Well just changed the temp sensor, not to hard if u have the right tools, but didn't solve my problem. I guess I'm gonna have to change the thermostat next, sucks!

 

We'll I've changed both the temp sensor and the thermostat, and still have the same issue. Does anybody have a sure fix? Besides trading it in for something else.

 

** Radiator didn't do it but the thermostat and housing did fix my issue. Has been working for about 6 weeks.

 

Forgot to post this earlier, but the following day after replacing the thermostat ac started working, temp gauge is working like normal, and has been working since then. It's been over a week now and no issues. Hopefully it stays this way.

 

Good to hear, nice work.

 

congrats bro.

your AC started working after codes were cleared by next day

thats the only reason

enjoy the cool breeze

 

My AC OFF message came on and my temperature gauge dropped to 0. After reading this forum, I removed the PCM-B fuse and put it back in. Everything started working correctly. My check engine light had even been on for several months, and now it is off. Hope this helps someone else.

 

I've got a 2008 inline 5 cylinder H3 with around 142k miles on it. Had the AC off message problem where the engine temp gauge wouldn't reach operating temperature and it would tell me I couldn't run AC.

I replaced the thermostat and the temperature sensor and the problem went away for a few months.

The problem has returned. When I start up in the morning the temp gauge doesn't go but a mm above the bottom mark before dropping completely. By the time I get home the engine is up to temp (the gauge still shows nothing and the message is still present) and I can clear the message by either disconnecting the battery or pulling the PCM-B fuse. When I start the engine the temperature gauge immediately reads like its' supposed to, AC works, everything is good. I'm having to clear the error every time I want to drive after it's been sitting for a few hours. Has anyone else had this? Is there any other thing I should try? I confirmed the thermostat works by reving the engine at idle and observing the coolant flow. If the sensor was bad, wouldn't it still not give a temperature reading even after cycling the PCM-B?

 

FYI, you cannot "clear" anything by disconnecting the battery/pulling a fuse. Late model GM vehicles retain the last 300 ignition cycles, regardless of power interruptions. All you are doing is turning off the fault until the PCM recognizes that the fault condition still exists and creates the same symptoms. Those symptoms are screaming.... come look at this it is messed up!!!

The temp sensor is an electrical part, it senses heat and relays voltage which is displayed as temperature. If the CTS it is defective, it can work at times, and not others because the PCM cannot interpret voltage beyond the pre-programmed expected range. In other words, its short may not be consistent over time, it may be high, low, or dead. Think of a flickering light bulb, it may work for a couple days before it completely pukes.

If you are sure it is reaching proper temp., Coolant Temp. Sensors are cheap and easy. Try that.

 

hi I have the same problems ...so the ac off will appear on my dash and temp gage will be down but will comeback if I play around with the ac swith for few min and w
stay on (AC FULL COLD) but the next day after starting the car for 10 min will goes off again and back to square one ...please help