2003 cts engine code po118
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Cadillac CTS First Generation Forum - 2003 - 2007 Discussion, 2003 cts engine code po118 in Cadillac CTS Coupe, Sport Sedan and Sport Wagon Forums; i have a 2003 cts with a trouble code po118...engine coolant temp circuit high input...the engine coolant temp sensor was ...
  1. #1
    coldgin is offline Cadillac Owners Member
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    2003 cts engine code po118

    i have a 2003 cts with a trouble code po118...engine coolant temp circuit high input...the engine coolant temp sensor was changed and still tripped this code...also we changed the electrical connector and the wires on the connector were both white...the old connector had a yellow and brown wire...could the wires be crossed?also is the thermostat setting this code?and i assume the thermostat is probably hard to get to....any info is appreciated...also the dash screen says "engine hot a/c off"...that is why i am leaning to a thermostat...thanks again for any help

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  3. #2
    txbest1980's Avatar
    txbest1980 is offline Cadillac Owners Master
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    Re: 2003 cts engine code po118

    the thermostat is a biatch to get to for sure, but it can be done. but i would try swapping those wires around and seeing if that fixes your problems before i would move onto something else

  4. #3
    ghettomike's Avatar
    ghettomike is offline Cadillac Owners Master
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    Re: 2003 cts engine code po118

    I had my thermostat done and it fixed it. Took a few hrs because you have to take the intake manifold off and then start digging.
    I've heard some guys paid $1000 for the t-stat...I paid under 100 ...good hookup

  5. #4
    WickedGoat's Avatar
    WickedGoat is offline Cadillac Owners Fanatic
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    Re: 2003 cts engine code po118

    The thermostat could be the culprit.... I was getting P0128 and I replaced the thermostat since I was halfway there. It was stuck open when I pulled it out. One other thing you may want to check is the valve by the radiator. If you are staring at the engine from the front of the car, it is to your left at the top of the rad. There is a small vacuum hose that should be attached to it that runs to another plug just below it. This line dry rots over time and it can fall apart. This valve has something to do with coolant flow so make sure that isn't the problem. The thermostat is not a quick 30 minute job on the 3.2, so make sure all else is OK before going there.

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    coldgin is offline Cadillac Owners Member
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    Re: 2003 cts engine code po118

    thanks guys for the info...i am thinking it is the inevitable that it is the thermostat....i will check the vacuum hose on the radiator also...i definitely didnt want to hear the thermostat is under the manifold...

  7. #6
    Kingoftypos is online now Cadillac Owners Master
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    Re: 2003 cts engine code po118

    Can you go down to your local parts store and have them scan your car. Most readers should be able to provide a "freeze frame" of what is going on. Which will give a temp on the coolant. Since the 03's didn't have a temp gauge. :-/
    However, speaking of that you can always buy an 04 to 07 cluster and install it. It's basically plug and play and the temp gauge will work just fine. The only down fall is that you would have to find a cluster that is pretty close to your mileage. Or have it sent out and pay for them to match your mileage.

    KOT

  8. #7
    coldgin is offline Cadillac Owners Member
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    Re: 2003 cts engine code po118

    it is actually my nephews car and i took it to advance auto parts and got it scanned...there was a green idiot light on the dash come on while i was driving stopped at a redlight...i assumed it is the temp light...going to change the thermostat and see if that takes care of it

  9. #8
    chude is offline Cadillac Owners Member
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    Re: 2003 cts engine code po118

    how did it go? cos i am having same problem right now

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