19 Acadia "Steering Assist Reduced" P0128 Thermostat code.

Customer states steering assist is reduced messages displaying on driver information center.
Codes P0128 U0415 stored. Applicable bulletin states to resolve P0128 first.
Thermostat quick test with two methods. Thermostat housing replacement tips. Confirmation after repair.
#cars #mechanic #automotive #knowledge #tipsandtricks #engine

[@advancedleveldiagnostics]

Wow, that job looked like a pain! Thanks for sharing!

[@DadsGarageDiagnosticSpecialist]

It wasn't too bad. I've done worse. Thanks for watching and commenting!

[@renec0327]

I seen a video from other guy and he made it so easy pulling up the thermostat without taking any part

[@DadsGarageDiagnosticSpecialist]

Some are easier than others I’ve noticed. Thanks for commenting.

[@bigperm079]

My mother just purchased 2019 gmc acadia & it's not even a week old & this problem has occurred 🤦‍♂️. I'm pretty sure warranties will cover but I feel like the dealership had to see this issue 🤷‍♂️ Anyways thanks for this awesome video 👍👍

[@DadsGarageDiagnosticSpecialist]

Thank you for watching! Hopefully it was just a misunderstanding, and they overlooked something. I doubt they did it on purpose, give them a chance to fix it.

[@torinpickford152]

Yea I just purchased a 2020 acadia last april. Same issue just occurred should be covered under warranty. The video is super helpful

[@DadsGarageDiagnosticSpecialist]

@@torinpickford152 i’m glad you found it helpful!

[@tyking6994]

Just got one 30k miles having issue now

[@bigperm079]

@@torinpickford152 yeah it was covered but such a inconvenience to have for a newly purchased vehicle 🤷‍♂️

[@dull_boy_274]

do you have a part number for the bleed pipe o-rings? I can't find them anywhere

[@DadsGarageDiagnosticSpecialist]

12648547 Thanks.

[@thomaszimmerman8566]

just replaced the ect sensor and thermostat on my 2018 3.6 canyon and my truck still will not get up to operating temp any ideas?

[@DadsGarageDiagnosticSpecialist]

Did you use OEM parts? What temperature does your gauge display? Your temperature gauge should read approx. 190F-210F at normal operating temperature and should stay there while driving. Thanks.

[@Peter_Riis_DK]

What about the shuddering torque converter - any result on that?

[@DadsGarageDiagnosticSpecialist]

Customer declined to service the transmission fluid due to his budget. This was sad story walk-in two of three that day…. Was able to diagnose, repair, and return the vehicle to them in the same day. Thanks.

[@Peter_Riis_DK]

@@DadsGarageDiagnosticSpecialist Good to hear, well done. Makes me wish I had you in my neighborhood. It's sad times we live in though; many have a hard time making ends meet.

[@chandlerlofton6536]

I haven’t seen an air ratchet in years!

[@DadsGarageDiagnosticSpecialist]

That’s funny! You can tell the era that I come from… back when I was buying tools electric was still big and clunky with no battery life. Hard to beat air tools sometimes…. Endless power. Thanks.

[@cameronbeard9533]

This is likely a dumb question. What’s the downside to buying an OD2 scanner and just clearing the code since this issue is more of an inaccurate “glitch”??

[@DadsGarageDiagnosticSpecialist]

That really depends on what code is setting and just how frequently the code will set. For example this vehicle had a P0128 code, every time you cold start the engine the computer starts a timer…if the coolant temperature doesn’t warm up fast enough the computer assumes there is a problem with the thermostat…. Usually the self test needs to fail a few times before the light will come back on. The steering being affected is something known as “failure-effects-management”…. The PCM and other modules are programmed “when this code fails the test this many times, do this.” The vehicle in this video definitely needed a thermostat, but I’ve also seen the P0128 code be reset and then not come back for 6 months until the cold of winter because the thermostat hadn’t failed bad enough yet. On any other car I would say it’s probably going to be fine if the thermostat is stuck open because the risk of engine damage is low…. Except this vehicle seems to affect the steering in an unpredictable way so I don’t like the idea of erasing the code on this one. If you have that $25 code reader you can diagnose the thermostat in the same way shown in this video. Thanks.

