Engine Hot A/C turned off P1258?

Tiny
ERRORMSG
  • MEMBER
  • 2009 CHEVROLET SILVERADO
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 53,400 MILES
Received a Engine Hot A/C turned off DIC message. Engine did not appear to be hot. Temp guage was at 160 degrees and the A/C was not running. Possible theromastat issue? This seems to be a known issue 'cause I see several post on the message. However; I don' see a clear resolution. Do you have a solution? Thanks for your help!
Tuesday, March 2nd, 2010 AT 8:49 AM

17 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Hello,

This can happen when the AC system is over charged which will trip the high pressure sensor for the system causing the AC engine hot warning. Here is a guide to help you with the problem.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

Please run down this guide and report back.

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Wednesday, March 3rd, 2010 AT 8:08 AM
Tiny
BUICK BOI
  • MEMBER
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The guy put too much Freon in it, let some out everything is great!
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Friday, August 23rd, 2019 AT 2:33 PM
Tiny
CROFT77
  • MEMBER
  • 1 POST
  • 2008 CHEVROLET SILVERADO
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 41,000 MILES
I am getting a message on my dash that say "Egine Hot, A/C Turned Off". My temperature guage does not seem to work, Both auxillary fans by the radiators run continuously. This message appears even after sitting 12 hrs in sub freezing temps.
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Tuesday, June 1st, 2021 AT 6:27 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
Tis happens when the AC pressure sensor goes out, here is the location so you can replace it. Check out the diagrams (Below). Please let us know what happens.
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Tuesday, June 1st, 2021 AT 6:27 PM (Merged)
Tiny
ESTILL
  • MEMBER
  • 1 POST
Yep this was the problem for my truck, thanks.
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Tuesday, June 1st, 2021 AT 6:27 PM (Merged)
Tiny
DISPATCHER521
  • MEMBER
  • 1 POST
  • 2007 CHEVROLET SILVERADO
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 70,000 MILES
I was on my way to work this morning when I heard the warning bell in my pickup go off I looked down and saw the message engine hot / ac ( air conditioning) turned off. I pulled over open the hood and looked around the the engine at the belts, water reservoir, water pump & hoses and did not notice anything out of place so I got back in the truck and looked at the gauges I noticed that the temp gauge needle was laid over not showing any increase in temperature at all so I took one more look under the hood and still saw and heard anything strange so I my pickup back to my hove about 13 miles away and went on my way to work after work I took a look at my truck one more time under the hood and still did not see anything out of place so I turned my pickup on and notice the same warning message come up as soon as I turned it on I got a small hammer and banged on the thermostat housing a couple of times just to see if anything would happen but nothing did so I turned the truck back off and here I am hoping someone can give me useful information on the problem.

Thank you
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Tuesday, June 1st, 2021 AT 6:28 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,700 POSTS
This will happen when the thermostat sticks closed. Here is a guide to help you step by step with instructions in the diagrams below to show you how on your car.

https://www.2carpros.com/articles/replace-thermostat

Check out the diagrams (Below). Please let us know what you find.
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Tuesday, June 1st, 2021 AT 6:28 PM (Merged)
Tiny
AMAZINBLAZIAN
  • MEMBER
  • 3 POSTS
  • 2006 CHEVROLET SILVERADO
  • 4.8L
  • V8
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
Getting an engine coolant hot message on my truck. Changed out the thermostat, ECT sensor, water pump and two hoses. Still getting the message after I drive the truck for five to ten minutes. No leaks found with nothing strange in the oil. Just noticed my heater is not working now. Can the heater core be affected? Or is it affecting the engine's temperature? Has anyone seen this?
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Tuesday, June 1st, 2021 AT 6:28 PM (Merged)
Tiny
HMAC300
  • MECHANIC
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It is probably low on fluid that is biggest reason heater not working. It sounds like you could have a clogged radiator, stuck thermostat, coolant leak or the radiator cooling fan is not working and there is an outside change you have a blown head gasket as well but to be sure lets run down these guides to help us pinpoint and fix the issue.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

