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Thread: '03 GTP "Service Engine Soon" warning light...

  1. #1
    Join Date
    Jun 2009
    Location
    N. Attleboro, MA
    Posts
    12

    Question '03 GTP "Service Engine Soon" warning light...



    Ok...I've basically rebuilt my entire cooling system for my GTP.

    I'm all happy going to work this morning she's running real fine and all of a sudden the "Service Engin Soon" light pops on.

    I just did an oil change and as I stated above my cooling system is tight and running better than when I bought the car off the snot-nosed kid who abused her.

    I've gone through the manual and can't really seem to find what exactly I should do about this. Like I said she running great, all my pressures and temps are dead-on, no hesitation or timing issues and ampers are right on the money too.

    My millage is 67567. Is this a "general" service warning that kicks on at a certin millage marker in the computer system?

    Any advice you can give would be gladly accepted.
    "One foot on the break and one on the gas...."

  2. #2
    Join Date
    Jan 2007
    Posts
    4,850

    Default

    Hi Session9,

    See Chapter 6, Section 2 of your Haynes manual and check to see if there are any trouble codes stored in the computer, then go from there.

  3. #3
    Join Date
    Jun 2009
    Location
    N. Attleboro, MA
    Posts
    12

    Default

    Yeah, I'm going to do that as soon as I get home. I also just ordered the OBD-II book from you all (as well as a coffee mug). If this doesn't work I'm gonna go to onw of the local shops and have them diagnose the issue on their system. I'll try mine 1st but I think it may be too basic.

    Thanks for the info.
    "One foot on the break and one on the gas...."

  4. #4
    Join Date
    Jun 2009
    Location
    N. Attleboro, MA
    Posts
    12

    Exclamation Engine Coolant Temperature Sensor location - '03 3800 GTP

    Ok, the code I got was P0128, Coolant Sensor.

    Could you please clarify the location of the sensor for my 3.8 model. The book says two things: (1) It's usually near or around the thermostat area and (2) on some models it's on the right side of the block, below the #1 cylinder (Above or behind the power steering pump on the fire wall side? ).

    Anyhow, I picked up a new sensor and just need the location of the ECT sensor so I can replace it.

    Thanks in advance for your help and continued advice!
    "One foot on the break and one on the gas...."

  5. #5
    Join Date
    Jun 2009
    Location
    N. Attleboro, MA
    Posts
    12

    Default

    Woo-hoo!

    Easy fix, it was the Engine Coolant Sensor and it's in the same place as the GT 3800. A nice "easy" place to get into...below the thermostat in between the block and the exhaust manifold! Fun-fun, gotta love those Pontiac engineers! LOL
    "One foot on the break and one on the gas...."

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