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How do i resolve a P0118

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Old May 25, 2005 | 06:28 PM
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Default How do i resolve a P0118

In short, my temp gauge drops to 'null' and the car runs really rough. I first expierenced the issue just over a month ago. a week later i bought a new ect sensor from the dealership.

The last few days (since it has been 100*+ out) the car has being doing this more frequently. I hooked HPTuners up to the car and pulled the DTCs this is the only one that came up.

How do i resolve the issue? Ive seen a few threads while searching for this code that had a full diagnoses in them. Where do these come from? The had my code listed along with a few others under DTC but nothing for the specific one.

any help is appreciated.



the MAF code is because i am currently running in SD mode.
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Old May 25, 2005 | 08:51 PM
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Sounds to me like your ECT signal wire has a short to voltage in it. That would set this perticular code and make your temp read extremly low. If you have already replaced the sensor then that can't be the problem. Use a volt meter and check the volts on all 3 wires at the ECT harness. I don't know the wire colors off hand, but one should have ground (no volts), one should have 5 volts (reference) and the third is your signal wire. It should not have anything (voltage or ground). If you have 2 wires with 5 volts or 1 wire with 12 volts then your signal wire is the problem. I will look up the wire colors tomorrow at work.
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Old May 25, 2005 | 11:55 PM
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^^^ ditto

Check the wire for the ECT sensor... make sure it's not corroded or anything... it is on the drivers side head I believe
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Old May 26, 2005 | 12:51 AM
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i just got done taking a look since the car had all evening to cool off. The wiring on the connector looks fine although it was a bit dirty. I went ahead and disconnected it and sprayed lectra electical cleaner on it. after it dried i connected it back up.

when two say to check the ECT harness, do you mean @ the VCM because i only have two wires coming off of the ect sensor connector - a black and a yellow.

the biggest thing to me is that nothing major has been done to the car since before last summer. It ran fine all that time, but this summer things are acting different.

The one minor difference is i am currently only running 1 tranny cooler (tranny -> 24,000 ->tranny) instead of having them in series (tranny - >24,000GVW -> 28000GVW->tranny) my dad is trying to tell me that the heat from the converter could be causing this. He says that the fluid in upfront, in the cooler, is too hot from the tranny causing the coolant in the radiator to become even more heated. do you believe this could be the case?
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Old May 26, 2005 | 06:45 AM
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You have 2 different coolant sensors. The one with 2 wires feeds your gauge. There is another one that has 3 wires and that is the one that feeds the PCM. Like Horist said, it is on the driver side head in the front, right above the #1 spark plug. I will check the wire colors and get back to you tonight.
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Old May 27, 2005 | 05:34 PM
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Well I stand corrected. After looking at the wiring diagram, the sensor with black and yellow wires is the right one. The black is a sensor ground sent from the pcm, and the yellow is the signal return line. That is the one you should be looking at. Sorry for the confusion.
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