Automatic Emergency Braking Problems of GMC Sierra 1500 - part 1

While driving at approximately 60 mph on an open road with no obstacles present and no braking input, the rear wheels spontaneously locked up without warning. No brake pedal input. No warning light prior to the event. No obstruction in the road. The vehicle has been subject to an active manufacturer recall for rear wheel lockup due to transmission control valve failure. The dealer's own diagnostic system generated a report showing six active fault codes in the following days including lost communication with the brake system control module and transmission control module. These codes were not addressed on the repair order. The dealer attributed the lockup to an automatic emergency braking activation without diagnostic confirmation and performed no repair. The manufacturer's own internal bulletin dated January 22, 2026 acknowledges the exact fault codes present on this vehicle as a known defect. The dealer cited this bulletin to dismiss the concern while stating no problems exist. A persistent brake noise has been confirmed by two separate authorized dealers across three visits with no repair performed at any visit. The vehicle has required five dealer visits in 77 days of ownership with 1,729 miles. The defect remains unresolved and poses serious risk of loss of vehicle control at highway speed.

I am the owner of a 2026 GMC Sierra 1500 denali ultimate equipped with the 6. 2l v8 l87 engine (VIN: [xxx] ), purchased new approximately three months ago. I am filing this complaint proactively. I have experienced no engine failure or symptoms to date. However, I am filing based on a documented pattern of l87 engine failures in 2025 and 2026 production vehicles, confirmed by multiple gm dealership technicians, which suggests that the manufacturing defect underlying NHTSA recall 25v-274 may not have been fully resolved by gm’s stated production improvements dated June 1, 2024. Nhtsa recall 25v-274 (April 2025) covered 597,630 vehicles from model years 2021–2024 for catastrophic l87 engine seizure caused by connecting rod bearing failure and crankshaft defects. Gm excluded 2025 and 2026 model year vehicles based on a claimed manufacturing fix. However, multiple 2026 production vehicles have since experienced the same bearing failure at extremely low mileage. Open NHTSA investigation ea25007 is already examining vehicles outside the original recall window, and recall query rq26001 is investigating the adequacy of gm’s remedy. I am requesting that NHTSA consider expanding the investigation scope to include 2025 and 2026 model year vehicles. As a 2026 owner of a $90,000+ truck with the identical engine configuration, I believe my vehicle warrants inclusion in any expanded investigation or recall action. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

My 2023 GMC sierra has 60,571 miles for a while now while driving the transmission slips and slams into gears. Recently driving with my kids in the car on highway going 70mph the back brakes locked up multiple times, so scary and dangerous while driving. I now currently have a code p-0747 in the system.

See all problems of the 2023 GMC Sierra 1500 🔎.

The brakes suddenly activate and cause the vehicle to rapidly stop with no warning of any kind and without any braking action being taken by the driver. Then, the brakes do not release and the vehicle cannot be moved as the brakes remain on. Turning the engine off and then restarting it or shifting to other gears does not release the brakes. The vehicle remains immobile and cannot be driven. After a few hours have passed, like overnight, the brakes release and the vehicle can started and driven just as if nothing had happened. A message briefly appears on the vehicle information screen each time this inadvertent braking occurs. It reads, “brake failure system”. These brake lockdowns occurred when driving on streets and in the driveway. No accident resulted but could have easily occurred. This is dangerous for a driver and occupants of a vehicle with this safety flaw as well as for other people and vehicles in the vicinity. This has happened five times. The last two instances resulted in the vehicle being loaded onto a tow truck and taken to a dealer of the vehicle’s manufacture. Thus far the dealership has not found what may be causing this intermittent braking problem.

See all problems of the 2020 GMC Sierra 1500 🔎.

This complaint involves a sudden failure of my vehicle’s anti-lock braking system (abs) and forward collision warning system, both of which are critical safety systems. While driving my [xxx] son to school, multiple warning lights suddenly appeared on the dashboard without any prior indication of a problem. The vehicle displayed a warning message instructing me not to exceed 36 miles per hour, and several system alerts activated simultaneously, my abs brake system failed and a transmission failure warning. These issues appeared suddenly while the vehicle was in normal operation. Prior to this incident, the vehicle had been functioning perfectly. The evening before, I had driven the vehicle to pick up my son from wrestling practice with no issues. The following morning, during a routine trip to school, these critical safety warnings appeared without warning. Because the warnings involved the braking system, I immediately took the vehicle to beach Buick GMC for inspection. The dealership diagnosed the issue as a software failure affecting the braking system and informed me that the vehicle required a software update and system download in order to restore proper operation of the brakes and related safety systems. I was required to pay over $300 for this repair because my vehicle is approximately 3,000 miles outside of the warranty period. However, I believe a failure involving the braking system and safety warnings should not occur suddenly in a properly functioning vehicle and should not be treated as a normal maintenance expense. I contacted **general motors customer service to ask why a failure involving a critical safety system would not be covered or investigated further. The only explanation provided was that the vehicle was outside of the warranty period. I requested a written explanation of their decision for my records, but I was told that providing written explanations is against company policy. I have more to say but I am out of characters. . . Information redacted pursuant to the freedom of informa.

