Engine coolant temp sensor and air conditioning problems!

[garyh80]

I have a 2007 cobalt 2.2 liter and I was wondering what this issue might be. The check engine light goes on, and my coolant temperature doesn't register. Along with the air conditioner not blowing out any cold air. This is very frustrating and I was wondering if anyone can give me some insight.

Thanks, Gary

 

[Rick.Mopar]

Yep I have the same Issues now and again, same exact trouble!!!!! I changed out the temp sensor, time will tell.

Gary, hook up a ODB scanner and see if you can see the temp on the scanner. On my car the temp sensor doesn't read anything but on the scanner I can read the temperature readout.

 

[Four Fingers]

I am going through this exact same thing with check engine light and collant temp not showing, although temp is back on and check engine light off after i went to advance auto parts and had them plug into my computer to find out what was wrong. is there a write up on replacing the temp sensor? or is this better left to the expert mechanics?

 

[bigstar101]

I have somewhat a similar issue...
with my 2008 Cobalt 2.2L reading faulty temp. It will surge to 230 whiles its normal.
What prt do I need to buuy and does anyobody have a manual or how to locate and swap the coolant sesnor

Thankss

 

[YelloEye]

I vote you need to flush or purge your coolant system, depending on mileage either your coolant is old or you need to get the air bubbles out of the system.

 

[sjackson4]

I'm having a similar issue with my temp coolant tuning on and off. When I take off in the mornings my coolant temp will turn off after about ten minutes. In the afternoon on my way home the sensor will still be off, but will turn back on after about ten minutes. If it runs off any other time I will have to wait until the car cools until it will reset after the ten minutes. The sensor was changed. It sounds like an electrical problem, has anybody seen this before? It did this before about a year ago then stopped and now it is doing it again. I've also been thinking that may have to do with the humidity,

 

[futchstien]

@sjackson4, I have the EXACT same problem wrong with my 2008 Cobalt. I'm starting to think it's a bad coolant sensor, but I'm not 100% sure. Did you ever find out what the problem was?

 

[sjackson4]

Dashes on engine coolant reading.

It turned to be the thermostat was leaking by just enough to lower the engine temp a little. When you start your car it has meet certain criteria to run a diagnostic. With my engine coolant reading low it would change my coolant temp in to dashes after about minutes in cool weather. In cold weather there is a minimum temp to run the diag, if it is below that temp it will not run the diag. so it gives no issues and in hot temps it will pass. After over 2 years of thinking it was an electrical problem I finally just changed my thermostat and the problem hasn't shown up again. When the ECM can't read coolant temp it will shut off the AC compressor.

 

[futchstien]

Can confirm. I ended up replacing the Thermostat on my 2008 cobalt for $16 on Amazon and no longer experience any problems. Credit @sjackson4 for the help!

Link for Thermostat I bought:
http://www.amazon.com/gp/product/B000C822Y2/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

 

[Blaine23]

My thermostat was replaced last month which fixed this issue up until yesterday now the ac isn't blowing cold again and coolant is now showing ---°f any idea's?