2020 GMC Sierra 1500 Brakes

I was driving my 2020 GMC Sierra 1500 on a local street when the dashboard suddenly displayed a “Brake Failure” warning. I immediately realized I had no braking power and had to safely roll into an uphill parking space to stop the vehicle. While waiting for the tow truck, I researched the issue and discovered there is a known recall related to the brake calipers on some 2020 Sierra 1500 models. However, when I entered my VIN, it showed no open recalls. I also contacted GMC directly, and they confirmed that there are no active recalls associated with my vehicle. Additionally, the vehicle's onboard information system indicated that the front brakes were at 65% and the rear brakes at 80%, suggesting that brake wear was not a contributing factor.

My vehicle displayed numerous brake failure codes and limited my speed to 43mph. When taken into my local GMC dealer the diagnostics I was given were a bad/leaking master cylinder. This vehicle has 16,200 miles on it and was never used for towing or hauling. The brakes are hard and brake assist has clearly failed. I’ve found numerous recalls and issues with other year vehicles from GMC, yet they are denying any liability on my vehicle. They want over $3000 to replace the master cylinder even though there’s no physical leak observed via fluid loss. This is a major safety concern when a major brake component fails on such a low mileage vehicle. This truck also has a well known seal leak on the rear window that causes mold to grow inside of the vehicle cabin. Apparently no one has died yet so they have not been forced to put out a recall. Consumers should not be forced to spend thousands of dollars on major components on such low mileage vehicles. Especially when it comes to safety items like braking. I’ve researched this for hours and have found this has been a known issue on these 2020 models many people. Some even brand new after driving them off the dealership lot. Clearly there is an issue and the manufacturer refuses to address it.

I will start by saying that I have had this issue since I had the truck (2020), less than 10k miles. I mentioned to the dealer multiple times. I was told that they can't figure it out since it has to be doing it while it is at the dealership to figure it out. I am finally fed up with that answer. The issue is with trailering. It will randomly lose trailer brakes while driving down the road. Sometimes the brakes will come back right away, sometimes they will not. Other times other lights that should be working will randomly stop working as well such as turn signals. This has happened multiple times and I only tow a few times a year when I pull my travel trailer. I have a video of it doing it as I am driving down the road. For the additional details with approximate date that this incident occurred, I will put the last date that this was found.

Brake monitor repair keeps illuminating since 2/1/2025! Replaced all brakes and rotors, yesterday 4/27/2025. now don't drive over 43 mph illuminates, emergency brake illuminates says push brake peddle to disengage parking brake yet parking brake has never been engaged

On Monday, [XXX], at about 1730 hours was traveling Southbound at 45mph on [XXX] approaching the [XXX] intersection. Vehicle alerted to the following codes on the dash; ESCAPE, Traction Control, Check Engine Light, Brake System Failure, "Do not exceed 62 MPH". I took foot off accelerator and looked up and noticed the traffic light turning red. I applied pressure to the brake and noticed there was no brake pressure at all, and the vehicle continued to roll forward towards the intersection. I put the truck in low gear to slow and continued to pump the brake rapidly. As the truck gradually slowed I turned truck off until it came to a stop. When I restarted the truck the brake hydraulic pressure returned and only the check engine light remained on. I took the truck to Reliable GMC in the Roseville Automall the next morning. The service department claimed the AGM Battery was bad and caused the front brake caliper sensor to throw a low voltage code causing a cascade event of codes throughout the system. The loss of my brakes nearly caused me to enter an intersection unwillingly and could have led to a serious accident. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My pickup was specifically purchased to pull a duel axle trailer ( brakes required by Fl. Law). The trailer weights more than the pick up. They stopped working with the electric /hydrolic Trailer brake system. I have had the Sierra in three times for Warren Ty repair. They never fixed the system. I have thoroughly test the trailer system - it works fine with another pickup. Dealer won’t return my calls. Multiple trips taking it in for this problem. Have a case filed with GM. All just placating me, now ignoring my problem. I am stuck and they are not acting in good faith.