[@DJT_2024]

$14.00 amazon problem fixed

[@christiandavis3910]

Just had this happen on my wife’s Acadia tonight. Riddle me this, why does the AC also not blow cold when this happens?

[@DadsGarageDiagnosticSpecialist]

If the ECM can’t trust the coolant temperature sensor it will disable A/C operation when code P0128 sets. Because there is only one coolant temperature sensor the ECM has no way of knowing whether the coolant temperature is accurate or not so it assumes the sensor is reading low and the engine could overheat. It’s called “failure-effects-management”… something I’d like to do a future video on. Thanks.

[@christiandavis3910]

@@DadsGarageDiagnosticSpecialist thanks for that detailed response. My local dealer is taking care of this issue for my wife under powertrain warranty. Blows my damn mind that a thermostat is toast after 55000 miles. I’ve got a 17 6.7 psd with 361k and haven’t had to change anything like that.

[@bigperm079]

@@christiandavis3910 same with my mother's Acadi, she just got hers not even 7 days old & it's having this problem 🤦‍♂️

[@christiandavis3910]

@@bigperm079 Jesus.

[@goldenautorepair9930]

yes

[@bassbuggy101]

Getting this code on my 2018.. but if I clear the code it will stay off for a week or 2 and run completely normal! Is it still thermostat or just the coolant temp sensor? Thanks

[@DadsGarageDiagnosticSpecialist]

I had a 2017 Acadia with this code… I erased it and it didn’t come back for about six months until the cold season hit. A faulty thermostat is more likely… A current temperature sensor is also a possibility Thanks.

[@samanthafrancisco17]

@@DadsGarageDiagnosticSpecialistMy 2017 Acadia only likes to throw this code when it gets warm. Going to see if this is something my husband can handle.

[@DadsGarageDiagnosticSpecialist]

@samanthafrancisco17 I just replaced another one yesterday, it wasn’t that bad. I followed the same process in the video. Thanks.

[@chrisliang8016]

Hi I replaced the thermostat and the sensor on my 17 Acadia, and the fan is still not moving. Any ideas why? Thanks

[@DadsGarageDiagnosticSpecialist]

The cooling fan will only turn on as needed. If you turn the AC on maximum, the fan should run on high at some point. Thanks.

[@chrisliang8016]

@@DadsGarageDiagnosticSpecialist thanks a lot for your reply. I was told that the fan wouldn’t run even at 107 celsius. Does this mean I should look into replacing it?

[@DadsGarageDiagnosticSpecialist]

@@chrisliang8016 no. It would need to be tested.

[@chrisliang8016]

@@DadsGarageDiagnosticSpecialist thanks a lot!

[@DadsGarageDiagnosticSpecialist]

@chrisliang8016 you are welcome.

[@cz6791]

Wow thats absolutely absurd for a thermostat replacement. Can you tell me approximately what that job costs to have done?

[@DadsGarageDiagnosticSpecialist]

This isn’t too bad compared to some other jobs. It would be approximately $500 or so to replace the thermostat using the shown procedure. It’s more if replacing the whole cross-over pipe, but that is not often needed. Thanks.

[@cz6791]

Thank you. I appreciate the info

[@jeremiahnichols8272]

Engineers don't think, "Hmmm is this going to be insanely difficult to repair?" The more and more I look at this engine the more I'm thinking to stay away from this thing completely.

[@DadsGarageDiagnosticSpecialist]

I don’t blame them because I know that there is a group of executives that sit around the table and make all the dumb decisions for them. This engine actually isn’t that bad to work on. The early version of this engine was kind of a piece of crap with timing chain issues, but I think that they have that figured out. Thanks.