With no warning truck just started jumping in neutral after take off from red light litterly almost getting hit from behind and on coming traffic and than I let off the gas pedal than it jerks back in gear and doesn’t want to stop and wants to jerk to keep moving like transmission won’t stop pulling had to turn truck off it is something electrical in transmission I can pull fuse and it resets than it’s normal till it decides to do it again I’ve got on line and notice there is a lot more of the same truck and year having same issue and people have complained also mechanical at dealer says they have had many complaints on same issue I need my truck fixed it gave no warning and is to dangerous to drive like it is.

See all problems of the 2010 GMC Sierra 1500 🔎.

My truck braked for a vehicle that was parked on the side of the road. This vehicle was not in my lane or hazardous in any way. I was traveling at highway speed 55 mph and truck braked to 30 mph approximately with no pre warning this has not happened before or after. The truck has about 26k on it.

See all problems of the 2024 GMC Sierra 1500 🔎.

I drove into my driveway put vehicle in park put my window shades up and vehicle went into drive and hit my garage. I had no warnings and this was caught on my ring camera. The ring camera caught my headlights lite up on outside edge and lights kept blinking off an on like there was some kind of glitch. My. The vehicle did not brake either. I saved the video. [xxx] information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

See all problems of the 2025 GMC Sierra 1500 🔎.

I am reporting a critical issue with the transmission. The transmission frequently slips, hesitates, and jerks unexpectedly during acceleration and gear shifts. On multiple occasions, the vehicle has lost power or failed to respond while entering intersections, merging onto highways, or attempting to accelerate—posing a serious safety risk. The issue often occurs without warning and has worsened over time. Additionally, there are instances of harsh downshifting, delayed engagement from park to drive, and sudden lurching forward or backward, which could easily result in a collision. Despite visits to the dealership and complaints made, the issue has not been resolved, and I’ve learned that many other owners of this same model have reported nearly identical symptoms. This appears to be a systemic problem with the transmission system. Given the safety risk, especially in traffic and at high speeds, I strongly believe this defect warrants immediate investigation and a formal recall.

See all problems of the 2015 GMC Sierra 1500 🔎.

I was traveling on the interstate, going a little over 70 mph as I was passing a tractor and trailer. There were no other vehicles in front of me. Suddenly the truck jerked like the breaks were being applied and my speed was quickly reduced to around 60 mph. The heads up display showed a crash alert orange symbol. I pushed the gas to try to get back up to speed but the truck would not accelerate and the speed kept dropping. I pulled over to the berm and came to a stop. There was a message on the message center but it went away before I could read it with everything else happening. I put the truck in park and waited a minute then I pulled back out and was able to get the truck back up to speed and home. I plan to contact my dealer tomorrow. The ruck was involved in an accident that damaged the front in earlier this year so I believe some or all of those sensors have been replaced. This is the first issue we’ve had since purchase. If there would have been a vehicle following behind me, the rapid breaking/deceleration could have caused an accident. Also the inability for me to regain my speed when traveling on an interstate was a danger to myself and others.

Twice in the past month +. On [xxx] my wife and I were on our way to a family wedding and I was driving approx 75 mph on [xxx]. I don't recall if I had cruise control on or not as I rarely use it. There was no vehicle was in front of me for hundreds of yards yet all of a sudden the vehicle started to brake very hard. I accelerated as I did not know what was going on and I had a car in back of me that started to gain. Then last Friday ([xxx}) with my wife following me in her car on [xxx] through ellicott city MD I was traveling at approx 25-30 mph through a very small historic town when all of a sudden the same [xxx] thing happened. Def no cc on . When we got to our destination I asked my wife if she saw my brakes come on suddenly?. She replied yes and said she saw the truck dip hard. I told her the brakes did it again. She said I should call the dealer. I did not as they are useless! then the electronics. On star has a catalog of my complaints. The radio selections I make just disappear from the screen: apple car play disappears from the touch screen and just goes dark. I have to stop the truck. . (per on-star) open the door. . Get out. . Lock it. . Wait 2 minutes. . Get back in . . Restart the truck, and this re-sets the computers(s). Ridiculous! I do not have sirius but the radio goes dark often for about 2-3 seconds. , then comes back on. I was told it is my I-phone is causing this. [xxx]! what does my phone have to do with am/fm radio?? I was told by GMC there is a patch to update the software. Koons GMC told me there was no such patch nor recall. I paid nearly $80,000 for this piece of [xxx]! information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Recently when starting truck brake message alert comes across on dash reading brake error, and not to drive above 45 miles per hour and brakes are not totally operational, meaning brake pedal has alot of play in it to bring truck to a stop. Have to turn off vehicle , sometimes repeatedly before it apparently resets computer system. This has now occurred four times in last five months. Events and dash warning message very similar to recall issued 3/3/20, but listed as "complete" on recall data base. Need to seriously and immediately looked into and corrected!.

