Auto lock feature

SummitWhiteT1 · December 20, 2020

I recently traded my 19 LT for a 21 RST. On my old truck I could open and close every single door several times and afterwards my truck would auto lock as soon as all the doors were shut. On my new truck I’ve noticed that it doesn’t always do that even tho I believe I’ve enabled all relevant settings in the infotainment system. I don’t have the rear door lock buttons on my 21 like 19 had so idk if that may have anything to do with it?

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reno360 · December 20, 2020

I seem to be experiencing the same thing - or at least similar. I have a 2021 GMC AT4 and the doors automatically lock most of the time. They sometimes do not lock - just often enough for me not to trust it - ever - so I'm constantly manually locking the doors just to make sure. I originally thought it was because I was not exiting the field soon enough but I can't seem to recreate it in any form or fashion. I am taking my truck to the dealership tomorrow for some other work and plan on having them look at this also. I'll report back once I get an answer from them...

eckseleven · December 21, 2020

I've had my truck for about a month and have noticed it not lock a couple times. It seems to occur more when the last door I shut is a rear one. Mine is set to beep the horn when locking so I just always listen for that when walking away and press the button if needed.

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SummitWhiteT1 · December 21, 2020

Same here, always a rear door when it fails. It never happened on my 19

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smit303 · December 21, 2020

I disable the auto lock system. Personally don't like it.

Cjanik · December 22, 2020

I use it too, I have personally never had it fail on me.

Dpach · December 22, 2020

If you want the truck to lock by itself a few seconds after you get out so you don't have to hit the door button, there is a setting in the "vehicle" app in the radio settings. I believe it is under lock/unlock settings. It's called passive locking and you can set it up so it does it silently or does a horn chirp so you know it is locked.

If setting up passive locking doesn't work, then it may be a glitch.

eastex · December 24, 2020

I have used the passive locking system with the horn beep for over a month now. It hasn’t failed to lock yet with several tests of repeated unlocking and opening front and rear doors. I will probably continue to test with horn notification for another month or so before I trust it enough to turn off the horn notification.

Eastex

RWTJR · December 24, 2020

On 12/20/2020 at 6:04 PM, reno360 said:

I am taking my truck to the dealership tomorrow for some other work and plan on having them look at this also. I'll report back once I get an answer from them...

So, what did the dealership say?

reno360 · December 24, 2020

1 hour ago, RWTJR said:

So, what did the dealership say?

I just got it back last night - the had it since Monday to fix the passenger side mirror and a couple other items. They said the door locks were "functioning as designed" I suspect the just stood there while it locked (successfully) and moved on. I'll keep pursuing it on future visits.

RWTJR · December 24, 2020

38 minutes ago, reno360 said:

They said the door locks were "functioning as designed" I suspect the just stood there while it locked (successfully) and moved on. I'll keep pursuing it on future visits.

Thanks for the follow up. I am afraid that's the nature of intermittent issues and diagnosis.

I wonder if the passive locking is being overridden or signal blocked some way. I know the passive locking can be temporarily overridden by holding the unlock button down (there also may be some unpublished way). When this happens it won't passively lock until the next time the ignition switch is cycled (truck started). I manually override mine when cleaning or working on/in the interior. Or maybe some radio signal/interference that doesn't allow the system to recognize the FOB has moved out of the proximity range? You noted a correlation between failure to lock and a back door. Any other consistencies, location of occurrence, could a second FOB be near (significant other's purse or pocket) amount of time the door is open, etc., etc.? When it doesn't lock passively does it easily lock using the FOB?

Next time try walking up next to the door (to establish signal) then walk far enough away that it should lock. If it does lock, it may indicates a signal issue. If that doesn't work try opening and closing the door, or doors, then walk away and see if it locks. it may indicate the system is not recognizing all the doors are closed (or maybe all the doors aren't closed). Last try, starting the truck, turn it off, exit and close the door, walk away and see if it locks. If it locks, it may indicate the passive locking was overridden somehow and reset by cycling the ignition. Or any/all of this could be useless as I have no clue what I'm talking about.

I use passive locking all the time on both my truck and Camaro, so far without issue. I would miss the convenience if it wasn't reliable. I never have to think, did I lock the doors?

Please let us know if you get it figured out.

JMHO

No expertise implied or expressed

SV2100 · May 16, 2022

I know its been a while since this thread was updated but I recently purchased a '21 Silverado RST and I am experiencing a similar issue... I had a theory that the auto lock was overridden if a door was left open too long so I ran the following test... During the entire test I did not leave the range of the key fob so that may be another variable that was not taken into account.

Unlocked the truck with the driver door handle button. I then opened and left the rear driver side door open for about 40 seconds and then shut it. The auto lock did NOT engage.

I repeated this same experiment for 30 seconds, 40 seconds, 50 seconds, 1 minute... Auto lock DID engage all these times.

I then left the the driver door AND the rear driver side door open for, 30 seconds, 45 seconds, 1 minute... Auto lock engaged all these times.

I wasn't able to test much more since this was done at my office in the morning when i should be working... I'll try more things in the future and comment if I find anything definitive...