[@MarioFlores-hi1do]

Hello, excellent video, can you tell me where I can buy it or the part number please?

[@DadsGarageDiagnosticSpecialist]

I would advise getting the part from the dealer. Then you know its a genuine part and not a cheap copy. Thank you very much!

[@Bullwinkle056]

Why in the world would they bury the thermostat so deep in the engine??? I see that GM V8's still have it in a reasonably easy spot in the upper radiator hose.

[@DadsGarageDiagnosticSpecialist]

I’ve seen worse designs. I can’t explain why they do what they do other than space and packaging of the engine in the vehicle. Thanks for commenting.

[@thaiebony]

I was just quoted $2300 from GMC for my 2019 Acadia. 🥴

[@DadsGarageDiagnosticSpecialist]

That seems a little high unless they’re replacing the injectors at the same time or something. Thanks.

[@nicksteele9732]

They told me tge same thing to replace tge rack and pinion system.

[@terrybryant]

GM does it again. Can anyone remember when changing a thermostat on ANY vehicle took about 20 minutes?

[@DadsGarageDiagnosticSpecialist]

I member! Thanks

[@ericl8593]

So u didn’t really have to remove the motor mount ??

[@DadsGarageDiagnosticSpecialist]

Probably not, but it sure does make it a lot easier to scrape the surfaces, clean and prepare for reassembly. Thanks.

[@ericl8593]

@@DadsGarageDiagnosticSpecialist I believe that . Another question I have now is these newer gms have full electric steering . I’m not fully understanding why coolant temps have anything to do with the steering ? I know there’s grease in the gear box that when cold gets thicker and the steering module reports back to the ecu and that’s why the code gets popped but how it physically measuring the coolant temp ?

[@DadsGarageDiagnosticSpecialist]

@@ericl8593 the coolant temperature is communicated from the engine control module to the power steering control module. If the ECM flags that there is a potential cooling system fault, the power steering control module assumes that the temperature data cannot be trusted and goes into fault mode. They do this simply because the steering gear is close to the engine and they assume if the engine is overheating, or potentially running too cold, the viscosity of the steering gear grease could be affected.

[@ericl8593]

@@DadsGarageDiagnosticSpecialist ok I figured if it wasn’t directly tied into the coolant flow that it had to be them banking on engine temps to warm the grease . It just seems like a odd way for 2 systems to communicate

[@DadsGarageDiagnosticSpecialist]

@ericl8593 yes it is a little bit strange, but that is the way they built it lol

[@JohnsonEJ]

I was going to do the thermostat myself but that looks like a pain in the ass lol I think I'll just drop it off next week at gmc

[@DadsGarageDiagnosticSpecialist]

It sure can be a pain sometimes. Thank you for commenting.

[@cesarmejinez5273]

How much did they charge you?

[@golf25radioman]

Not an easy job anymore to replace a thermostat! Wow. The more they cram components into these engine compartments the more difficult it is to service them.

[@DadsGarageDiagnosticSpecialist]

That’s right. Some engines also require the GDI fuel injectors and fuel rails to be removed which requires more tools and parts. Thanks for commenting.

[@nicksteele9732]

The dealership is telling me i need to fix the whole rack and pinion system

[@DadsGarageDiagnosticSpecialist]

Depends what they found when they diagnosed it. My 2017 Acadia did this one time ever. I cleared the codes and drove it for another year or so before getting rid of it. If the fault comes back immediately after clearing the codes then there is probably something other than a thermostat causing it. Thanks.

[@christinaperez6024]

I was just quoted 1200$

[@DadsGarageDiagnosticSpecialist]

That is fairly accurate if they plan to remove the intake manifold and remove the fuel injectors and remove the entire pipe, etc. The updated procedure is to do it the way that I show in this video… And re-use the pipe without taking the injectors out. Thanks.