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2008 Chevy Silverado Engine Hot Light
February 4th, 2014, 10:09 PM
#21
Hi everyone, I'm new to the forum. I hope everyone is well. Can anyone provide a status update on the engine hot/ac off error message? I just started getting it today. Isit safe to say the thermostat is the problem? Thanks.
March 28th, 2014, 10:27 AM
#22
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I've had the exact same problem with my Chevy, engine hot/AC turned off message, fans running. I just changed out the thermostat this morning, started it back up and there is no change, the message is still there and the fans are still running. What next?
March 30th, 2014, 8:40 AM
#23
Wow; Thats interesting. the thermostat seemed to have fixed the problem for me. I did speak to the service guys at one of the the dealerships here in town before I fixed it and they said the thermostat was the "most common" solution to the message. They did not say what other causes may be.
April 3rd, 2014, 6:55 AM
#24
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Code P0128 Engine hot /A/C off
This came up on my 07 silverado today I cleared the code and tempature gauge started back working and message went away.I will change the thermostat and see if that clears it up. Thanks for all the information.
April 4th, 2014, 8:10 AM
#25
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Fixed
So it looks like the thermostat change worked after all, or maybe all I needed to do was clear the code. Unhooked the negative battery cable for about 30 sec then reattached, fans stopped coming on and temperature gauge back to normal. At least I have a new thermostat in there I guess.
August 9th, 2019, 7:38 PM
#28
you can add me to the list of folks with this problem.
2008 silverado , 4.3L engine with approx 50,000 miles.
Things that i can confirm.
-the engine is not running hot ( 205-210 F)
-the sensor works fine ( the old one and the new one i replaced it with)
have the same resistance at operating temp
- the connector and wiring to the ECM do not appear frayed or corroded and always show good ohm values.
- the coolant levels are full and well purged.
- when the error message appears the temp gage is deactivated even though the sensor is still functioning and the radiator fans are powered (clearing the codes immediately returns the temp gage to prior level)
-The ECT sensor provides input for both the ECM and temp gage on the dash.
(i believe the ECM (control module) is deactivating the dash temp gage )
- if i disconnect the ECT sensor, it will generate the same error message.
after reconnecting the ECT (temp sensor), the message clears, temp gage, radiator fans and A/C functionality are restored.
not clearing the code after the error message occurs eventually creates an OBD error (P0128) along with 'check engine light'. At this point, Freeze Frame data read by scanner says ECT temp is too low (167F) . I'm sure that is because both radiator fans are maxed out as soon as the ENGINE HOT message first appears and the thermostat can't keep up.
Things i'm not too sure about:
-Changing the thermostat seems to work.
despite the fact that it raised the ECT by a approx 5 degrees to 210F.
at present I've only made a couple of round trips to work since replacing the thermostat w/o any nasty messages. However, prior to the change, i was tripping the ENGINE HOT message on both legs of my commute for over a week.
_so i am hoping that was enough to make the problem go away.
the message appears to be a bogus programed response to the warm up cycle of the truck. either the thermostat has been steadily failing or the recent colder outside temps have kept the ECT from reaching some predetermined level in the ECM. or worst case the ECM is the part thats the ultimate cause of all this.
I'm keeping my fingers crossed for the thermostat.
-bill
2008 silverado , 4.3L engine with approx 50,000 miles.
Things that i can confirm.
-the engine is not running hot ( 205-210 F)
-the sensor works fine ( the old one and the new one i replaced it with)
have the same resistance at operating temp
- the connector and wiring to the ECM do not appear frayed or corroded and always show good ohm values.
- the coolant levels are full and well purged.
- when the error message appears the temp gage is deactivated even though the sensor is still functioning and the radiator fans are powered (clearing the codes immediately returns the temp gage to prior level)
-The ECT sensor provides input for both the ECM and temp gage on the dash.
(i believe the ECM (control module) is deactivating the dash temp gage )
- if i disconnect the ECT sensor, it will generate the same error message.
after reconnecting the ECT (temp sensor), the message clears, temp gage, radiator fans and A/C functionality are restored.
not clearing the code after the error message occurs eventually creates an OBD error (P0128) along with 'check engine light'. At this point, Freeze Frame data read by scanner says ECT temp is too low (167F) . I'm sure that is because both radiator fans are maxed out as soon as the ENGINE HOT message first appears and the thermostat can't keep up.
