes. This method may put you on the right track.

 

[SLiM]

My voltage tests 14+ volts at the battery poles with the motor running and my in dash volt meter reads normally about the same as yours. My assumption is my in dash volt meter is a liar.
Intermittent low voltage can likely cause the CEL to light up intermittently. I'd pay attention to when it happens. Low voltage is more likely at lower RPM's, O2 sensor malfs are more likely (in my experience) around 2000 RPM (and mildly accelerating) in the beginning stages, when they start to fail..
You might want to try the key on and off method and count the CEL light blinks, using a code list and see if you have any stored codes. This method may put you on the right track, but is far from diffinitve.

How to I check the codes? Is there a list of them?

 

[MudderChuck]

Here is one list, it may not be the best. The code list has changed some from year to year, some codes have been added or a newer list my show possible codes your PCM doesn't record.
How to get the codes:

I'm pretty sure your 92 has the CEL code function.

I sometimes have to try a few times to get this to work, the key on, key off, sequence seems to take a certain rhythm.

 

[FloridaCherokee1988]

If I was you i'd take it to the nearest parts store so they can put it on the diagnostic machine real quick, they should be able to tell you exactely what the problem is by which code it puts out. And the tires, i'd say maybe a good set of 225-245/75/15's, you might get away with some 30x10.5's though.

 

[SLiM]

Here is one list, it may not be the best. The code list has changed some from year to year, some codes have been added or a newer list my show possible codes your PCM doesn't record.
How to get the codes:

I'm pretty sure your 92 has the CEL code function.

I sometimes have to try a few times to get this to work, the key on, key off, sequence seems to take a certain rhythm.

i got 34 and 14, does that tell you anything

 

[SLiM]

Codes????

I got two codes for my 92 Jeep Cherokee 4.0 I got 34 and 14 anybody know what has to be fixed?

 

[MudderChuck]

i got 34 and 14, does that tell you anything

14 is the MAP sensor, but my list (for 95) says if this code is thrown the CEL will remain lighted and not be intermittent.
34 is (I'm guessing here) in the speed control circuit, my guess is cruise control and my list says this can be an intermittent CEL light.
I'd recheck the blinks, I almost always start out with a 12 code (battery has been disconnected in the last 50 key on key off cycles) and ends with a code 55 (end of test). My codes also repeat (same code twice) for each code, usually, but has been a bit quirky on occasion.

 

[SLiM]

14 is the MAP sensor, but my list says if this code is thrown the CEL will remain lighted and not be intermittent.
34 is (I'm guessing here) in the speed control circuit, my guess is cruise control and my list says this can be an intermittent CEL light.
I'd recheck the blinks, I almost always start out with a 12 code (battery has been disconnected in the last 50 key on key off cycles) and ends with a code 55 (end of test). My codes also repeat twice for each code, usually, but has been a bit quirky on occasion.

My check engine light has been staying on now for two days

 

[MudderChuck]

My check engine light has been staying on now for two days

In my experience if the MAP starts to fail, the motor idles poorly and way rich.
I'm not real familiar with your year XJ, I've got an 88 and a 96.
First thing I'd do is unhook the battery for awhile and then take it for a drive. I avoid extended idle when the computer is rebooting (seems to work better for me), also avoid jiggling the battery terminal when reconnecting, make sure the key is off.
I'd also check the grounds at the dipstick holder, these grounds are a known trouble spot and ground most of the sensors, PCM, TCU and the battery.
In my experience when the MAP acts up, it is usually the vacuum to the MAP, a dirty or poorly seated connector or another sensor is partially shorted sucking down the 5 volt supply circuit to the MAP.

 

[SteelHeadz]

Re: Codes????

DTC 14- Map sensor circuit too low or too high. DTC 34-Speed control. (Always low, switch is always high, cotrol circuits open or shorted on the vacuum vent solenoid circuit).

 

[SLiM]

In my experience if the MAP starts to fail, the motor idles poorly and way rich.
I'm not real familiar with your year XJ, I've got an 88 and a 96.
First thing I'd do is unhook the battery for awhile and then take it for a drive. I avoid extended idle when the computer is rebooting (seems to work better for me), also avoid jiggling the battery terminal when reconnecting, make sure the key is off.
I'd also check the grounds at the dipstick holder, these grounds are a known trouble spot and ground most of the sensors, PCM, TCU and the battery.
In my experience when the MAP acts up, it is usually the vacuum to the MAP, a dirty or poorly seated connector or another sensor is partially shorted sucking down the 5 volt supply circuit to the MAP.

Thanks alot bro, I will check it out in the morning and see what happens
And where is the MAP sensor located?

 

[SLiM]

Re: Codes????

DTC 14- Map sensor circuit too low or too high. DTC 34-Speed control. (Always low, switch is always high, cotrol circuits open or shorted on the vacuum vent solenoid circuit).

How hard is it to fix it, I am no mechanic Im a carpentor...lol

 

[SteelHeadz]

Re: Codes????

It could be as simple as replacing the parts in question or as difficult as tracing the wiring for faults. The term "Circuit too low" means it could be a short to ground or short to voltage. The term"Circuit too high" means an open short or voltage too high. Since the 2 components involved are controled by a 5volt pull up driver circuit from the PCM, it's a matter of checking and verifying the connector and wiring for loose or possibly chaffed or even severed from the harness. Anything after that, if nothing else jumps out, I'd call the wiring good and test the components in question and replace them as nescessary.

 

[SLiM]

Re: Codes????

It could be as simple as replacing the parts in question or as difficult as tracing the wiring for faults. The term "Circuit too low" means it could be a short to ground or short to voltage. The term"Circuit too high" means an open short or voltage too high. Since the 2 components involved are controled by a 5volt pull up driver circuit from the PCM, it's a matter of checking and verifying the connector and wiring for loose or possibly chaffed or even severed from the harness. Anything after that, if nothing else jumps out, I'd call the wiring good and test the components in question and replace them as nescessary.

That would be easy if I knew where to look and what I was looking for, I should get the haynes manual for it, that would help with alot of things. If I where to bring it to the shop that has been working on my jeep from the day the last owner bought it which was in 92, They are pretty reasonable with there pricing. do you know about how much something like this would cost to have fixed?? I have about $600 bucks in my Jeep acount, wanted to use it for a new exaust system but if I have to I will use it to fix it. Thanks for all the help everyone, I would be lost with out you guys

 

[SLiM]

Well everyone, I fixed the electrical problem, all I did was disconect the battery for awhile, then put them back on, which someone told me reboots the computer, well it worked I took it for a drive and about halfway home my battery gauge went right back to 14!!! The check engine light is still on I dont know why, but it runs like a champ. Thanks again everyone!!!

 

[FloridaCherokee1988]

Well atleast shes runnin good lol if you fixed it and it's still puttin out the same code then i'm stumped on this one too.

 

[SLiM]

Well when I went out this morning to take a drive, the check engine light was out, then it came on the meter ws at 9 again, after it warmed up and I drove it for about two minutes, the meter jump up to a a hair over 14??? And the light is still on. I also noticed that the speedometer is slugish, it doesnt start to move until I am ready to shift into second gear, I guess its gonna have to go into the shop, because I am completely out of ideas on what it is and how to fix it, plus with the wind chill its -7 out, and I live in an apartment complex and have no garage to work on it in. I will let eerybody know what my mechanic says. Thanks everyone!