Chrisking015

Hey guys, I have a 1996 XJ. I recently had a problem with the jeep over heating. So I flushed the coolant system and replaced the thermostat. While checking everything to make sure everything was ok. I noticed that my fan wasn't coming on. After a few mins jeep started running rough. I looked it up and found out that the temperature sensor may be bad causing it to run rough. So I replaced that too. After that it ran fine for a day or two. Then I got the same code (P0118). So I replaced just the plug connector. It ran fine for a day and then it done it again. So I was wondering if there is a wiring harness I could buy to replace the one on the jeep now. I thank it would be easier to just replace the whole harness than trying to find a short in the wires.

LadyKenai

the coolant temperature sensor is just for indication it wont influence how the engine runs, the sensor triggers the auxilary fan to kick in when the coolant temperature reaches around 230F. you can meassure the temperature with a infrared thermometer gun by aiming it at the thermostat housing. There are many threads on this forum that will disguss this issue.. searching the forum will give you lots of pointers what to check for.

marc

jordan96xj

In the service manual, the engine coolant temperature sensor is listed as an important source of data for nearly all phases of the 4.0 motor operation on a 96. Especially on startups where it uses it to know which fuel strategy to use for initial start and idle setting. It is also used during fuel trim adjustment calculations which can most definitely influence how the engine runs. Ironically, the one thing it is not directly responsible for is controlling the gauge position in the cabin (on a late build 96 at least, on an early 96 build it was used directly).

But replacing an entire harness because there -might- be a short on the engine coolant temperature sensor is a little severe. I don't think you'll find an aftermarket harness for a 96. Pulling out of a junkyard is sometimes what folks do, but you are likely pulling a 200k+ mile harness that may be not much better than what you have.

What a person really needs is an accurate 96 wiring diagram. Which itself is a little tricky to find. But that way you can test the ends of the wires, knowing what they should be doing, and then deciding if a portion of the harness needs to be addressed.

Shorting is rare. Shorting inside a good portion of the harness is more rare. Shorting where the harness has rubbed on something is less rare. Broken wires, rubbing/shorting wires outside the harness, bad connectors, failed components, and poorly maintained ground connects are much more common.

Chrisking015

Ok thanks guys, I will check all my grounds and if I can't find a bad ground then I will just start looking for a short in the harness.



Chris

EZEARL

You may want to pull the t-stat housing and see if corrosion is causing the problem. I had the IAC and CTS code yrs back. Just polishing the end of the CTS solved it's problem. Guessing it hindered the sensor from sending the correct signal.