Hello! I have a 1999 jeep Cherokee classic 4.0 automatic. It sat for a few year and when I bought it from my brother it needed many parts replaced. After replacing the exhaust system(cat back), complete tune up, all new brakes, hubs and u joints, new o2 sensors, I have fixed most problem and codes from the computer but one still remains. It code p0135, I've checked the wiring and the fuses, reset the light but it still comes on and the jeep still hesitates when cold. Any ideas would be greatly appreciated thanks

do this http://www.jeepforum.com/forum/f9/cl...mmies-1114849/

hope it well fix it ,if not its a great thing to do with a jeep sat for few year , at least it may fix hesitates when cold

Thank you for replyin first off, much appreciated. I have already done this procedure and yes it did help dramaticly while driving when the engine was warm. I believe my problem with the hesitation is due to the o2 sensor heater malfuction because its only when it is cold, once the o2 sensor is up to temp it goes away and it drives fine. I haven't checked voltage yet at the sensor but will do so tomorrow. This seems to be a common problem only most of the common fixes aren't my solution.

I know you said you checked fuses, but check the O2S heater fuse in the PDC, shown in this pic. Disregard the ASD Contactors fuse.

I did check that one before and all the others just in case but just to double check since you mentioned it I checked it again and it isn't blown

this video should help you to check if there is a problem with your o2 you well need a good live reader

Thank you I will borrow my friends reader and take a look at the live readings tomorrow hopefully it will show something that will help

So I just realized that the reader actually had two codes stored, p0135 and p0132--which is high voltage and it was on the same sensor bank 1 sensor 1. I was doin some work yesterday and had the battery disconnected so the codes were erased, so I have to wait for it to come back up to do a live read on it. Hopefully soon

Saved me from doing all kinds of random stuff to find the issue ! Fuse was blown, thank you !!!

If that pic of the PDC was helpful, tuck this one way for future use (also applicable to '97 in most cases).





PS: A fuse usually blows for a reason. Examine the upstream O2S wiring as it passes over the intake manifold for chafing. Examine the downstream (CAT) O2S wiring for defects.
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PS2: You may want to enter your Jeep data in your signature as I did. It helps in future posts.

every pix i see here i right click and save as,,they go into a 'jeep pix'folder on desktop.
lots of other stuff in there too..