ENGINE HOT - A/C OFF message on DIC

[MRICO]

This msg has been coming on when I don't let my car "warm-up" prior to driving. Once I disconnect the battery to make msg "disappear", this msg won't come back on until I fail to warm up the car prior to driving. Again, if I warm up the car (I literally have to just let it idle for 1-3 minutes and the temp gauge doesn't even have to move) prior to driving, I never get the ENGINE HOT - A/C OFF message. On another post someone mentioned a thermostat problem but I don't think that's it...im thinking its some other type of sensor. Any ideas? Also, once this code has been activated, if I don't reset it (disconnecting/reconnecting the battery), when I start the engine even after a few days of not driving, the radiator fan immediately comes on and stays on because its "thinking" its hot.

 

[cubby558]

Disconnecting the battery does not eliminate a code which has been set. It merely resets and will reappear if the same situation occurs. A Tech II will tell you what code set and you can start to evaluate your problem.

This msg has been coming on when I don't let my car "warm-up" prior to driving. Once I disconnect the battery to make msg "disappear", this msg won't come back on until I fail to warm up the car prior to driving. Again, if I warm up the car (I literally have to just let it idle for 1-3 minutes and the temp gauge doesn't even have to move) prior to driving, I never get the ENGINE HOT - A/C OFF message. On another post someone mentioned a thermostat problem but I don't think that's it...im thinking its some other type of sensor. Any ideas? Also, once this code has been activated, if I don't reset it (disconnecting/reconnecting the battery), when I start the engine even after a few days of not driving, the radiator fan immediately comes on and stays on because its "thinking" its hot.

 

[Rule62]

This msg has been coming on when I don't let my car "warm-up" prior to driving. Once I disconnect the battery to make msg "disappear", this msg won't come back on until I fail to warm up the car prior to driving. Again, if I warm up the car (I literally have to just let it idle for 1-3 minutes and the temp gauge doesn't even have to move) prior to driving, I never get the ENGINE HOT - A/C OFF message. On another post someone mentioned a thermostat problem but I don't think that's it...im thinking its some other type of sensor. Any ideas? Also, once this code has been activated, if I don't reset it (disconnecting/reconnecting the battery), when I start the engine even after a few days of not driving, the radiator fan immediately comes on and stays on because its "thinking" its hot.

I had this problem and replaced my temperature sensor and pigtail. It happened again and my mechanic said the thermostat is the likely culprit. We replaced that and have not had a problem since.


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[MRICO]

Thanks for that Rule62

I had this problem and replaced my temperature sensor and pigtail. It happened again and my mechanic said the thermostat is the likely culprit. We replaced that and have not had a problem since.


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I'm by no means a mechanic, but that was the answer I was looking for. Hopefully its easy and I can do myself...

I recently took it to the dealer (Arrowhead Cadillac) where they replaced a leaking water pump, you would think they would have replaced the thermostat while they were in there...that's why I like the idea of the sensor and pigtail.

Thanks Again

 

[Rule62]

I'm by no means a mechanic, but that was the answer I was looking for. Hopefully its easy and I can do myself...

I recently took it to the dealer (Arrowhead Cadillac) where they replaced a leaking water pump, you would think they would have replaced the thermostat while they were in there...that's why I like the idea of the sensor and pigtail.

Thanks Again

Geez...I thought for sure a new water pump would have meant a new thermostat. Unbelievable!


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[thumper]

I had this problem and replaced my temperature sensor and pigtail. It happened again and my mechanic said the thermostat is the likely culprit. We replaced that and have not had a problem since.


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Didn't replace sensor. Just thermostat. That fixed it.

 

[xlrlist01]

Didn't replace sensor. Just thermostat. That fixed it.

It might be useful to understand what is going on here.

The "Engine hot" message does not mean that the engine is hot, it means that the engine might be hot. This situation arises because the engine management computer can't work out what is wrong. What it 'knows' is that the engine isn't being reported as hot enough after a period of driving (it isn't warming up fast enough). The two major causes of this are defective sensor and defective (open too early) thermostat. The more serious condition is failed sensor and the risk of an over-heated engine, hence the warning message (and the computer will take other steps to reduce power output so as to limit damage).

