1. #1
    trat73's Avatar
    trat73 is offline Junior Member
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    P0128 Code Problem

    Hello all.
    Having an issue on 2006 2.4L TJ. The P0128 code keeps coming up. I've done the following:
    Replaced thermostat with Stant 195 SuperStat
    Replaced the Coolant Temperature Sensor (also Stant)
    Flushed and Burped the coolant.
    Still getting the P0128 code. Any ideas?

  2. #2
    JPNinPA's Avatar
    JPNinPA is offline Senior Member
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    P0128 Code Problem

    P0128 code happens when the PCM doesn't see the temp hit 65 deg within a certain time from start.

    Where do you live? Winter here can cause this or a Thermo stuck open or opens early.


    First clear the code by disconnecting the battery and turning the key to on then off and reconnect battery. See if the code returns.
    When you changed the Thermo was there anything wrong with the old.?


    Did you put Teflon tape or anything on the new temp sensor?

    Here was my issue....Thermo early failure.
    https://www.jeepz.com/forum/cj-yj-tj...o-failure.html (P0128 Thermo failure)


    Regards,
    JPNinPA

    Sent using TapTalk
    Last edited by JPNinPA; 07-11-2019 at 05:05 PM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

  3. #3
    trat73's Avatar
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    Re: P0128 Code Problem

    Hello. Thank you for getting back to me so fast. I had recently purchased the Jeep when the code first appeared. I have a reader and cleared it after I replaced the thermostat with the Stant Superstat 195 and flushed the coolant. It came on again and I changed the sensor (it had a coating on the threads so I didnít Teflon). It is now on a third time so I ordered the standard Stant thermo and will try that. Did your prob go away after installing the Napa thermostat?
    Thanks again!!!


    Sent from my iPhone using Jeepz.com mobile app

  4. #4
    JPNinPA's Avatar
    JPNinPA is offline Senior Member
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    P0128 Code Problem

    Yes
    Some of the thermos like super stat are built to fail open. And that is just what they do. If you followed my link you could see the few month old thermo that failed. My guess it failed within 2 weeks. Cause gas milage came and went.
    Sad but true there are aftermarket parts that fail out of the box or within a month.
    If you need any sensors, buy OEM.

    PS Stant makes the OEM part #14209 The bleed valve should be positioned at the top when installed.


    Sent from my iPhone using Jeepz.com mobile app
    Last edited by JPNinPA; 07-12-2019 at 07:51 PM.
    "Never look down on anybody unless you're helping him up" - Jesse Jackson

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