Coolant Temp Gage pegs cold

[Trebor]

Hi, New to forum and to Chevrolet.
I recently purchased a 2007 Chevy Equinox LT with the 3.4 liter engine. Twice, while running the heater, I noticed that the temperature gauge was pegged cold, that the Driver Information Center was displaying "Engine Hot A/C OFF" and that both cooling fans were running. I pulled over and checked: The engine was not hot, could squeeze radiator hoses and even open coolant reservoir. Later, after engine off for over an hour, started car (heater off) and same thing. Then, after driving for a several minutes, I happened to catch the temp gauge suddenly change from pegged cold to about half way. At that point everything returned to normal.
I gather the temp sensor is an input to the computer and that the computer drives the gauge. Makes sense that if the temp input is lost that the computer would take these actions. My question: is there some connection between the heater blend door and the temp sensor that would cause the temp sensor signal to cut out? Can't seem to find a wiring diagram on web.

Thanks, Trebor

 

[Svard75]

That's a great start. I would perform a coolant flush and while its empty clean the sensor. If the coolant was never flushed it could be corroded.


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[dietz4ibanez]

Welcome to the site! Did you get anywhere with this?

 

[JohnnyWinterdaal]

I had same problem. A quick solution was always to disconnect the battery cable (Prefer Negative Cable for safety reason) for a couple of seconds and reconnect. This resets the computer and voila. After replacing the THERMOSTAT the problem stayed away. most probably the thermostat gets stuck in OPEN position and the engine does not register the right temp.

 

[Kbulldude]

I’m having this same issue. I’m receiving a P0118 code that will not clear and immediately shows back up after clearing and key is in on position. I also have the “engine hot a/c off” on the instrument cluster”. Temp gauge is pegged at cold and both fans stay running. I’ve changed the temp sensor and thermostat. I have 5 volts at the coolant temp sensor harness and not sure where to go from here. Any help would be greatly appreciated.

 

[dmaxweb1]

Where is the temperature sensor on 2011 Equinox 2.4l ?

 

[TARDIS B]

This would happen in my 2010 Silverado when the thermostat would need replaced. Just means thermostat is worn out and stuck open. I ran across this post searching for info on a coolant flush for my 2015 equinox. Never done one without a radiator cap.

 

[cavell]

Darn, old thread. Had same issue. The thermostat is stuck open. And you then get a hot motor error. Code 0118 cold and 0128 hot? Can’t recall exact code. But GM wants you to fix it by giving you dire warnings. Change the thermostat.

 

[cavell]

Already answered. Darn, old thread. Had same issue. The thermostat is stuck open. And you then get a hot motor error. Code 0118 cold and 0128 hot? Can’t recall exact code. But GM wants you to fix it by giving you dire warnings. Change the thermostat.

 

[ponchoissean]

Solved!!!!
I put a 180° thermostat in when i replaced it a year ago. GM requires a 195° thermostat in this car. Once i put the right temp thermostat in, reset the battery, all the issue went away permanently.

 

[ponchoissean]

Already answered. Darn, old thread. Had same issue. The thermostat is stuck open. And you then get a hot motor error. Code 0118 cold and 0128 hot? Can’t recall exact code. But GM wants you to fix it by giving you dire warnings. Change the thermostat.

Thermostat is not stuck open, it’s opening at too low of a temperature. Has to have a 195° thermostat. The autozone gold (crap) is only 180° and so are many others. Replace thermostat with correct temp is the real solution.

 

[cavell]

OR, your dash gauge is flaky.

 

[ponchoissean]

OR, your dash gauge is flaky.

This is bad advice for this issues ^. This is a common problem with a known solution. Put a 195° thermostat back in it and your problem is solved. Suggesting the gauge is bad is general troubleshooting idea that is not specific to this issue. I speak from experience having just solved this problem in my Equinox.