By running the engine without driving the car, there is no airflow over the radiator, so the stuck open thermostat has a much reduced effect on the delayed warm-up, sufficient for the engine management computer to detect a 'sufficiently warm engine' in the time period allocated and the fault does not get set.

HTHs.

 

[Rule62]

It might be useful to understand what is going on here.

The "Engine hot" message does not mean that the engine is hot, it means that the engine might be hot. This situation arises because the engine management computer can't work out what is wrong. What it 'knows' is that the engine isn't being reported as hot enough after a period of driving (it isn't warming up fast enough). The two major causes of this are defective sensor and defective (open too early) thermostat. The more serious condition is failed sensor and the risk of an over-heated engine, hence the warning message (and the computer will take other steps to reduce power output so as to limit damage).

By running the engine without driving the car, there is no airflow over the radiator, so the stuck open thermostat has a much reduced effect on the delayed warm-up, sufficient for the engine management computer to detect a 'sufficiently warm engine' in the time period allocated and the fault does not get set.

HTHs.

This is essentially what my mechanic told me (however "less-fancy" it may have been). My V is 10 years old, and under a $0 deductible warranty for another 2 years or 40k. So my motto is " replace, replace, replace"!!! Hence the new temp sensor and thermostat. [emoji6]


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[PTpro]

This is essentially what my mechanic told me (however "less-fancy" it may have been). My V is 10 years old, and under a $0 deductible warranty for another 2 years or 40k. So my motto is " replace, replace, replace"!!! Hence the new temp sensor and thermostat. [emoji6]


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My 2006 XLR-V has been doing that once every 6 to 9 months for the last 8 years and I have not replaced anything. Three different Cadillac dealership experts said they could not pin point the issue and to wait until something has a permanent fail. After 5 or 6 times of using the car from a cold start the message just disappears on its own and everything goes back to normal again for 6 to 9 months, or when I'm impatient, I have my mechanic run diagnostics to find nothing wrong and resets the code and again I'm good for another 6 to 9 months, sometimes over a year! Go figure, but replacing expensive parts and having the issue go unresolved is even more frustrating and frustrating. Now as my V has over 72000 miles on it, I have my mechanic run a diagnostic each time hoping a definitive issue will be made apparent. My mechanic suspects the temperature sensor loses it mind occasionally and needs replacement, but because the location of that sensor is at an extremely hard to get at location at the back of the engine, he said the labor costs to replace it could be between 6 and 8 hours. That's a lot of money for an occasional sensor mind loss. I will have it done if and when it completely loses its mind.

 

[MRICO]

My 2006 XLR-V has been doing that once every 6 to 9 months for the last 8 years and I have not replaced anything. Three different Cadillac dealership experts said they could not pin point the issue and to wait until something has a permanent fail. After 5 or 6 times of using the car from a cold start the message just disappears on its own and everything goes back to normal again for 6 to 9 months, or when I'm impatient, I have my mechanic run diagnostics to find nothing wrong and resets the code and again I'm good for another 6 to 9 months, sometimes over a year! Go figure, but replacing expensive parts and having the issue go unresolved is even more frustrating and frustrating. Now as my V has over 72000 miles on it, I have my mechanic run a diagnostic each time hoping a definitive issue will be made apparent. My mechanic suspects the temperature sensor loses it mind occasionally and needs replacement, but because the location of that sensor is at an extremely hard to get at location at the back of the engine, he said the labor costs to replace it could be between 6 and 8 hours. That's a lot of money for an occasional sensor mind loss. I will have it done if and when it completely loses its mind.

So sadly funny. I really like my car buts it's obvious an electrical mess! Now Everytime I shut down my car...BOTH rear view mirrors go down almost showing the ground...WHAT THE HECK?
I hope there's no ejection seat button I'm missing (or its created)!

 

[onalaska]

Try replacing the thermostat first. It's and easy job, no expensive parts, and it fixed mine when I had the exact same message on the DIC.

