A/C Off Due to High Engine Temp

[PQ]

Nothing wrong with the thermostat. Put it in water and it opened when it should when heated.

I'm at a freaking loss. I reset the ecm so it's running correctly but I already know it will happen once I drive it a bit.

Now I have 3 holes to dig.

[DarkMaroSS]

I had this same problem yesterday for the first time and when the weather down here got cold. Not the first time the weather here drops to 45 degrees and I drive the car without issues. Here is the thing, the message came up, the temperature gauge dropped to cold, no engine temperature reading on the digital cluster, and no dtc when I checked with my X4, and the radiator was full. After reading this thread it made sense that it could be due to a misreading from the ECM (out of range reading) along with having the 160 deg thermostat, so decided to first try by resetting the ECM by pulling the fuses and leave it over night. Before I pulled those two fuses, while my car was sitting in my garage turned off, the message would still come up and like I said the engine not running. I put the fuses back on this morning and turned the switch to use accessories and no message, the ECT was reading the lowest coolant temperature being 64 degrees as the engine wasnt running, turned on the engine while datalogging with the X4 and ECT readings were working. Drove the car close to my area to see if the temperature kept reading and it went to its usual reading of 192 degrees like it does on a stop and go drive, and before that I noticed the usual reading behavior the car has when the thermostat opens up, but haven’t tested on a long drive. When it happened yesterday I was just getting to 80mph after getting into I-595. Has anyone finally figured this out?

[WoodBoss]

I'm having the same issue, I have a 160* Thermostat as well. it's been cold here and runs cooler in the winter about 160*, I guess this is what is causing the ECM to give me that message. I have replaced a couple coolant temp sensors now and probed the coolant with a thermometer, it's never over heated and the oil temp sensor in the cluster always reads in the normal range it always had. I didn't have this issue when the car ran about 180* in the summer with the 160* thermostat.

[WoodBoss]

I checked with DynoSteve about changing my tune but he said if he alters the tune to stop that code from coming up it could cause other issues. I guess the only way around this is not to drive with a 160* thermostat when it cold out or put the stock stat back in for winter driving. I reflashed the ECM and the gauge started to work again, at least I know it's not the wiring or the sending unit.

[Bretts]

same problem fan runs right away pull it outside both fans on and no ac car does not over heat ,no ac

[Bretts]

Originally Posted by PQ

Nothing wrong with the thermostat. Put it in water and it opened when it should when heated.

I'm at a freaking loss. I reset the ecm so it's running correctly but I already know it will happen once I drive it a bit.

Now I have 3 holes to dig.

any luck#hide the cat

[jdpeezy91]

Just started to have this issue this morning on my 2012 SS so guess im gonna start hunting it down sucks im out of town for work no tools hopefully i can get it fixed and it gets me home Friday seems like chevy jas aloy of issues with sensors at 29k miles my oil pressure sensor started bleeding oil pretty good and had to be replaced

[jdpeezy91]

Just checked the coolant temp while off with my sct getting a reading there so not the temp sensor like i had hoped the rad is 100 percent full the overflow bottle is at minimum with engine cold anyone can point me to the correct wire to pull to reset the ecm theres alot of wires going on over by the fuse box i dont wanna pull the wrong one and have the whole car explode

[WoodBoss]

Originally Posted by jdpeezy91

Just checked the coolant temp while off with my sct getting a reading there so not the temp sensor like i had hoped the rad is 100 percent full the overflow bottle is at minimum with engine cold anyone can point me to the correct wire to pull to reset the ecm theres alot of wires going on over by the fuse box i dont wanna pull the wrong one and have the whole car explode

Might be easier to disconnect your battery for a bit or reflash your tune if you have a handheld tuner like an SCT.

[Bretts]

I pulled the wires from the 3 wire pressure sensor on the high pressure line right below cold air intake pipe so driver side top of rad area my AC kicked on right away I'm thinking I've got a pressure switch or a wire issue at that point not sure if it was wise to do but frustration ruled and ecm still ok

[jdpeezy91]

The temp never over heated according to my sct data logs after driving it around a bit the cars back to normal now temp gauge is working ac is working just went away still dont know what caused it just another thing to worry about

[Bretts]

ordered the pressure sensor switch 40 bucks and self sealing threads ,as it has a shraeder valve it screws into

[Polarbear99]

I'm just not starting to get the issue with my car I already replaced the thermostat cause the engine was running to cool. Now I have this issue do you think replacing the coolant thermo sensor would help fix this? If anyone has done this can you please let me know if this worked out

[Polarbear99]

Well put the new sensor in the car. Took it out for a test but the real test is tomorrow morning when I head to work. That's when I get the error.