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merf23

Engine Hot A/c Turned Off Code - Not Really Hot

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I have a 2008 1500 4x4 4.3 V6 with 40000miles. Recently the ENGINE HOT A/C TURNED OFF warning pops up, but the engine isnt really hot. It seems to reset itself after a while. I though it did it more in wet weather, but today is dry (though yesterday rained). It did this yesterday. FIrst i disconnected the temp sensor on the left head, then reconnected it. It looked clean. This did nothing. Then, I disconnected the battery, and when i reconnected it 20 min later it was back to normal. I drove about 20 minutes twice today, at the end of the second trip it did it again. There was a recall to remove the insulation from the under seat computer, which i had done. It had the problem prior to this, and still does. Its probably occurred 10 times in the last 6 months, 7-8000 miles.

 

DO i justs need a temp sensor, or is it possible more involved?

 

thanks

Sean

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I have a 2008 1500 4x4 4.3 V6 with 40000miles. Recently the ENGINE HOT A/C TURNED OFF warning pops up, but the engine isnt really hot. It seems to reset itself after a while. I though it did it more in wet weather, but today is dry (though yesterday rained). It did this yesterday. FIrst i disconnected the temp sensor on the left head, then reconnected it. It looked clean. This did nothing. Then, I disconnected the battery, and when i reconnected it 20 min later it was back to normal. I drove about 20 minutes twice today, at the end of the second trip it did it again. There was a recall to remove the insulation from the under seat computer, which i had done. It had the problem prior to this, and still does. Its probably occurred 10 times in the last 6 months, 7-8000 miles.

 

DO i justs need a temp sensor, or is it possible more involved?

 

thanks

Sean

 

 

Do you have a block heater?

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no block heater...Connecticut isnt quite that cold.

 

it did it again. i disconnected the battery for 1 min, and that reset it

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no block heater...Connecticut isnt quite that cold.

 

it did it again. i disconnected the battery for 1 min, and that reset it

 

This problem is all over the internet but I have yet to see a reasonable fix posted. I see some say to replace the thermostat, but the temperature guage drops to lowest reading instantly, which tells me that the engine temperature is not actually changing. Plus the problem can linger a few days and then the guage will instantly jump to a correct reading and all will be ok, until next time. some have said they have replaced the temperature sensor with no luck. Does anyone know the answer or can they explain how the thermostat can cause this to happen? I am thinking the computer must be involved in this somehow.

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If the engine was hot 255F or higher the PCM would have a code and the SES light would have been on. I suspect a electrical problem possibly the cluster. BTW the PCM is not under the seat its in the engine compartment.

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My truck had the same problem the thermostat was replaced under warranty no problems since...good luck.

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I was just going to post the same problem with my buddies 2008 Impala....probably the same issue

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Here is my situation. 4.8l v6. 2008. Truck has no issues as long as the outside temp is about about 75*. Once temps go below that I have problems. I leave to go to work and truck has sat all night. Once I drive about 7 miles the temp guage goes from normal to nothing and my A/C wont work. If I disconnect the battery the guage goes back to normal and the A/C works fine until the next morning. Also if I don't disconnect the battery I can get on the highway on the way home and it will start working within 100 yards of the same place every day. I have no problems in the summer, but on the coldest days after sitting all weekend it shows engine hot. It has got to be something to do with the ambient temp.

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I have found This is a common problem. GM engineers have apparently decided that if the engine temperature is too low (example 195deg) that they will display "engine too hot turning ac off". I had the same problem and replaced the engine temperature sensor but that didn't fix the problem. I had GM replace the thermostat and that fixed the problem. It doesn't make sense to display this on an engine that is too cool, but that is how it works.

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This happened to me three times in my 2008 Silverado (4.3 V6). I took it to the dealer and they replaced the thermostat free of charge under the powertrain warranty. Aggravating, but at least it was a free fix.

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I have a 2007 Chevy Silverado, with this same issue, I have changed the thermostat twice and it still keeps happening. Last Thermostat change the error did not happen for a few months but started up again and we finally have cool weather. Stopped unplugging battery to reset and when the weather is cold in the morning the temp guage will start up on it's own again, but the warmer the day gets or the longer drive the truck it comes back on, very annoying any real answers for the fix out there.

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I Have the GMC Sierra 3500 HD with a Vortec 6.0L . I've faced this problem well over a year now, and i only encounter its appearance after it rains, while in summer the engine works perfectly. i knew that the problem is back only from the temp gauge going lower to 90 degrees when its normally 100 (Celsius because I'm in Dubai) but i know the normal engine temp is 100. I've changed the thermostat earlier but the problem wasn't fixed, i cleaned out the battery wires after it then the problem was fixed for well over 9 months. And now the problem is back and its taunting me and really really pissing me off. Please HELP me because its my daily driver truck and i just wanna get over with this shit and get it fixed. One trick i keep doing when this appears is that i disconnect the Battery wires and reconnecting again then the problem is fixed for a few hours, then its back again. The temp here in Dubai is over 40 degrees Celsius and i always boil while driving, Hell i even had to do the battery trick even when i was on a date. TWICE for gods sake, she never called again....

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Hi everyone,

 

This is to help whoever can benefit from it.

 

First my background. 28 years as an ASE Master, L1, CA Smog Tech, B & L Inspector. Been doing this way too long!

 

This same issue started six months ago on my personal truck but it was very random to say the least. The problem would always disappear by the time I got to my destination until last week. Going by the symptoms, I knew this was a electrical/electronic problem and not a mechanical (thermostat) problem.

 

My diagnostics lead me to the BCM. Problem is that as soon as I touched the wire harness going to the BCM the fault disappeared and has not returned. I did however unplug and inspect for signs of poor connections and broken wires at the BCM. I have seen way to many times that wires will break inside the insulation due to excessive stress caused by engineers. The harness is very tight going to the BCM connectors. I hope this helps some you and I will add more if my ghost shows up again.

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Bought a 2011 Silverado a few months ago, same problem. Changed the thermostat to be certain and there was nothing wrong with it. Now I have a flashcal and I checked the engine temp when this A/C off code came up and the temp is just fine 168 at the moment (even though the needle stays at 0) No other codes or problems. Like you I suspect it's wiring or a connection. Thanks for the heads up, I'm going to see if it's around the BCM as well.

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On my way to work I received the same error again. I reached my left foot up behind the dash and tapped a wiring harness and immediately the error disappeared and the gauge went back to normal. Now to figure out which one it was.

Edited by 11BSilverado

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Unfortunately the gremlin came back for about 5 minutes while driving to work. I did have my Verus all hooked up and ready. I was able to see the ECM was reading the ECT at 172 but as soon as I switched to the BCM the fault disappeared. Coincidence? No idea yet as that little &%[email protected]* gremlin has not showed its ugly head again. I will follow up when it does.

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