Parking (emergency) brake coming on by itself?

[Gerstein1989]

hey guys I spoke to my service guy about this issue and told me any time your truck in on an incline the truck will sense it and will automatically turn the parking break on. he said its very sensitive as well. Even if the truck senses that you're .1 of an inline it will turn it on. I tested this on the weekend. I parked on hills over the weekend and every time I got back in to leave my parking break was on. Its a safety feature. I don't think there is anyway to turn it off but just thought I would let everyone know that its normal.

[htoooh]

So, I was towing my 2019 Next Gen Sierra 1500 behind my motorhome after getting a Blue Ox baseplate and NSA tow bar installed.  I discussed with the tech whether or not I needed to disconnect the battery or pull a fuse and he said that as long as the steering wheel would turn without the key in the "on" position then I shouldn't need to.  About an hour and a half later I was stopped at a stop light and when I took off I looked back in the mirrors and saw smoke barreling out of the rear end of the pickup.  I pulled into the middle turn lane and found that the parking brake had engaged and it wasn't me that engaged it!!  I was finally able to get the parking brake to stay off by starting the truck, placing the transmission in neutral until I could pull off to a safe place.  I got out the owner's manual and it specifically states that the battery must be disconnected when towing as the parking brake can set itself automatically.  This experience cost me two new tires as dragging the truck to a stop put flat spots on each tire.  One tire was through the first set of cords while the other didn't get that deep into the tire.  Why, WHY, does GM do this??  It makes no sense.

[bamorris2]

So, I was towing my 2019 Next Gen Sierra 1500 behind my motorhome after getting a Blue Ox baseplate and NSA tow bar installed.  I discussed with the tech whether or not I needed to disconnect the battery or pull a fuse and he said that as long as the steering wheel would turn without the key in the "on" position then I shouldn't need to.  About an hour and a half later I was stopped at a stop light and when I took off I looked back in the mirrors and saw smoke barreling out of the rear end of the pickup.  I pulled into the middle turn lane and found that the parking brake had engaged and it wasn't me that engaged it!!  I was finally able to get the parking brake to stay off by starting the truck, placing the transmission in neutral until I could pull off to a safe place.  I got out the owner's manual and it specifically states that the battery must be disconnected when towing as the parking brake can set itself automatically.  This experience cost me two new tires as dragging the truck to a stop put flat spots on each tire.  One tire was through the first set of cords while the other didn't get that deep into the tire.  Why, WHY, does GM do this??  It makes no sense.

I’m really sorry for your situation and it sucks that it’s costing you two new tires. However, as you said, it’s specifically called out in your owners manual. I guess it’s a lesson for everyone not to take the word of a service tech when it contradicts the manual.

[htoooh]

55 minutes ago, bamorris2 said:

I’m really sorry for your situation and it sucks that it’s costing you two new tires. However, as you said, it’s specifically called out in your owners manual. I guess it’s a lesson for everyone not to take the word of a service tech when it contradicts the manual.

Yup, it's all on me.  I should have read the book.  However, even though we now know, I do find it unacceptable that the truck will set the parking brake without my knowledge or input.  I really hope GM rethinks this idea and corrects it.

[CamaroVetteGuy]

3 hours ago, htoooh said:

Yup, it's all on me.  I should have read the book.  However, even though we now know, I do find it unacceptable that the truck will set the parking brake without my knowledge or input.  I really hope GM rethinks this idea and corrects it.

I agree I don’t like the electronic parking brake

[dwilli]

Mine comes on periodically...not sure how often but as soon as I touch the gas it disengages so it shouldn't be a problem. And to the guy that says ALWAYS use your parking brake, in NE Pennsylvania where winters can be very cold and damp I was always taught NEVER to use the parking brake because it can freeze and be a real pain to release. You can sometimes put in reverse then back in drive, all depends on conditions. I'm 4+ months in with a '20 AT4 and LOVE, LOVE, LOVE this truck. 

[jlong1984]

On 6/15/2020 at 4:27 PM, bamorris2 said:

I’m really sorry for your situation and it sucks that it’s costing you two new tires. However, as you said, it’s specifically called out in your owners manual. I guess it’s a lesson for everyone not to take the word of a service tech when it contradicts the manual.

It's crazy to me how people will buy a $50,000+ vehicle and not do something as simple as reading the owners manual supplied with it. 

[Gerstein1989]

On 6/15/2020 at 5:24 PM, htoooh said:

Yup, it's all on me.  I should have read the book.  However, even though we now know, I do find it unacceptable that the truck will set the parking brake without my knowledge or input.  I really hope GM rethinks this idea and corrects it.

