[Den49]

I followed the link and further followed the link to another thread in the Acadia Forum where a member took pictures of the intake valves on his SLT with 39K miles before and after cleaning with the CRC Cleaner.

The valves look quite clean with minimal deposits and the after pictures did not look appreciably better. Even the OP for the thread at the link provided (@Arminius who does not seem to be on this forum any longer) admitted he could not see the difference in the valves either in post #14.

Intake Valve Cleaning on 2018 SLT

Hey fellas... I'd like to clean the intake valves on my 2018 SLT with CRC GDI IVD intake valve cleaner. On my BMW I just take off the MAP sensor near the engine and spray quick burts directly into / onto the valves, but not sure where on the GM 3.6 engine where I could do that. Anyone got...

www.acadiaforum.net

I have not seen any pictures of intake valve carbon buildup in the LGX engine (the 3.6 in our XT5's) or the Corvette LT1 which have very effective PCV systems.

All of the carbon accumulation pictures are intake valves from years ago. If the existence of the problem is to be believed, we need up to date pictures.

CRC Cleaner and other consumer type spray can products that you can buy off the shelf at an auto parts store do not seem to be very effective. The only effective induction service I know of is the BG induction service using an induction tool and the BG GDI Air Intake & Valve Cleaner. I don't have any connection to or financial interest in BG. I have used their products and have seen them work as I reported in Post # 34 of the reference thread.

There was enough discussion about this subject in the above reference thread that I don't think is worth my time repeating. People can and will make their own judgements about this subject and what level of maintenance is necessary for their personal car. My purpose here in this forum is to get and provide information that will benefit me and others, not to engage in unending repetitive banter. That said, below is some useful information:

BG GDI Service - YouTube

 

[njacobsen]

There is no doubt BG GDI Air Intake & Valve Cleaner is effective when needed. However, there is no evidence the LGX engine used in several GM vehicles has an issue with intake valve carbon buildup. If it were an issue, pictures of the buildup on valves would be readily available.

 

[DanGilbertTX]

I don't know if these are part numbers or not, but this was the invoice for the work done on my XT5 replacing the thermostat.

 

[Cutlass]

The dealership sent me a list of items to address. Was wondering if anyone could say how important/necessary they are. Thanks in advance:

• Flush hydraulic brake system
  • 3 years or 30k miles
  • $157
• Decarb Engine MOC
  • 30k miles
  • $286
• Replace transmission fluid
  • 45k miles
  • $576

They also recommended some other stuff:

• Service battery
  • Which is funny because I replaced the battery less than 2000 miles ago
  • Also, what exactly do they do here? They charge $48 so that definitely isn't replacing the battery...
• Replace wiper blades
  • Did that this year too
  • $71 isn't too bad for parts and labor on it
• Replace engine and cabin air filters
  • $65 and $83 respectively
  • I have not done this, but am sure I can do these myself for much less.

Those services are just what the chart or computer spits out at them to sell to you. For the most part they are good services that won’t hurt and can only help. Are they needed immediately…no but whenever you’re ready to. And obviously if your battery and wipers are good, don’t do those. Let them know the status. Maybe they can update the computer with that info. If they can’t then those recommendations will keep coming up.
Glad you got the Tstat replacement!!

 

[Racoonlodge]

For anyone interested I too had the dreaded “action required steering assist is reduced " on the center display of this 2017 XT5 with 37k miles on it ...It had the same symptoms as some previous posters had mentioned ...Radiator fan running at its highest speed... Air conditioner stopped working... power steering seemed to be laboring or nonexistent and the temperature gauge needle showed no temperature...it read no temp the entire time the car was running. I tested the car with a code reader and it showed P0128

I decided to buy the coolant temperature sensor and the thermostat .. The plan was to replace the coolant temp sensor and see if that was all it needed. Best laid plans. Welp, I experienced so much difficulty in getting the sensor out all the way I surrendered and drove it to a shop…The shop used my parts as well as an intake manifold gasket, new antifreeze and charged me labor. Finished in a matter of hours with everything restored back to normal. The tech who did the work told me it was the thermostat.
View attachment 608119

