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2020 Sierra - Various Mechanical/electrical/digital problems (Mirror vibe, locks, navi, seats, rear park assist)


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Hi All,

 

2020 GMC Sierra 1500 AT4 5.3L with “premium package” (Sun roof, wireless charger, 20” rims etc).

 

I’ve been running into some electrical issues. My dealer is a 45min drive away, and I’ve been there several times with little result. Regularly it seems like I know more about my truck than they do, which is not uncommon with most dealerships I’ve dealt with. To be fair, I do research on my specific model, and they have to have a bit of knowledge on all GMC, Chevy, etc. I’ve been to the dealership 4-5 times in 6 weeks.

 

1. Seat memory (clarification):

- Do the seats return to memory of the Key fob (1 &2) when the door is unlocked and opened? Or only at start? Every vehicle I’ve had/used (Acura, Honda, Nissan, subaru, Audi, VW, etc) always returned to position from my wife’s spot to my own at door open. (I’ve looked through the menus (DIC, main screen), haven’t found a setting to change between door open or driver start). *Dealer just printed out a guide on how to set the seats. It SEEMS like only on ignition on - this may be due to the “exit memory” but even turned off there is no Change.

SOLVED: Seat adjustment only occurs at ignition start. Not at door unlock or door open. Setting door exit position to my (Driver 1) seat arrangement means the seat will be ready for me after my wife steps out.

 

2. Navigation SD card.

- I turn the truck on, it tells me that “once the as card is initialized with the vehicle, it cannot be changed” - press ok. Except this pops up each and every time I start the truck. Just initialize already!!? It won’t progress past this until I press ok. Added to that, the navi will randomly tell me the SD card as been removed (when it has not been touched) and won’t work again until I restart the truck. Is this an issue with all 2020 Navi’s?

* Dealer claims they “think” they tried swapping out the memory card and no change. I asked again later at a subsequent visit and they said they would have to order a new one in to do that (Ok, please do that?). Then they said GMC Canada is aware and looking into a fix. Any solutions for others?

GM- T FORUM MEMBER SOLVED: SD card switch was toggled to the “Read Only” position. Changed to “Read/Write” to allow system to Initialize card.

 

3. Door lock loop.

- the truck has settings to choose door lock and unlock modes. Due to my work, I end up in unsafe locations where I require my doors to remained lock when I shift to park, and also only my driver door to unlock when I approach the vehicle. This has already prevented me from unwanted individuals trying to jump in at the same time or unknown people trying enter the vehicle when I pull over and park.

My issue is, no matter what, when I get out of the vehicle after driving, close the door. When I press the handle door lock, I have to cycle through

A) driver door unlock (it’s already unlocked, i just got out).

B ) all doors unlock.

C) all doors lock.

This is annoying and unsafe as I have to stand there pressing the door button three times slowly to lock, and if I press to quick I miss and leave all doors open. Tinted windows mean I have to press my face against to see. (Yes I can take my fob out of my backpack or pocket and press lock - but why did I pay for the system then?). Again, all the other vehicles allow me to lock the doors immediately with a button press when I exit - no hassle. (And unlock with the touch of the door handle - Sierra apparently didn’t pick up on this feature?).

*Is this normal? (It can’t be, it’s ridiculous) Dealership told me they fixed the issue (they did not). Then later told me they are ordering some part that might be holding down some other thing. I asked for a real explanation from the tech, but he was busy. Asked for a call, no call back.

DEALER CONCLUSION: If door is manually opened from the interior using handle (pull twice: unlock, open door) then the Body Control Module (BCM) does not receive a signal and believes the door remains locked, despite the door opening and the key being detected transitioning from interior to exterior. Pressing the button initiates the lock sequence from a locked state despite the door being in the unlocked state. "The system is just not as smart as others."

 

4. Door delay lock.

- following the above. I decided to use the “delayed door lock” feature to ensure I wasn’t leaving the door unlocked. This feature locks the doors after a few seconds of the key leaving. However it got annoying quick as unless I run around to the other side to get my kid out, it locks the doors. Then, for camping it’s very annoying. I turned off setting under my and my wife’s profiles. However, it won’t turn off. No matter what. Anyone run into this? Haven’t told the dealer yet as they don’t seem to know and are waiting on a part to schedule me back in. For the 4-5 time I. Just over a 6 weeks.

SOLVED: Dealer kept changing lock settings to "delayed door lock" thinking they were providing a alternative solution for locking the truck on exit without informing me. I would turn it off and each time I brought it in for the above loop, they were turning it back on if I had turned it off.

 

5. Parking assist.

- I noticed that while driving, my rear parking assist and cross traffic alert randomly disable. There is no sound and I only catch it when I see the message pop up briefly on the DIC. I assume it’s related to the dealer replacing the rear bumper prior to me buying the truck following some mishap that scratched/dented the bumper.

DEALER SUGGESTION: Can't replicate. Will not unplug or interfere with current setup in hopes that it will cascade into a larger detectable error. Claimed that if they tried unplugging and re-seating the connectors  it may "reset" the problem to an earlier undetectable state. If it happens again "please bring it to a closer dealer to review". ...implied it's a lot of work to remove the parts to get at the connectors and not worth the trouble to open up, but please make it someone else's problem : )

 

6. Driver Mirror Vibration

- There is quite a bit of driver mirror vibration at speed. It appears that wind is catching the mirror. This does not happen with the passenger mirror. There is so much vibration at times that the mirror is unusable for clarity, only that I have a vehicle with headlights madly dancing on the road behind me.

