[MamaYoda]

I have a 2009 GMC canyon slt with the I5 engine. Driving today, the AC off message came on the dash and I noticed the temp gauge isn't registering any temperature. Pulled into the nearest gas station and checked stuff out. Coolant is at good levels, engine is not over heating at all. To be honest engine is not hot at all. I was able to touch the radiator and hoses and they just feel warm. Is this my thermostat that's causing the issue? Gonna run to Auto parts store and see if it's throwing any codes. Any insight to this issue would be very much appreciated. Thank you

 

[OldTime]

I have a 2009 GMC canyon slt with the I5 engine. Driving today, the AC off message came on the dash and I noticed the temp gauge isn't registering any temperature. Pulled into the nearest gas station and checked stuff out. Coolant is at good levels, engine is not over heating at all. To be honest engine is not hot at all. I was able to touch the radiator and hoses and they just feel warm. Is this my thermostat that's causing the issue? Gonna run to Auto parts store and see if it's throwing any codes. Any insight to this issue would be very much appreciated. Thank you

If this issue were going to throw a code you would have seen it on the display. Most likely you have a stuck open thermostat.

 

[MamaYoda]

Thank you. Yeah that's what I'm thinking. Stupid part is that I can't just buy the thermostat. Looks like it has the housing with it. So now a 10 dollar part is now 50 to 60 ughhhh. Oh well.

 

[OldGuy]

If the gauge isn't working, it's probably the temperature sending unit. That part is only about $30. You can test the sensor with an ohm meter after removing it, or with a volt meter while it's installed. Your gauge on the dash is basically an ohm meter. Voltage passes through the sensor and as the engine warms up the resistance either increases or decreases - depending on the vehicle. Your gauge basically measures this change. The A/C turns off when your truck overheats to prevent damage. If the computer has no idea what your cooling system is doing, it defaults to this safe mode of turning the A/C off. If it's not running hot you either have significant air bubbles in the system, or a bad sensor. If you haven't recently drained the cooling system to replace a hose or something, then I would replace the sensor.
Here's a video on how to replace the sensor.

Good luck!!

 

[macgyver915]

I have a 2009 GMC canyon slt with the I5 engine. Driving today, the AC off message came on the dash and I noticed the temp gauge isn't registering any temperature. Pulled into the nearest gas station and checked stuff out. Coolant is at good levels, engine is not over heating at all. To be honest engine is not hot at all. I was able to touch the radiator and hoses and they just feel warm. Is this my thermostat that's causing the issue? Gonna run to Auto parts store and see if it's throwing any codes. Any insight to this issue would be very much appreciated. Thank you

My 2008 Colorado has down that and I don't remember the code that caused it, but what the code I got basically indicated was that the engine temp didn't rise a certain amount within a certain time after starting up the truck. My understanding is that a thermostat that is stuck fully or partially open can cause it, and it tended to happen more in the winter when I would get on the interstate quickly after starting out. I think a combination of cold weather and interstate speeds (along with the thermostat problem) is enough to throw the code. When it happens, I reset the code and the issue goes away till next time - maybe a week or maybe a month, but it hasn't done it when the weather is warmer. I just haven't taken the time and effort to replace the thermostat, as it seems to be a major hassle and my understanding is that the code isn't really causing any lasting problems.

 

[CR>AUTODETAILING]

It is indeed the thermostat. My truck did the same thing. It happened on the coldest day in Connecticut of course

 

[Unfettered]

As others said..Thermostat. I had mine replaced when it was in for other service at a dealership. I didn't remember it being more that about $125 for the thermostat and flush and refill. I can't do as much of my own service work anymore.

 

[OldGuy]

The more I think about it, the more I agree. But a scan tool would let you know for sure. My temperature gauge never got above about 1/4. I assumed I had a thermostat problem, so I did the old school test of taking it out and putting in on the stove in a pot of water with a thermometer in it. The thermostat was working perfectly. I then hooked up my Scangauge II and could read the coolant temperature and it was right where it should be. The truck's computer reads the temperature sensor, not the gauge. If you had access to a scan tool that reads coolant temperature, you could see if the temperature is within normal range, or if the sensor is not working correctly. In a pot of water on the stove, I watched my thermostat open at about 195 degrees and when I turned the stove off, the thermostat closed at about 185 degrees. This is a pretty simple test, but obviously, you have to go to the trouble of taking the thermostat out. You also have to take on the risk of your wife catching you boiling car parts in her pot and on her stove!! After 34 years of marriage though, my wife has gradually learned to tolerate my strange behavior!
Good luck, and let us know what you find.

 

[Jaymes]

I agree with everyone that said it's the stuck open thermostat. Mine had the exact symptoms and a new thermostat fixed it.

 

[krampn17]

So yourself a favor and pay a shop to do your thermostat. It is extremely difficult to get to. You have to take a wheel off and are left with a tiny opening to get tools in. You need a really long socket to get the bolts off and there is a clamp holding the hose on the thermostat that I had lots of trouble getting off and getting back on.

 

[OldGuy]

I didn't think it was a bad job, and I didn't remove the wheel. I did basically what they did in this video, but I did take the time to mark my thermostat location before I took the thermostat off of the hose since my hose was not marked like the one in this video. I just removed the fender liner and jacked up the front of the truck a little. If you have oversized wheels/tires, you probably will have to remove the wheel though.