On a normal trip to work the dash light lit up then gave me these warnings. Service esc, service trailer brake, brake system failure-62 mph top speed, steering assist reduced. Dashboard lights that were on, abs check engine, brake, traction control. When I tried to slow down the power assist was gone on the brakes, I had a little braking when I pushed the pedal all the way to the floor as hard as I could, when I went to turn the wheel was hard to turn. I have had no issues like this before. After I managed to stop and turn off then on the vehicle everything came back expect for a warning to service the trailer brakes and the check engine light was still on. It all cleared after a few more restarts. I got the truck to the dealer 4 days later and they said it was the battery going bad even though I was not having any problem starting the vehicle, I had them replace the battery. I am unsure if the problem is resolved, time will tell. What I am sure of is if my daughter had been driving the truck, she would not have had the strength to get the brakes to work or turn the wheel, she would have had a accident for sure.

See all problems of the 2019 GMC Sierra 1500 🔎.

I have had no issues with my vehicle since I purchased it in July 2022 and keep up with the routine maintenance on it. About 2. 5 weeks ago I was driving to work like I normally do and the truck started making a knocking noise and all these sensors lights came on the dash. The alerts were saying to service the parking brake, service esc, and that steering assist is reduced and to drive with care. The vehicle also started shaking and would not accelerate properly or shift gears. We ended up taking it to the closest GMC dealership and they were in able to diagnose it just by simply hooking it up, they had to fully dismantle the engine in order to diagnose it. They came back and said cylinder number 4 is damaged as well as the lifters and cam shaft. I am no car expert but it is weird that a car that is relatively new and has the maintenance kept up on it should not experience a serious malfunction like this. What is even weirder is my sister in law has a 2020 chevy silverado where the almost identical thing just happened to theirs and it too is now in the show as well needing its engine and stuff repaired.

When I put the truck in 4wd the dash says service stabilitrak and the traction control light and abs light come on.

See all problems of the 2011 GMC Sierra 1500 🔎.

Truck thinks I’m about to run into something and slams on its brakes. Last time it sent my sister to the hospital to get 6 staples in her head. Digital cluster goes on and off as well as the infotainment center. Transmission bangs and shifts horribly. 900 miles on the truck with a check engine light and transmission warning.

At 103,000 my 2020 at4 5. 3l v8 had a p0307 code thrown. Cylinder 7 misfire. Driving highway speeds, sudden loud pop and then the service engine light came on and automatic braking engaged, and the idle got extremely rough. Ended up being a bad lifter, bent rod, tore lobe off of the camshaft. Roughly 8,000 for the repair, new cam, new lifters, spark plugs and coil packs. Now only about 3,000 miles later, driving, sped up to pass on the interstate and another misfire, p0306 this time cylinder 6. Same symptoms check engine light, automatic braking, rough idle. Seems to be another failed lifter and bent rod. Currently awaiting diagnostic for this second misfire issue. When speaking with the tow truck driver and the mechanic both mentioned a significant rise in cases like this. There is definitely something wrong with the design that the manufacturer needs to be help responsible for. I have less than a month ago replaced all the lifters only to have another one fail again.

Drive train:the truck suddenly lurches forward as I'm accelerating and after I've stopped. It's very scary to stop behind a vehicle and suddenly lurch forward. Thankfully, I don't stop too close to another vehicle. The truck also shudders and experiences significant delays in acceleration after coming to a stop and going again. Automatic emergency braking: the automatic emergency braking system spontaneously brakes as I'm driving when there is nothing in front of me. Thankfully, nobody has been following behind me when this happens yet. I had to turn the automatic braking system off in order to avoid being hit.

See all problems of the 2018 GMC Sierra 1500 🔎.

Lifters failed in November 2023 and had repaired major engine damage including 4 cylinders, cam shaft, lifters, gaskets etc. After major repair work done. Truck is now doing same exact thing in January 2024. The dealership is stating they will not look at the vehicle unless I buy a new battery. I asked them to try a used battery to see if that makes a difference. And then if it is the battery I will replace. I was hung up on after the technician doug pedersen stated ill have a supervisor call you back.

