engine hot ac off
November 29th, 2010, 9:16 PM
#1
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engine hot ac off
on dash where the odometer is this popped up engine hot ac off. the temp guage reads cold and stays on cold. the engine fan is running. whats going on?
January 22nd, 2011, 11:07 AM
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I have an 06 Impala w/ the 3.5 liter. It gives me the same message in the odometer space: "engine hot / AC off". I know the engine is NOT overheating. The warning light does not come on, heater works fine, no coolant running into overflow, or for that matter, running anywhere. This happened about two months ago for about a day or two and it "self-corrected". The message stopped and the gauge began to work again. If I had to guess, there is a sensor somewhere that has failed, is inoperative, or could be clogged with scale. New water pump & correct % of coolant/water. Anyone have any ideas?
October 16th, 2011, 2:56 PM
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I have an 08 Impala w/ the 3.5 liter. It gives me the same message in the odometer space: "engine hot / AC off". I know the engine is NOT overheating. The warning light does not come on, heater works fine, no coolant running into overflow, or for that matter, running anywhere.
October 16th, 2011, 3:30 PM
#4
Welcome to the forum.
A short in the ECTS circuit can do that. The ECT sensor is a thermistor whose resistance varies inversely to the temperature. The ECM supplies a reference voltage on one wire and ground on the other and then senses the voltage drop across the ECT sensor to derive the resistance. So, a short to ground (bypassing the sensor or short within the sensor) will translate to extremely high engine coolant temperature. ECMs usually contain logic to cope with the condition like turning the A/C compressor off, shut off half of fuel injectors, etc.
A short in the ECTS circuit can do that. The ECT sensor is a thermistor whose resistance varies inversely to the temperature. The ECM supplies a reference voltage on one wire and ground on the other and then senses the voltage drop across the ECT sensor to derive the resistance. So, a short to ground (bypassing the sensor or short within the sensor) will translate to extremely high engine coolant temperature. ECMs usually contain logic to cope with the condition like turning the A/C compressor off, shut off half of fuel injectors, etc.
October 19th, 2011, 8:48 AM
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EinST....what in the heck are you talking about? Have you googled "Engine Hot AC Off" and seen the thousands of postings about this issue. Do you think everyone of us have a short in the ECTS circuit? I'm not trying to sound rude but I have this problem with my 2010 Chevrolet Impala and it costs me $80 to have the dealership reset the codes on the dang car. They couldn't find any issues with the car so the fix was to reset the codes. Now...here's the million dollar question...how can the vehicle owner reset the codes without having to pay the dealership $80 a pop?
October 19th, 2011, 11:52 AM
#6
Welcome to the forum. It's really not rocket science but incompetence always triumphs. I actually do think it's the ECTS circuit (inside the ECM, wiring, and the ECTS itself) in majority of cases. What "codes" are you referring to that you had them reset?
It's really not rocket science but incompetence always triumphs. I actually do think it's the ECTS circuit (inside the ECM, wiring, and the ECTS itself) in majority of cases. What "codes" are you referring to that you had them reset?
October 20th, 2011, 9:23 AM
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I will see if I can scan in the service receipt that I got back when I took the car into the dealership. The "Engine Hot AC Off" warning actually turned off on my long commute home yesterday. Started the car up this morning and the warning signal came back on about a mile down the road and stayed on all the way to work this morning (75 miles). This issue is posted all over the internet on several different types of GM products.
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October 21st, 2011, 8:40 AM
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just happened with my 2010 impala last nite. DIC message warning popped up, gauge flat on "C". Car did not seem to be overheating. Defrost was on to clear windows. Dropped it off at dealer.
The owners manual just indicated that this mean coolant hotter than normal and ok ot continue to drive but get checked out soon to prevent compressor damage. Odd the car is running hotter than normal and the concern is on the a/c compressor??
Dealer just called as i wrote this, say diag indicates thermostat needs to be replaced. .. and oh, btw, you are due for tranny fluid mtc and FI cleaning for another 300$. Can't tell me and I don't know by the gauge if the car got hot enough to do damage or not.
It is hard for me to believe that with thermostat stuck in open position (he couldn't tell me how it was stuck) that the gauge would not move off C in the 25 miles i drove it (i did not really notice if before the light came on the temp guage was reading or not), so i am not sure what to assume regarding the temperature the engine may have reached.
I read that default for the computer is to assume the worst and declare engine is hot, but how is it, the thermostat goes bad and the guage doesn't read more than its coldest at the same time. I guess time will tell.
The owners manual just indicated that this mean coolant hotter than normal and ok ot continue to drive but get checked out soon to prevent compressor damage. Odd the car is running hotter than normal and the concern is on the a/c compressor??
Dealer just called as i wrote this, say diag indicates thermostat needs to be replaced. .. and oh, btw, you are due for tranny fluid mtc and FI cleaning for another 300$. Can't tell me and I don't know by the gauge if the car got hot enough to do damage or not.
It is hard for me to believe that with thermostat stuck in open position (he couldn't tell me how it was stuck) that the gauge would not move off C in the 25 miles i drove it (i did not really notice if before the light came on the temp guage was reading or not), so i am not sure what to assume regarding the temperature the engine may have reached.
I read that default for the computer is to assume the worst and declare engine is hot, but how is it, the thermostat goes bad and the guage doesn't read more than its coldest at the same time. I guess time will tell.
October 21st, 2011, 11:28 AM
#10
Welcome to the forum. They should be able to ascertain if the thermostat were indeed stuck open once they take it out. If it isn't, hopefully they'll check the ECTS circuit. Of course, it's hard to tell with warranty work. They usually lose money on those even with the diagnostic tools that make life so much easier nowadays.
They should be able to ascertain if the thermostat were indeed stuck open once they take it out. If it isn't, hopefully they'll check the ECTS circuit. Of course, it's hard to tell with warranty work. They usually lose money on those even with the diagnostic tools that make life so much easier nowadays.