Hello Jim
It's ironic you took a picture of your dash. I have a 2017 XT5 and every so often the "steering assist is reduced" flashes up on my dasdboard. Believe it or not I have one tire that has a slow leak and when I added air to 36 PSI, the message goes away! I can't see it being the cause, but with computers who knows! I see your pic has one tire low on air. I do not have any other issues happening with the assist message. Sounds crazy I know, but my message goes away! - Ray

 

[Cutlass]

Hello Jim
It's ironic you took a picture of your dash. I have a 2017 XT5 and every so often the "steering assist is reduced" flashes up on my dasdboard. Believe it or not I have one tire that has a slow leak and when I added air to 36 PSI, the message goes away! I can't see it being the cause, but with computers who knows! I see your pic has one tire low on air. I do not have any other issues happening with the assist message. Sounds crazy I know, but my message goes away! - Ray

All his tires are in the green. Yes one is lower, but still green. Don’t trick yourself…you likely need a t-stat replacement.

 

[Gina Lawrence]

Ok, got my vehicle back tonight and I am going to post exactly what is on my invoice for future reference on these forums. Hopefully what they did fixes this issue.

"Verified-scan, found U0140-Invalid Data From ECM & P0128 insufficient temp in ECM. Check coolant level-OK Check ECT reading in ECM data with GDS, Never goes above 185 deg, Check temp readings at T/STAT with inferred temp gun, TSTAT stuck open, Remove intake manifold, fuel rails & replace thermostat/water outlet pipe, Re-assemble, fill & bleed coolinig system, clear codes & test drive - OK...Replace water outlet/thermostat 4032830"

All of the above was under warranty with no deductible. Fingers crossed!

Was this covered under the regular warranty or the power train warranty? I have this happening and I am bringing it in to be diagnosed tomorrow. Vehicle is no longer under the regular 50,000 mile warranty but I see that it should be covered under power train warranty.

 

[Gina Lawrence]

Hello Jim
It's ironic you took a picture of your dash. I have a 2017 XT5 and every so often the "steering assist is reduced" flashes up on my dasdboard. Believe it or not I have one tire that has a slow leak and when I added air to 36 PSI, the message goes away! I can't see it being the cause, but with computers who knows! I see your pic has one tire low on air. I do not have any other issues happening with the assist message. Sounds crazy I know, but my message goes away! - Ray

I have that same problem! One tire is showing 29 lbs but doesn’t seem to be low. When I added air twice, it goes back down to 29 pounds the next day. And now the steering assist message has come on with the temperature gauge reading cold and the AC not blowing cold air.

 

[njacobsen]

I have that same problem! One tire is showing 29 lbs but doesn’t seem to be low. When I added air twice, it goes back down to 29 pounds the next day. And now the steering assist message has come on with the temperature gauge reading cold and the AC not blowing cold air.

Sounds like you have two problems. Tires should be inflated to 36lbs as indicated on the placard in the driver door frame. If you inflated to 36 and was down to 29 the next day, that tire needs to be repaired because it either has a puncture or rim leak.

The other problem is symptomatic of a cooling system issue, frequently a thermostat that is stuck open.

 

[abashrawi]

I have periodically had this message pop up on my message center dashboard. I think that it is related to weather/rain/carwash ( I think I had seen this on the forum last year).
I also occasionally have the check engine light come on also. Example: last Tuesday the Steering Assist message came on, then after several stops and starts the check engine light came on and both stayed until Friday. Then they both disappeared(turned off). Saturday evening (yes, it rained) the Steering Assist Reduced message returned. I have an appointment scheduled for Monday, but would like to go to it armed with more knowledge than I currently have. All information would be appreciated. Last January I had several messages constantly popping up on the dashboard and the dealer did a software update which seemed to help.