Things i'm not too sure about:
-Changing the thermostat seems to work.
despite the fact that it raised the ECT by a approx 5 degrees to 210F.
at present I've only made a couple of round trips to work since replacing the thermostat w/o any nasty messages. However, prior to the change, i was tripping the ENGINE HOT message on both legs of my commute for over a week.
_so i am hoping that was enough to make the problem go away.
the message appears to be a bogus programed response to the warm up cycle of the truck. either the thermostat has been steadily failing or the recent colder outside temps have kept the ECT from reaching some predetermined level in the ECM. or worst case the ECM is the part thats the ultimate cause of all this.
I'm keeping my fingers crossed for the thermostat.
-bill
August 5th, 2021, 8:11 AM
#29
I've changed everything!!
I have a 2008 chevy silverado 5.3. About 6 months ago the temperature guage started to act up and jump to max temp and a message would pop up "Engine hot ac turned off" followed by "Engine overheated throttle down". I would pull over and check the obvious. Coolant level, and bottom of oil cap and dipstick just to make sure I didn't blow a headgasket or losing coolant through a broken hose or line. Nothing.. Waited 30 minutes to cool down and it started and drive fine for the rest of the drive to destination and for about 2 weeks and it did it again. So then I changed the Engine coolant temp sensor and everything was good, for about 1 week, started doing it again, now I replaced the thermostat, took car of the issue and all was good for about 2 months. Then it did it again, and I'm like WHAT!!!! So I did a coolant flush and checked every hose, I checked the radiator I even changed the damn plugs and wires (COILS TESTED GOOD) just so I can see the old plugs and what the tips looked like. All looked and gapped within standard. I even replaced the ect and thermostat a second time just to rule out possible defect from parts store (ADVANCE AUTO). Everything seemed well for about 3 and a half weeks and started again. I was stumped at this point, I even stumbled upon this very forum when the problem originally occurred and this is where I found most of my solutions. So here I am back again 3 months later. Now I have sense did a leak down of the motor, pulled the plugs and ran a bore scope just to make sure I am not losing my mind, swapped ect and thermostat for a 3rd time, bought a new pig tail and replaced the old ect connector, changed my oil looked for leaks and checked coolant lines and even after all that it's still currently acting the same and you can be fine for a few hours and then it will act up, or you can just start the thing and it will do it instantly. I am beyond my expertise at this point!! I have zero ideas or conclusions as to how or why this is possible happening. I guess my next step is to chase the wires from the ect all the way to the ecm, and that Engine harness for a short or ground issue.. Aside from that I am at a loss.. Any help would be greatly appreciated!! Thanks
August 6th, 2021, 5:52 AM
#30
Have you checked the OBD codes?
the error message on the dash is obviously wrong. However the control module is responding to something it considers improper.
pull the codes and address those “faults”
in one of the original post on this thread the fault code (P0128, in my case) indicated that the temperature was not reaching the prescribed value fast enough.
essentially, according to the ECM, the engine was not too hot, it was not getting hot fast enough.
You may or may not have a check engine light at this point, but if you get the “engine hot” message on the dash you likely have at least one OBD fault that is pending. …..find out which faults are logged or pending and deal with them first. Clearing the codes will remove any significant clues to what the problem may be. However, clearing the codes will restore the temp gage function and turn off the fans….for a while,until the problem returns.
good luck
the error message on the dash is obviously wrong. However the control module is responding to something it considers improper.
pull the codes and address those “faults”
in one of the original post on this thread the fault code (P0128, in my case) indicated that the temperature was not reaching the prescribed value fast enough.
essentially, according to the ECM, the engine was not too hot, it was not getting hot fast enough.
You may or may not have a check engine light at this point, but if you get the “engine hot” message on the dash you likely have at least one OBD fault that is pending. …..find out which faults are logged or pending and deal with them first. Clearing the codes will remove any significant clues to what the problem may be. However, clearing the codes will restore the temp gage function and turn off the fans….for a while,until the problem returns.
good luck
Last edited by wgf; August 6th, 2021 at 6:04 AM.