# code 4 for the third time in less then 2 years... what to replace this time...



## j2daff (Dec 17, 2014)

I had this lovely code 4 with engine light starting in 2013 I believe. Had the thermostat replaced and then the error popped up again in March of 2014 along with the cooling fan running on high and constantly when the error was up(not sure if i had the fan issue in 2013 but i think so) so the dealer replaced the ECT sensor (not sure which one). 

Now it is happening all over again. I had moved about an hour from my previous house so took it to a new dealer. Explained the history and that the temp gauge would sway almost with the momentum of the car before the Code 4 popped up and shut it off. They charged me for diagnosing it said everything was fine the engine was just miss-reading the coolant temp. and the comp. needed to be flashed(updated) so the charged me for that too. They told me maybe a rat or something chewed a wire but they could not see anything, cleared the codes and said everything was fine now. I left quite frustrated knowing it would be back in a few days and yep it was two days later... right on cue... thanks a bunch...lol

if all i wanted was a few days with out the fan noise i would have just cleared the codes myself... heck i did it in March...

At this point i am quite frustrated seeing it is likely most of these repairs, diagnostics and replacements are not covered under the power-train warranty and they just will not stop repeating themselves. I was thinking the diesel cruze looked nice and might be a good upgrade at some point but this has soured me to the point i do not think i could ever buy another cruze and maybe even steer me away from GM.... maybe I am just frustrated...


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## spacedout (Dec 7, 2010)

I would contact customer service, no way you should be paying for so called repairs that don't actually address the problem. Especially with an ongoing issue.


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## Gus_Mahn (Aug 16, 2011)

What is code4? P0004 is an unused code.


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## Chevy Customer Care (Oct 29, 2011)

j2daff said:


> I had this lovely code 4 with engine light starting in 2013 I believe. Had the thermostat replaced and then the error popped up again in March of 2014 along with the cooling fan running on high and constantly when the error was up(not sure if i had the fan issue in 2013 but i think so) so the dealer replaced the ECT sensor (not sure which one).
> 
> Now it is happening all over again. I had moved about an hour from my previous house so took it to a new dealer. Explained the history and that the temp gauge would sway almost with the momentum of the car before the Code 4 popped up and shut it off. They charged me for diagnosing it said everything was fine the engine was just miss-reading the coolant temp. and the comp. needed to be flashed(updated) so the charged me for that too. They told me maybe a rat or something chewed a wire but they could not see anything, cleared the codes and said everything was fine now. I left quite frustrated knowing it would be back in a few days and yep it was two days later... right on cue... thanks a bunch...lol
> 
> ...


Hi there,

So sorry for this! I can only imagine your frustrations, and if you need any additional assistance, please feel free to send me a private message. Be sure to include your VIN, current mileage, contact information and preferred dealership. I would be happy to contact them on your behalf.

Patsy G
Chevrolet Customer Care


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## j2daff (Dec 17, 2014)

Chevy Customer Care said:


> Hi there,
> 
> So sorry for this! I can only imagine your frustrations, and if you need any additional assistance, please feel free to send me a private message. Be sure to include your VIN, current mileage, contact information and preferred dealership. I would be happy to contact them on your behalf.
> 
> ...


PM d ... thank you for offering assistance


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## j2daff (Dec 17, 2014)

Gus_Mahn said:


> What is code4? P0004 is an unused code.


it is code 4 displaying on the dash (usually with a check engine light as well) ... i believe it refers to high coolant or engine temp. and thus turns the fan on for cooling. From what i have seen on-line and with my car there are underlying codes such as P0119 which I have seen every time I believe although with others, I have seem 1 other for sure maybe two, i did not run the codes myself this time. It also locks the AC off for safety reasons. I believe GM actually put out a service bulletin on this issue with the following steps.


Step 1 - Verify software revision in engine computer for engine coolant temperature control, flash to latest revision if not. 


Step 2 - If step 1 doesn't resolve problem, verify thermostat value operation. If incorrect, replace. 


Step 3 - If step 2 doesn't resolve problem, monitor and verify engine temperature sensor. Replace if outside of allowable tolerance range. 


Step 4 - If step 3 doesn't work, evaluate entire cooling system, radiator, water pump, etc.


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## rcclockman (Jan 16, 2012)

Why pay to fix sensors that protect the engine from failure on your dime? Just drive it till it blows and let Gm pay for it..


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## j2daff (Dec 17, 2014)

rcclockman said:


> Why pay to fix sensors that protect the engine from failure on your dime? Just drive it till it blows and let Gm pay for it..


as much as i laughed when i read this.... to apply some logic to it to answer the question... it effect gas mileage and is annoyingly loud


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## rgpg_99 (Jan 8, 2012)

j2daff said:


> it is code 4 displaying on the dash (usually with a check engine light as well) ... I believe GM actually put out a service bulletin on this issue with the following steps.
> 
> Step 1 - Verify software revision in engine computer for engine coolant temperature control, flash to latest revision if not.
> 
> ...


Do you happen to know that service bulletin number? 

Each time I mention to my dealer the new information shared on the forum, the general answer is "If it's not on a service bulletin, it's not something we can really consider". I tell the service person there may be plenty of relevant information out there that may not have made it into a service bulletin, but that doesn't fly with him.


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## j2daff (Dec 17, 2014)

*j2daff*

Anyway, no I do not no the bulletin number (it may have been a service procedure in hindsight) as I pulled that off another post somewhere and looking back without the frustration it's might just be a common issue with these cars and the dealers do have there service procedure on it. Some thing I did find out though and I guess I should feel silly about it in hindsight, but when they are replacing the thermostat and sensors they do not change the coolant. I had it done instead of replacing a sensor for the third time, reset the code my self and my issue never came back... I hadn't thought of changing the coolant as there first dealership that replaced 2 thermostats and both sensors once told me they were changing the coolant each time. Turns out there is no chance they were as it's been years. Sad I paid for 2 sensors and a thermostat out of warranty before realizing the dealership was screwing me over.


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## j2daff (Dec 17, 2014)

oh and also consider this, dealerships make more money servicing vehicles than they do selling them. What does that tell you about what a successful business model would likely include? The guy at the counter wants you to feel you were service well, politely but at the end of the day he doesn't care if you spend $50 or $1000 as long as next time you will come back to them. If you are having this issue (also my fan was running on high most of the time too) then start by flushing your coolant then I'd recommend the thermostat, then if it still continues to happen maybe the sensors one at a time... remember to make sure the codes are cleared each time or it may not go away even if the issue is fixed.


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## Chevy2012 (Nov 20, 2019)

I’m having same issues. My fan turned off after replacing the radiator and coolent sensors but my code came back so I replaced the thermostat. Guess what my code came back. I don’t know what to do now. Also my code is a permanent code now. So I don’t know what that means or how to fix it. Any ideas on what to do next? Also I made a discussion on my profile about other issues if anyone’s wants to take a guess at all that...


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## mado (Jan 22, 2021)

The same story for me. I have a chevy 2011. I replaced the thermostat more than 4 times.


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