I have been having this problem for a week now with my car that shows coolant temp XXX and the A/C cuts off. My coolant was running around 160 degrees when I get this message saying HOT Engine Air conditioning off. Sonetimes it gets the message right when the car is started. I disabled PO128 DTC (Coolant temp Below Thermostat regulating temp) in my Hptuner. It helped for about 5 minutes now it is back. Anyone else having this problem? My 160 stat has been in the car for over 3000 miles and has never had an issue. I reflashed the computer with a fresh tune, left battery off for a day. Please help !!

 

It's the computer having issues reading your coolant temp. It's readiing the temp is too low....

You have an aftermarket T-stat right? You can disable the error code with tuning...

 

I had a Mr. Gasket 160 T-stat that caused this problem . I changed out to a Lingenfelter T-stat and no longer have any issues. Some T-stats just won't allow the car to get up to temp and then you will get that message and the fans will run nonstop!!

 

The error code is disabled but the message still comes up. Is there another place in the tune to change the range or disable the hot message. When the message is up the A/C is out and all shift parameters change etc etc. I cant be the only person that has had this problem. The 160 stat has been in the car for over 3000 miles

 

burp the system. Do a search on this but there could be an air pocket where the sensor is and it thinks the car is hot. I think you take the rad cap off run the car up to 2K rpms for several minutes while massaging the upper rad hose and add coolant as needed. Reasearch this first though.

 

Disabling the error code does not "Fix" the underlying problem. You've mentioned the Stat has been in for 3000 miles...What temp does the car run at? it should be 180-185. Many 160 stats, as mentioned, are faulty and keep the car at a 155-165 temp range which will get this message. Burp your system, check the plug on your temp sensor. There's a possibility that it may be bad.

 

It has been burped a few times. It seems to be fine.

It runs at 190ish most of the time. It started on a cool night we had.
The car ran at 165 for a while. Where is the temp sensor located?

Thanks guys

 

Drivers side Head......Front left side

 

Thanks man

 

I had the same error message, but mine was caused by a defective 160 degree thermostat. I tried two Mr. Gasket thermostats both of which didn't operate properly. When I bench tested them they began to open at 140 degrees rather than 160 degrees. In fact both of them were fully open by 160 degrees. I switched to an SLP 160 degree thermostat and have had no issues since. And I tested it before installing. You may want to try bench testing your thermostat to check if it is operating properly. At least then you could rule it out as being a problem.

Also it is my understanding that the coolant temp must reach at least 167 degrees when the car warms up or the computer will be fooled into thinking the car is overheating. If you ran the car on a cool night and the temp never got above 167 degrees that could cause the error message. Sounds to me like it could be a faulty thermostat. What brand are you using?

Also in summer weather even if you have a defective 160 degree thermostat you might not know it as long as the coolant temps get up above 167 degrees. You would however notice a problem in cooler weather because the car would take longer to warm up or wouldn't reach the minimum operating temp. With the defective thermostat my car was running in the upper 150s to low 160s on the highway. If the temp didn't get up to at least 167 before I got on the highway I would get an error message. In town the car ran warmer so it wasn't a problem there.

 

Had the same problem happen when I installed a Mr. Gasket 160 stat in my friends 07. For some reason these stats run cooler than others. Changed over to a Lingenfelter and that corrected the error message.

 

I have a Mr. Gasket Thermo in it. Seems like it is the problem child. I will lower my fan temps until I can get a new stat. Where is the best place to buy one?

 

I purchased my SLP 160 degree stat online from Summit Racing. I purchased one of my Mr. Gasket thermostats from them too.

 

I bought my SLP 160 from Maryland Speed and had it to my door within a week (I live in Colorado, so that's not too bad w/ UPS ground).

Cheers!