Hey everyone! Thought I'd throw my codes out there and see if anyone has any ideas. I bought my daughter a 01 last year for her first car, it's been really good but it's had a P0303 code that keeps popping up. Hasn't really been an issue, it starts and drives normal. But a few days ago, it started acting up again and I went and got it and brought it home from her work. It ran fine for me but when I got home and shut it off and started it back up after about 5-10 minutes it was running really rough like she had said it was doing. Also it's been having a P1281 code for engine is cold too long, the temp sensor wasn't working when we first bought it and I changed it out and it's been intermittent ever since. Another weird thing that happened now also is we had an alarm installed and now the alarm won't control the door locks. I'm gonna do some more digging when the weather gets better but I thought I'd throw this out there and see if anyone had any ideas. Thanks!

Chris

 

First if you haven't all ready Google 0331 head in XJ Jeep and read up on it.
Now don't get all worried yet but thinking you should be aware of the problems with this head.
Now from reading stuff on the internet it appears that P0303 and P0304 misfires might indicate a head problem.
But in my '00, which is basically the same as your '01, I had a P0304 once.
Literally turned out to be a bad spark plug. So you might want to try swapping that out.
As far as the temp sensor goes what brand did you use?
The unwritten rule is try to always use Mopar sensors.
So I am wondering if you used an aftermarket one if it is just defective.
Also the intermittent problem makes me wonder about the wiring to it which you might want to check.
Also Google grounds in an XJ Jeep.
Whenever there is electrical problems it is always good check them first.
Now this is not a just look at them thing. This is a disconnect them, clean them up, and put it all back together thing.
Personally if this were me I would yank out the aftermarket alarm, door lock, and guessing remote start set up.
Cause I would have to wonder if it was done right and figure take that out of the equation and see what happens.
'00's and '01's have what we call the wasted spark thing going on.
There are 3 coils in that coil bar and they spark 2 plugs each at the same time.
My thinking is if it were a problem with the coil bar you would have 2 misfire codes.
A compression test might be worth doing too.