I had this message appear twice. One time it was happening occasionally when the car was coming of an auto stop start event and it was identified to be a faulty battery. Another time it showed up together with the fan spinning at full speed all the time, and was caused by a faulty thermostat.

 

[EsthersDoll]

I'm having this same problem. I took my car to the dealer on Monday, they used over a 1/4 tank of gas while it was there and then told me it was fixed by reseting my system. They said when AAA changed the battery a few months ago it caused a chain reaction of errors that culminated into the Steering Assist Reduced Drive With Care. Well, guess what, the error returned tonight and I think their telling me the need to reset the system is a load of hooey.

I specifically listed the Service Bulletin listed in this video, and referenced in this thread, as the possible issue when I called them and when I dropped it off to them.

I'll be calling them again first thing tomorrow morning to get this fixed. My Powertrain Warranty is still active and this error should be covered from what I have gathered.

 

[EsthersDoll]

I'm having this same problem.

Update: The dealer took my car and gave me a loaner. They said the part they need to fix the issue is at least two weeks out.

 

[Cutlass]

Not every tech in every dealer is great or equal. Everyone with a new car under warranty runs the risk of getting a not experienced tech or service writer. But with knowledge from this group, it can be easy

 

[58c]

With the thermostat stuck open, the engine not only was not reaching operating temperature at only 185 degrees, but it was always taking an extraordinarily long time to get to even that temperature. All of the technology designed and programmed into the engines of these vehicles is very dependent on reaching a normal operating temperature in a very short amount of time.

 

[58c]

I’m new to the forum however I’m experiencing the steering assist diminished message and also another symptom the temp gauge stays on the cold mark and then suddenly pops up to normal.
I have done some research and by the way I have a strong mechanical background. There is a Service Bulletin 17-NA-158that came out in May 2017 that addresses this issue. The thermostat or ( water outlet as GM calls it) is sending false signal to the ECM. The electric power steering unit uses the temp signal to determine how much power it uses according to how cold the grease is in the unit. Therefore if the grease is cold and the power is reduced the error message and the temp gauge stuck in the cold position. If you check for a code in the computer it should show P0128 Thermostat temp error. Dealer should replace the water outlet under warranty if they have it or can get.

 

[yodamaster]

I’m new to the forum however I’m experiencing the steering assist diminished message and also another symptom the temp gauge stays on the cold mark and then suddenly pops up to normal.
I have done some research and by the way I have a strong mechanical background. There is a Service Bulletin 17-NA-158that came out in May 2017 that addresses this issue. The thermostat or ( water outlet as GM calls it) is sending false signal to the ECM. The electric power steering unit uses the temp signal to determine how much power it uses according to how cold the grease is in the unit. Therefore if the grease is cold and the power is reduced the error message and the temp gauge stuck in the cold position. If you check for a code in the computer it should show P0128 Thermostat temp error. Dealer should replace the water outlet under warranty if they have it or can get.

I got this error yesterday and the AC stopped working. It just went away in its own but I’m going to make an appointment with the Cadillac dealer for this TSB to be done under warranty and will ask them to order the part ahead of time. I also watched that video.

 

[njacobsen]

I got this error yesterday and the AC stopped working. It just went away in its own but I’m going to make an appointment with the Cadillac dealer for this TSB to be done under warranty and will ask them to order the part ahead of time. I also watched that video.

Good luck getting them to order the parts ahead of time.

 

[yodamaster]

Good luck getting them to order the parts ahead of time.

Thanks. I’ll let you know.

 

[Racoonlodge]

Well, well...just passed 49K and I got the dreaded "steering assist is reduced" along with check engine light and they both ain't going away. I called the dealer and have an appointment in a week. I ran diagnostics and yes, it's P0128. Will let you know what happens

 

[Racoonlodge]

Took my XT5 with the "steering assist is reduced" to the dealer and this was the verbiage of the technician who worked on the problem....

They saw the P0128 code and verified the sensor was at fault.
Well, it just took one day and the issue came back on my dash, "steering assist is reduced"!!
have another appointment next week and I will tell them what is really the issue.