CEL on first freeze

[Xenon84]

Hi all, just joined the forums and its already proved handy. Thanks Hyde.
I figured I would check if anyone else has had this problem. My Fiance' and I have had our 03 m/t for two years now and at the start of winter (the first good freeze) the jeep has always thrown a CEL. It only lasts between 30min and a day and only appears if it warms backup and then freezes again otherwise not till the next Winter.
I pulled the code but forgot to right it down. Came out as a Stuck Therma Sensor, I looked through everything I could and couldn't find anything wrong. Not too concerned bout it since it always has gone away, and haven't noticed any difference in performance, just wondering if anyone else has experienced this? Cheers! arty52:
I did search and found a couple similar, but didn't recognize the code's posted.

 

[tjkj2002]

If the code was P0128 you need to change the t-stat which should be changed when the coolant is flushed which you are well overdue for.

 

[LibertyTC]

x2 as above.
Jeep Requires dealer HOAT coolant. It should be flushed out every 5 years but many do it more often than that. The dealer has the coolant & correct machine for doing a proper flush and I would let them replace the Thermostat while there. Just had mine flushed and it is now good to something like -58 or something serious.
If you are a DIY you can use Zerex G-05 and do the thermostat, but I still recommend a dealer service for flushing. I think they only charged me $130.

 

[Xenon84]

Thanks! Good to know, I figured when we bought the jeep from a dealership they had done this maintenance since they had replaced the brakes and rotors. I will look into it!