ChrisJeep

I have a 1994 Jeep Cherokee 4.0L (150,000 miles) -- and my engine light comes on at start-up then goes off after a few minutes. Power steering fluid was low but can that even cause an engine light?

I went to Auto zone but they couldn't find where to hook the scanner up on my 1994. Embarassed to say, but I have my jeep key stuck in the steering column - have for years now . So I can't do the turn on/off method of getting a code myself.

On the bright side, I do have a USB scanner OBD cable with both the old (2 wire) and new type of plugs -- but I have no software for it. I used it on my VW -- I have a nice new little netbook if that helps so I can use the cable with the right software - if I can find where to hook it up on my cherokee.

Just also want to say that the Engine seems to run a tiny bit rougher and maybe louder than it has in the recent past - but my gas/MPG seems about the same 16MPG.

I had changed the plugs and wires about a year back...

Any ideas?

96Cherokee113

Only the OBD II cars which are 96 and newer have the plug for a code scanner. You'll have to pull the codes with the on/off trick. Having the key in shouldn't matter, since you never actually have to take the key out. There might be the "Diagnostic" port under the hood which has something to do with pulling check engine codes.

ChrisJeep

That was quick -- thanks I'll try that -- as far as the under the hood plug for codes what type is that?

96Cherokee113

To be honest, I have no idea. I always see them under the hood of cars, but was never sure exactly what you needed to make use of them. It's seems to always be a square port with a rubber "boot" over it labeled "Diagnostic." I'm assuming it's used to pull check engine codes. It may be something they use at the dealer, but I'm not too sure.

greengoblin

you have the obd1 computer system and the plug should be under the hood somewhere thats why they couldnt find the plug

ChrisJeep

I got a key code that was 34155

all I could find online was this partial code

==================

34*

An open or shorted condition detected in the

speed control vacuum or vent solenoid

circuits.

or

Speed control switch input below the minimum

acceptable voltage.

or

Speed control switch input above the maximum

acceptable voltage.
===============
I got it from here:


http://74.125.113.132/search?q=cache...&ct=clnk&gl=us

littleredXJ

It's 16 years old... If it is running fine and gas mileage hasn't changed I would just chalk it up to personality. I have a 90 and if it had a check engine light i'm sure it would come on and tease me too.

ehudpower

Found this in my Chilton Book.
Code 34- speed control servo solenoids or MUX speed control circuit HIGH/LOW-open or short detected in the vacuum or vent solenoid circuits or speed control switch input above or below allowable voltage!!

ChrisJeep

Thanks for the Chilton code info!!

From my Cherokee blinking light I got a key code of 34155 - but all I could find online was this info for the partial code of 34- (are the last 3 digits just for show? lol )

Now for the Million Dollar question... any idea what this means in English? Should I get replacement vacuum hoses? I changed some of them a few years back - got them at an ACDelco store -- but I will try the stealership this time around - the ones I used are a bit brittle now and didn't wear very well -- but I really am not sure that these are my problem!!!

Could it still be an o2 sensor? I don't speak repair manual too well!

==================
34* == An open or shorted condition detected in the speed control vacuum or vent solenoid

circuits. (or)
Speed control switch input below the minimum

acceptable voltage. (or)
Speed control switch input above the maximum

acceptable voltage.

===========================
also:

Code 34-Speed control servo solenoids or MUX speed control circuit HIGH/LOW-open or short detected in the vacuum or vent solenoid circuits or speed control switch input above or below allowable voltage.

===========================

ChrisJeep

I'm going to change the vacuum hoses right now .... but I failled to mention something that might now be important -- right when this first happened my voltage meter on the dash dropped lower than I had ever seen it go, right above (or into) the red area -- but since then it now stays straight up.

My code reading says..."speed control switch input above or below allowable voltage."

By the way, I don't have cruise control.

I will check the voltage with a hand held meter while I change the vacuum hoses!

ehudpower

either you messed up and got the wrong code or something. My chilton book only has code 34 for your year for your jeep. Unless maybe the other numbers tell you where its located i have no clue at all. Also about you loseing power hope its not the same problem i am haveing with my 1989 cherokee. It ended up being the crankshaft postion sensor!!

ChrisJeep

Whoops. I think I misread the code!

It is rainging here so I looked at video of the flashing light that I had taken with my blackberry.

I might post the video of the light -- it clearly blinks 3 times - then 4 times -(then a little too quickly) 1 time - then 5 times - then 5 times

3-4-1-5-5

Though the 4 and the 1 were closer together then the others so maybe it was really is
3-5-5-5

I looked this up online just now:
"Code 35 Radiator fan relay open or shorted"

...and I did replace my Radiator Fan last year...

I had also noticed that this electric fan was coming on and off more often and rather erratic and on a hot day recently it got a little hot while it was idling!

-------------------
The 55 seems to just be an end code:

Here is more from the web about codes:
http://www.allpar.com/fix/codes/index.html

Looking at the Power Limited light, count the flashes. These will come in sets of two flashes. For example if you count one flash then after a pause two more that’s a code 12. This will be followed by five flashes and a pause then five more. This is a code 55 or ‘end of file’. Codes will always end in a code 55 and there will be no more flashes. This is the computer’s way of telling you that it’s all done. If the only code you receive is a 55 then you ‘have no fault codes’ and the computer has nothing to report.

Anyone ever change a fan relay switch or just a fan relay? here are two links

http://wiki.answers.com/Q/How_do_you...ive_6_cylinder

http://www.ehow.com/how_5541658_test...-cherokee.html

ChrisJeep

I tried swapping the relay but that didn't solve the problem -- but while I was plaing with it the battery gage on the dash suddenly drpped down again to just below the red zone ( around 12 volts) as it turns out I had a metter and it is now fluxating between 11.3 and 12 volts. The battery was replaced on 10/2009 -- I'll get it tested but I bet it is my alternator/regulator -- If it isn't the battery then it should cost me about $250 to have someone replace that.... Any advice? I think this is the only alternator the jeep ever had -- I also think that it might be making a little noise...

Maybe this will somehow fix the check engine light too....

ChrisJeep

Thanks for all the help! Everything seems good since I put in a new Alternator. I charged my AC unit too - so the compressor stayed on all the time. So far so good! I do have a slight leak in my power steering now -- not sure why -- I changed the high pressure line last year but otherwise things are perfect.

For a 1995 former MTA jeep!