Ok, my 07 Equinox suddenly started saying this on the dash and I noticed the temperature gauge isn't working at all. It did this first thing on a cold morning so I knew it wasn't really overheating but that it must just not be receiving a temperature from a sensor and it's going into some kind of safe mode and running the fans at full blast and turning the AC off. Well I went and bought a coolant temperature sensor yesterday.. there were 2 different ones listed for an 07 3.4L and maybe I just replaced the wrong one. One was $15 and one was $23 and the guy at Advance Auto Parts (who usually don't know what they're doing, I know) says I need the $23 one. I find that it's on the driver's side of the motor and it's pretty easy to swap so I do. It looked like it may have been on the head but it could've been the block too (hard to see) from that angle. I know it wasn't right on top of the hose neck that goes to the radio (and where I expect the thermostat to be). I unhooked the battery so the ECM would reset the CEL on the dash and when I hooked it back up and restarted the gauge worked perfectly fine and no message about engine over heating. I was glad it was just a $23 sensor. Well then I drove for about 5 minutes and it did it again. I watched the gauge just drop off from about half-way up down to zero and the ENGINE HOT A/C OFF comes back on the dash.
Any tips? Is there a second sensor? Is it the one for the gauge on the dash? Why would it work if I reset the ECM but then quit working a few minutes later? Makes me think it could be an ECM problem because the sensor is dumb and should either work or not work and not be affected by the ECM resetting.
I appreciate any help. The closest dealership is 45 minutes away and I'm not ready to pay them $100 or so just to diagnose this problem, let alone fix it.
Any tips? Is there a second sensor? Is it the one for the gauge on the dash? Why would it work if I reset the ECM but then quit working a few minutes later? Makes me think it could be an ECM problem because the sensor is dumb and should either work or not work and not be affected by the ECM resetting.
I appreciate any help. The closest dealership is 45 minutes away and I'm not ready to pay them $100 or so just to diagnose this problem, let alone fix it.