I put my truck in break. Service mode to replace the brake pads. I began changing the pads and could not get the piston to retract all the way, I hooked uon a c clamp to retract the piston. In the event I moved the rotor to another spot and the brake service mode turned off and the piston extended. My fingers nearly got caught in the caliper. When put in brake service mode, it should not automatically extend when turning the rotor. Someone will get hurt bad at some point in a swrvice garage or at home when wirking on brakes.

Abs light limited to 43 mph esc system steering assist reduced service trailer brake system engine light on.

Question #1- “service trailer brake system”-“steering assist is reduced drive with care”-brake system failure 43 mph top speed”-“service esc” question #2- I experienced a complete loss of braking ability, myself, a friend and, a coworker, as well as the properties around me where placed at risk. Question #3 not yet I am having towed to the dealer today. Question #4 not yet the vehicle will be towed to the dealer where I purchased it today. Question #5 not my knowledge I do not recall any warning lights.

Traveling at 70 mph on cruise control, tapped breaks to turn off, multiple warning lights flashed, vehicle lost power, and breaks with multiple messages including “break system failure, top speed 62 mph”. I lost all breaking control on the highway and nearly crashed into other vehicles due to inability to stop. Was able to pull over, turn off vehicle, and turn back on, when the breaks were working again but the vehicles acceleration was very slow. Currently at authorized repair shop. When dropped off, there were 8-9 active codes.

What happened: the air bags failed to deploy during a crash. Question: what component or system failed or malfunctioned? answer: air bags, automatic emergency braking, forward collision warning. Question: is it available for inspection upon request? answer: yes question: how was your safety or the safety of others put at risk? answer: driver-side air bags failed to deploy upon a rear-end collision with the vehicle to my immediate front @ 40 mph. Question: has the problem been reproduced or confirmed by a dealer or independent service center? answer: no. It currently is at a repair facility as of this morning and it’s apparent that the air bags did not deploy. Question: has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? answer: no, and not to my knowledge since turning the vehicle into the repair facility this morning. Question: were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? answer: none. No previous warning lamps, messages, or symptoms. *note: I have dash cam video of the collision in my possession.

Were driving and vehicle repeatedly suddenly braked in the middle of interstate or highway without any warning. We are so traumatized, and scared of this vehicle. It has happened before. Dealership says there is nothing they can do. This could have caused our life. GMC should be held accountable.

I were driving at low speed and all 4 wheels locked causing the vehicle to suddenly stop without notice. I almost got rear ended. I had to put vehicle in park and turn off and turn back on to get it to move. Again it did the same thing stoping with brakes locking suddenly, almost causing an accident in middle of road. There was no warning at all.

There has been a recall on the assisted braking pump. My truck is not on that recall as of now. But I am having the same braking trouble at slow speeds. Is there any way the company will fix this issue.

See all problems of the 2017 GMC Sierra 1500 🔎.

I was pulling in to a parking spot and pressed the brakes and the truck didn’t stop and I hit the sign. When I looked at the dash there was a “service brake assist “ warning on.

Braking vehicle will cause brake pedal to vibrate and become soft while pressing it and requires more effort to stop vehicle. Service brake assist light laminates on info system. I know there is a recall for this currently but my vehicle is not listed for this all though I have the same issues. Recall is n202300860.

The service message appeared on the display after backing up "service brake assist" I searched this issue and found over 65 complaints for this vehicle year/make /model. I am at work and fear driving home as this issue has resulted in brake failure on some of the complaints noted. I have not contacted anyone yet, I wanted a recall notice as this is a safety issue and we cannot afford any costly vehicle repairs.

The forward collision assist and lane keep assist are suddenly not working. This seems to be a software or eletrical issue.

See all problems of the 2022 GMC Sierra 1500 🔎.

Trailer brake system warning.

Truck drove as expected with no prior warnings. We pulled over for road snacks/drinks upon starting the truck we got a whole slew of warnings and warning lights. The warnings included:. Service esc, service trailer brake system, service brake assist, stering assist is reduced drive with care and finally brake system failure 43 mph top speed. The check engine light, traction control off and brake light stayed on. We slowly drove to an o'reilly's and got the odb code p25a2 (1 of 2 stored) and p25a2 (2 of 2 pending). I then noticed I had an email notification from onstar advanced diagnostics: this is a diagnostic alert for your GMC sierra. Dear victor rubio, an issue with the antilock braking system in your 2022 GMC sierra has been detected. Please service your vehicle within 7 days. The following morning the truck was was started and all seemed normal like nothing ever happened, no warning lights or warning messages our of concern we dropped off at garlyn shelton Buick GMC service center to diagnose the issue. They reported finding code c05b0 for brake fluid leak. Further states no external leaks found, brake fluid test passed 2 of 3 times, recommend needs master cylinder assembly but no replacement parts available.

Trailer brake system is blinking to much.

See all problems of the 2014 GMC Sierra 1500 🔎.

Panel message with beep saying: service trailer brake system.