and

https://youtu.be/5zpNjYmmiYY

and

https://www.2carpros.com/articles/car-is-leaking-coolant

and

https://www.2carpros.com/articles/replace-thermostat

Let us know what happens and please upload pictures or videos of the problem.
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Tuesday, June 1st, 2021 AT 6:28 PM (Merged)
Tiny
AMAZINBLAZIAN
  • MEMBER
  • 3 POSTS
I have only checked 3 plugs from each side but will go back and check each one before I do the compression test. Watched the 2 Car Pros video on this and didn't see any bubbles in the coolant or anything in the oil. Took the new thermostat back to O'Riley's and swapped it out. Just go back after a test drive and still getting message.
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Tuesday, June 1st, 2021 AT 6:28 PM (Merged)
Tiny
AMAZINBLAZIAN
  • MEMBER
  • 3 POSTS
Also, flushed the heater core and still no heat from the heater too. THank you for your quick response.
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Tuesday, June 1st, 2021 AT 6:28 PM (Merged)
Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
  • 2003 CHEVROLET SILVERADO
  • 185,000 MILES
I had a message on the display panel saying "ENGINE COOLANT HOT".
What should I do?
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Tuesday, June 1st, 2021 AT 6:28 PM (Merged)
Tiny
HMAC300
  • MECHANIC
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Do what I said in first reply checking compression isn't a real good test for head gasket leaks now adays
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Tuesday, June 1st, 2021 AT 6:28 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
I would start by changing the thermostat. It may be stuck shut and not allowing ant coolant to circulate.

https://www.2carpros.com/articles/replace-thermostat

https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars

I attached pictures and the procedure for you for the repair.

Roy
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Tuesday, June 1st, 2021 AT 6:28 PM (Merged)
Tiny
DANREID
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  • 2000 CHEVROLET SILVERADO
  • V8
  • 4WD
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I have a 2000 chevrolet 1500 and my check engine light is on. The code is reading coolant overtemp protection active. Will this cause my engine to run rough and misfire
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Tuesday, June 1st, 2021 AT 6:28 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
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It sounds like you have an engine that is overheating which can be caused by a blown head gasket. Here are some guides that will help us see what's going on.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

and

https://www.2carpros.com/articles/head-gasket-blown-test

Here are some notes from the book

Typically, a P1258 will cause the engine to run poorly as the PCM disables injectors at random in an effort to lower the engine temperature. Is the engine overheating, or is this code present at all times. If the coolant is being read as over 270 degrees(F), this engine protection mode is activated. If you have an overheat condition, that is what is causing the problem.

DTC P1258 Engine Coolant Overtemperature - Protection Mode Active

Circuit Description
In order to reduce the engine temperature the powertrain control module (PCM) has the ability to disable a number of fuel injectors during an engine over temperature condition. The PCM considers the engine over temperature whenever the engine coolant temperature (ECT) reaches a predetermined temperature. This DTC sets in order to show that the PCM detected an over temperature condition and that the system engaged the protection mode.

The PCM sends the instrument panel cluster (IPC) engine coolant temperature information via the Class 2 circuit. This information is used for controlling the coolant temperature gauge and for displaying a message when the coolant temperature is out of the normal operating range. The IPC displays a message when the engine coolant temperature is more than 121 C (250 F).

Conditions for Running the DTC
No active ECT DTCs

The engine is running.

Conditions for Setting the DTC
The engine coolant temperature is 132 C (270 F) or more.

The above conditions are present for more than 10 seconds.

Action Taken When the DTC Sets
The PCM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.

The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame and the Failure Records.

The message center displays a message.

The PCM alternately disables 4 injectors.

Conditions for Clearing the MIL/DTC
The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.

A last test failed, or current DTC, clears when the diagnostic runs and does not fail.

A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

Use a scan tool in order to clear the MIL and the DTC.

Diagnostic Aids
Important: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.

Important:

The PCM enables the engine coolant over temperature mode when coolant temperature exceeds 132 C (270 F). Engine damage still could occur if the customer operates the vehicle too long in an overheat condition. Ensure no engine mechanical conditions exists after the overheat condition is repaired.

If an overheating condition exists, repair the overheat condition and change the engine oil and filter.

Using the Freeze Frame and Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass or a fail. Operate the vehicle within the same Freeze Frame conditions, such as RPM, load, vehicle speed, temperature etc, that you observed. This will isolate when the DTC failed. For an intermittent condition, refer to Symptoms.

Test Description
The number below refers to the step number on the diagnostic table.

1.A cooling system that is not functioning properly enables the engine protection mode.

Please let us know what happens.

Cheers, Ken
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Tuesday, June 1st, 2021 AT 6:28 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

The code will not cause rough running at all. The rough running would be a result of overheating.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

As Ken posted, this could be a head gasket issue from the overheating.

I would start by doing a compression test to verify a head gasket You need 140-160 in each cylinder.

https://www.2carpros.com/articles/how-to-test-engine-compression

https://www.2carpros.com/articles/head-gasket-blown-test

If the gasket has failed, it would require removing the cylinder heads and having them checked for damage.

I attached a youtube video of the removal of the heads for you.

https://www.youtube.com/watch?v=n54vjm8CMNU

Roy
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Thursday, June 3rd, 2021 AT 2:31 AM

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