CEL Code

Gday gents,

first time poster (and Jeep owner!) - hopefully, ive posted this in the right section. I've come asking for your expertise please - i can't make heads or tails from the CEL code im getting from my Jeep.

I've got a 1995 XJ Cherokee, 4WD, 4.0L Auto (no turbo). Its got a 4.5" lift with 33" muddies. Previous owner has not done the diff gears, so the diffs are stock (D30 front and D35 back).

I was repeatedly getting the CEL when i took the family camping over Easter. We went up into the mountains with a Jeep full of camp gear, and because of the stock diff gears, she struggled up the hills. 30 mins into the trip (on the hills) the CEL went off. It went away as soon as i turned ignition off and started it again. Engine seemed fine, all gauges reading nominal. This happened a few times, but it happened less frequently if i let the vehicle cool down for 30mins. Oddly enough, the CEL did not turn on again once on the way home (mostly down hill, 4hr drive).

I checked the code, but cant quite make out the number because of the odd sequence of flashes and pauses. Was hoping you guys could confirm for me?

I think im getting a Code 36 (Air Switch Solenoid). Which i cant seem to find any info in the 95fsm for!

Here's a youtube video of the CEL flashing (using the "ignition key turn to on 3 times" trick). Would really appreciate some assistance.

http://www.youtube.com/watch?v=K5tOIqSdUlI&feature=youtu.be

Kind regards,

Skiman

Skiman,

From your youtube video I saw codes 12, 51, and 55.
12- battery has been disconnected in the past 50 key cycles
51- air/fuel ratio (O2 sensor)
55-End codes

I would say that your O2 sensor is failing and to replace it. Part of the reason it may have just showed up is that you are running the larger tires on stock gears, full of gear, up hills. This really give the engine a work out. Its like trying to ride a 10 speed bike up hill in 10th gear from a stand still. You can do it, youll just find new pains in your body you didnt know you had!

Sure is weird seeing everything backwards on the dash!

Here is a good link for the blinking light codes;
http://offroad-review.com/new/index.php?page=161

I hope this helps!

Aaron

Hey Aaron.. wow man, thanks heaps for your help! No wonder a young friend of mine speaks so highly of this forum.

I didn't realise there could be more than 1 error code in there!

Code 12 makes sense because i had an issue with the battery terminal recently.
Code 51 also makes sense.. the fuel economy has been ordinary since i've owned it (couple of months) and the sensor looks pretty old and rusty. Have also noticed a rich smell from the exhaust after getting out of the car.

Will change the sensor straight up! Its an easy fix after all. Is it worth taking her to the Jeep dealer to have them reset the codes? I guess this isn't possible without the correct scanner tool? Might be a good investment to buy one of those Actron devices i saw in your link

Again, many thanks for your help mate. Much appreciated.

Not a problem sir!

As long as the light is not on all the time, I would not worry about "resetting" the computer. However, I normally reset the computer when I put on new sensors so the ECU can relearn them. All you need to do is pull the battery for 10 min or so and the memory in the ECU will clear. When you do this, the computer will retrain itself for a little bit so it may run a little funny at first until it figures it all out again.

Aaron

skiman said:

Is it worth taking her to the Jeep dealer to have them reset the codes? I guess this isn't possible without the correct scanner tool? Might be a good investment to buy one of those Actron devices i saw in your link

Click to expand...

Not sure about the parts stores in Australia, but here in the states most parts stores will read codes for free.

redneck said:

Not a problem sir!

As long as the light is not on all the time, I would not worry about "resetting" the computer. However, I normally reset the computer when I put on new sensors so the ECU can relearn them. All you need to do is pull the battery for 10 min or so and the memory in the ECU will clear. When you do this, the computer will retrain itself for a little bit so it may run a little funny at first until it figures it all out again.

Aaron

Click to expand...

Not that 10 minutes is along time, but if you ever need to turn off a CEL or reset the computer, you can put both terminal wires and touch them together for about 15 seconds and then re attach.