1st Dealer Suggestion: so far dealer stated the tested out several 2020 sierras and this is a similar issue. To them this was a solution.

2nd opinion Dealer Suggestion:Took the issue to a different dealer. They advised to replace the mirror assembly. Determined that the mechanical pivot point is faulty.

 

 

Sorry for the length. I just need help from some knowledgeable owners that can help out. Details are helpful!

 

 

 

 

 

Sent from my iPhone using Tapatalk Pro

 

 

 

 

 

 

Edited by aragrev7
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For #3, what happens if you hit the lock button on the inside of the door as you're getting out then pull on the handle after you get out to make sure it's locked? 


Thanks for the input! Yes this works (tried before), and as long as I have the key far enough from inside that it doesn’t think I’m locking the key inside I believe.
However, I’m not looking for a work-around, I’m trying to determine if the truck is working right (I don’t think it is), it’s only a few weeks old.
On top of that, when I pull my kid out of the backseat (or tools, etc), this means I then have to then open the front door again to lock all the doors, or leave it open and come back to it (or press the button three times).

I know it’s seems picky, but when I buy a vehicle, I test everything out, all features, drive mostly without radio or music (except to test) to hear the vehicle and listen to its “normal”, so I can identify when something breaks, needs attention, or is not functioning the way it should. :)


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Reply for number 2. Your SD card is in the Read Only mode. Pull it out of the slot and move the tab to Write. You will  only have to press "OK" one more time.

Oh my, if you are right, you’re a hero! But also still helpful regardless for chiming in!


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Glad I could help. I had to read through numerous pages to find the answer on one of these forums.

Worked! Thanks again. I’ll have to let the dealership know because according to them, GMC is stumped about it too. Now it makes sense!


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As far as I can tell the way you described #3 is the way it works. Back on my 2014 Sierra. I used to get out of the truck and hit the door lock indicator. The one by your left shoulder on the window sill. That locked all doors at the same time when I got out. Then I got a 2016 Sierra and that did not work for some reason. I looked for a setting but, didn't find it. I now have a 20 Sierra and discovered a few weeks back that this actually works again. So now when I get out of the truck. I don't hit the button by the inside handle or the outside handle. I hit the up and down lock indicator on the window sill. It locks all the doors and I'm good.

 

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Quick update - I added the outcomes to the noted problems for future searchers. Also added a new issue.

 

6. Driver Mirror Vibration

- There is quite a bit of driver mirror vibration at speed. It appears that wind is catching the mirror. This does not happen with the passenger mirror. There is so much vibration at times that the mirror is unusable for clarity, only that I have a vehicle with headlights madly dancing on the road behind me. The vibration is audible through the window that parts are contacting.

* so far dealer stated the tested out several 2020 sierras and this is a similar issue. To them this was a solution.

Is this the same with others on 2020 Sierras???

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9 hours ago, aragrev7 said:

Quick update - I added the outcomes to the noted problems for future searchers. Also added a new issue.

 

6. Driver Mirror Vibration

- There is quite a bit of driver mirror vibration at speed. It appears that wind is catching the mirror. This does not happen with the passenger mirror. There is so much vibration at times that the mirror is unusable for clarity, only that I have a vehicle with headlights madly dancing on the road behind me. The vibration is audible through the window that parts are contacting.

* so far dealer stated the tested out several 2020 sierras and this is a similar issue. To them this was a solution.

Is this the same with others on 2020 Sierras???

No, this is not a common issue and even if it was, its wrong and needs to be fixed.  If this dealer wont fix it, take it to another.

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11 hours ago, Gangly said:

No, this is not a common issue and even if it was, its wrong and needs to be fixed.  If this dealer wont fix it, take it to another.

I don't know if any of you guys have been to dealers before with previous vehicles out of warranty but it was always a night and day difference in attitude towards fixing things from my experience. They have no issues throwing parts at your car if GM is not on the hook for the tab, i guaranty if you were out of warranty they would of told you they need to replace the entire mirror assembly. GM just loves to use the "working as intended" line today, to get out from fixing little issues like this! Maybe i just don't see the point in saving petty amounts of money in fixes that could potentially make a customer actually happy about their purchase.

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I don't know if any of you guys have been to dealers before with previous vehicles out of warranty but it was always a night and day difference in attitude towards fixing things from my experience. They have no issues throwing parts at your car if GM is not on the hook for the tab, i guaranty if you were out of warranty they would of told you they need to replace the entire mirror assembly. GM just loves to use the "working as intended" line today, to get out from fixing little issues like this! Maybe i just don't see the point in saving petty amounts of money in fixes that could potentially make a customer actually happy about their purchase.

I’ve definitely encountered this. Also, in Canada, on the Acura/ Honda side, despite the US company having tech bulletins & recalls for issues, we often don’t get them right away, so despite having the problem with a clear link to the TSB, I’ve been turned away until I produce the docs myself (and even then) or spend the time arguing for it. - dealer: “we don’t have access to US tech database - they don’t share their info with us” - ok here it is. : )


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