 

[PTpro]

Try replacing the thermostat first. It's and easy job, no expensive parts, and it fixed mine when I had the exact same message on the DIC.

As I mentioned in my post, it can happen in 6 months to over a year before it happens again. How long ago did you have your thermostat replaced? Give it more time, it may perhaps happen again!!!

 

[Rule62]

As I mentioned in my post, it can happen in 6 months to over a year before it happens again. How long ago did you have your thermostat replaced? Give it more time, it may perhaps happen again!!!

It happened to me three times in as many months. The first two times it went away within a day or so. The last time it was still on almost a week later when I brought it into the mechanic. I should also mention that the temperature gauge stops working in conjunction with the DIC message.

Given my generous warranty provisions, it would be foolish to just ignore it. Doesn't cost me a dime!


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[PTpro]

It happened to me three times in as many months. The first two times it went away within a day or so. The last time it was still on almost a week later when I brought it into the mechanic. I should also mention that the temperature gauge stops working in conjunction with the DIC message.

Given my generous warranty provisions, it would be foolish to just ignore it. Doesn't cost me a dime!


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What did you do to end up fixing the issue? How long has this issue not occurred since the last time you had if supposedly fixed?

 

[Rule62]

What did you do to end up fixing the issue? How long has this issue not occurred since the last time you had if supposedly fixed?

Replaced thermostat. Hasn't happened since and it's been 3 months / 450 miles or so.


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[PTpro]

Replaced thermostat. Hasn't happened since and it's been 3 months / 450 miles or so.


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The proof to me will be after having a year of so of no issues. Please do not take offence to my comment, I say a year or more because mine can disappear that long before occurring again. God willing, if we remember our chatting, we will make contact again next year at this time to determine your solution truly valid.

 

[Rule62]

The proof to me will be after having a year of so of no issues. Please do not take offence to my comment, I say a year or more because mine can disappear that long before occurring again. God willing, if we remember our chatting, we will make contact again next year at this time to determine your solution truly valid.

Ok then.


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[onalaska]

Engine Hot - A/C off DIC message

As I mentioned in my post, it can happen in 6 months to over a year before it happens again. How long ago did you have your thermostat replaced? Give it more time, it may perhaps happen again!!!

I replaced the thermostat on 12/18/13 at 69,501 miles because of the message on the DIC. I now have 80,310 miles and have never had the problem again over three years later.

Just got back from a 2,500 mile trip with no problem. Still impressed on how comfortable this car is on long trips.

I'm sure in your case if you don't replace it it may happen again.

 

[PTpro]

I replaced the thermostat on 12/18/13 at 69,501 miles because of the message on the DIC. I now have 80,310 miles and have never had the problem again over three years later.

Just got back from a 2,500 mile trip with no problem. Still impressed on how comfortable this car is on long trips.

I'm sure in your case if you don't replace it it may happen again.

Ok, THANK YOU VERY MUCH!!! Now that's what I wanted to hear. These intermittent issues are extremely difficult to pin point the cause, especially this one because the diagnostic computer, at the time when actually used to determine the issue, does not indicate anything causing the issue. I am now thinking the thermostat must be intermittently malfunctioning and that is why the diagnostic cannot catch it after it trips the sensor. It sure is nice having a forum like this in order to remedy quirky issues. Thanks again for you update!

 

[xlrlist01]

Ok, THANK YOU VERY MUCH!!! Now that's what I wanted to hear. These intermittent issues are extremely difficult to pin point the cause, especially this one because the diagnostic computer, at the time when actually used to determine the issue, does not indicate anything causing the issue. I am now thinking the thermostat must be intermittently malfunctioning and that is why the diagnostic cannot catch it after it trips the sensor. It sure is nice having a forum like this in order to remedy quirky issues. Thanks again for you update!

It is also possible that you have the wrong thermostat fitted and it opens too soon. Some owners like to run their engines with a low opening temperature thermostat, I don't know if you know the full service history of your XLR. A technician should measure the temperature of the coolant when diagnosing that error message. Measuring the rate of warm-up can also be a strong pointer to a thermostat problem.