I think this feature is really good. If it detects your on a decline it engages it. It’s a safety feature. 

[Timmaaayy]

I think mine does this when it is close to solid objects when it is put into park (to prevent that slight rolling when put in park).

 

[Shae3838]

My 20 Sierra diesel has 6k on it. First my sound went out completely. Nothing for radio or auxiliary. When I let it sit a min and started it, everything worked. Then my parking brake set itself on a flat surface.  Then again on a slight incline. I thought this was weird since I just spent 5 weeks in KY ( I live in flat IL) and it never did that.  The idle sounded a little off today and now my engine light is on. My diagnostic report says "an attached device may be preventing the diagnostic test from completing. Unplug any devices from the diagnostic port and try again later." I have nothing plugged in to the port and not even a phone charger plugged in to my truck. 

[Shae3838]

I took mine in for service this week. They told me the parking break shouldn't be coming on by itself. Everything I reported seemed to be linked to the breaks. They read all the codes and said it was all network issues. Everything was up to date but they thought there might have been a glitch with the last update. They cleared the codes and everything seems good now.

[redwngr]

22 hours ago, Shae3838 said:

I took mine in for service this week. They told me the parking break shouldn't be coming on by itself. Everything I reported seemed to be linked to the breaks. They read all the codes and said it was all network issues. Everything was up to date but they thought there might have been a glitch with the last update. They cleared the codes and everything seems good now.

 

I think the tech is mistaken -- or is thinking about other situations than these:

 

(There have been other threads about the epb self actuating.)

At least 2 situtations when the epb may self actuate:  

 

Found this in the '21 Sierra manual.

Cut and paste from pg 246:

 

The vehicle may automatically apply the EPB in some situations when the vehicle is not
moving. This is normal, and is done to periodically check the correct operation of
the EPB system, or at the request of other safety functions that utilize the EPB. 

 

 

The electric parking brake can also come on to take over from the hill-start-assist system: 

Also from manual:

 

Hill Start Assist (HSA)
When the vehicle is stopped on a grade, Hill Start Assist (HSA) prevents the vehicle from rolling in an unintended direction during the
transition from brake pedal release to accelerator pedal apply. 

The brakes release when the accelerator pedal is applied. If the accelerator pedal is not applied within a few minutes, the Electric Parking Brake will apply. The brakes may also release under other conditions.

Do not rely on HSA to hold the vehicle.
HSA is available when the vehicle is facing uphill in a forward gear, or when facing downhill in R (Reverse). The vehicle must come to a complete stop on a grade for HSA to activate.

 

 

[Shae3838]

On 11/12/2020 at 11:28 AM, redwngr said:

 

I think the tech is mistaken -- or is thinking about other situations than these:

 

(There have been other threads about the epb self actuating.)

At least 2 situtations when the epb may self actuate:  

 

Found this in the '21 Sierra manual.

Cut and paste from pg 246:

 

The vehicle may automatically apply the EPB in some situations when the vehicle is not
moving. This is normal, and is done to periodically check the correct operation of
the EPB system, or at the request of other safety functions that utilize the EPB. 

 

 

The electric parking brake can also come on to take over from the hill-start-assist system: 

Also from manual:

 

Hill Start Assist (HSA)
When the vehicle is stopped on a grade, Hill Start Assist (HSA) prevents the vehicle from rolling in an unintended direction during the
transition from brake pedal release to accelerator pedal apply. 

The brakes release when the accelerator pedal is applied. If the accelerator pedal is not applied within a few minutes, the Electric Parking Brake will apply. The brakes may also release under other conditions.

Do not rely on HSA to hold the vehicle.
HSA is available when the vehicle is facing uphill in a forward gear, or when facing downhill in R (Reverse). The vehicle must come to a complete stop on a grade for HSA to activate.

 

 

Thank you for the info but I was actually talking about my situation...on a flat surface with no incline at all. It came on two different times then my engine light came on. That and all the little glitches I was experiencing were supposedly related to the brake system malfunctioning. I actually apply the break if I'm on any kind of incline. I do know that techs aren't always right, tho

[Travis C]

I just had a issue with the parking brake on my 2020 Trail Boss. I was driving and the cluster read some kind of fault with my parking brake and the check engine light started flickering then went off. When I was trying to come to a stop and before I used my brakes the truck would start shuttering. Like my e brake was on. Of course Chevy said there were codes but couldn’t find the problem lol. So, I definitely think there is a issue. Don’t even get me started with the infotainment system. 

[AONYX]

I use mine in the parking garage because I park about 3 inches from the wall and I don't want it to roll after placing it in park. It does seem like it comes on at random times in other places, but I haven't had an issue and just assumed I had set it myself.