Lost break, second time this month, showing break failed 40 mph max speed, abs light on, break light on, and 2 more light on the car with antislipiring or something like that, the another one no idea what it is

The contact owns a 2020 GMC Sierra 1500. The contact stated while driving 60 MPH, the service brake, check engine, and ABS warning lights were illuminated. The contact took the vehicle to an independent mechanic to be diagnosed and it was determined that the passenger’s side rear caliper needed to be replaced. The vehicle was not repaired. The vehicle was taken to the local dealer to be diagnosed, and the contact was informed that the rear passenger’s side caliper needed to be replaced. The vehicle was not repaired due to the parts not being available. Upon investigation, the contact associated the failure with NHTSA Campaign Number: 20V116000 (Service Brakes, Hydraulic) however, the VIN was not included. The manufacturer had been informed of the failure. The failure mileage was approximately 69,000.

We were hauling a trailer and driving approximately 65-70mph with cruise control enabled. The vehicle randomly disengaged cruise and the ABS telltale illuminated, lost brake functionality completely. Safety of my family and other vehicles around us was compromised! Downshifted to try and navigate the vehicle to the side of the road and the ESC warning text came on the screen. Was able to luckily stop vehicle by downshifting. Turned off ignition and then cycled back to run, brakes and all warnings were cleared. Started driving vehicle with flashers on the side of the road see what would happen and approximately ten miles later same thing happened but this time brake functionality was reduced significantly but not completely but still had to downshift to stop. Called GMC and was told this was not a recall even though vehicle brakes randomly stopped working. Told us they would do nothing since the vehicle was out of warranty 80k miles and warranty was 60k and also since no one was hurt. We were 1-2 hours from being in the Mountains driving and not sure we would be here today if this had happened in the Mountains! Dealership ordered a new master brake booster and ABS. When installed the part would not flash and GM engineering told them to replace the part a second time.They we’re told to keep flashing till it takes even though the second module was also bricked. Seems strange a new part would be broken as well and the master cylinder was resetting. Dealership states the vehicle is fixed but the safety of my family and others driving around me were in extreme danger when this happened. Do not feel safe driving this vehicle and not convinced this will not happen again. When we called GM they told us they are receiving many calls about this happening to AT4 vehicles but they have not issued a recall yet. Submitting this because vehicles should not randomly lose brake functionality and do not want others at risk or my family.

Brake pad monitoring system alert came on driver information center warning screen. Brought to local dealer who told me I needed new brake pads. There is a current safety bulletin on the NHTSA.GOV website for the 2019 model year GMC Sierra, as well as the 2019 Cadillac CT6, but not he 2020 model year. The week prior my driver information center reported front brakes in the high 80's and the rears in the low 90's in terms of percentage of brake life remaining. How can the system go from being safe to being unsafe in a week (and less than 200 miles)? At this point I don't know if my vehicle has a safety problem with my brakes or if there is a sensor and programming issue as described in recall N192264451. I have no observable issues while braking - no pulsing, noise, chattering - that would indicate any brake problems. My only inclination is the alert on the driver information center. Both local dealer and GM customer service are telling me to perform service and pay out of my pocket. This seems inconsistent based on the above recall.

This vehicle was involved in a fatal crash when it rear ended an SUV stopped at a red traffic light. The driver alleges mechanical failure of the brakes. Police performed a vehicle download which captured 5 seconds of pre-accident data. The download shows the accelerator pedal was fixed at exactly 57% the entire 5 seconds pre-crash while the driver simultaneously applies the brakes the entire 5 seconds. A city bus captured the crash on a dash camera. Despite the driver desperately applying the brakes, the vehicle's speed continued to increase and the driver was unable to avoid the collision, and burst into flames upon impact. The vehicle mileage is less than 2,500.

Brakes have been squealing since 4000 mile mark. Dealer states it’s normal.

THE ABS SYSTEM FAILED WHILE DRIVING DOWN THE ROAD CAUSING THE BRAKES TO LOCK UP AND CAUSED THE TRUCK TO SPIN OUT OF CONTROL NEARLY CRASHING INTO ANOTHER VEHICLE AND JUMPING OVER THE CENTER DIVIDE INTO ONCOMING TRAFFIC.

2020 GMC 6.2 L V8 1500 4W SIERRA DENALI. BOUGHT YESTERDAY NEW FROM DEALERSHIP. TODAY, NOT EVEN 120 MILES AND BRAKES MALFUNCTIONED. I STARTED TRUCK WITH GMC APP. GOT IN CAR WITH MY FAMILY AND AS I PULLED OUT OF PARKING STALL PUSHING ON BRAKES MET EXTREME RESISTANCE AND SLUGGISHLY CAME TO A STOP. I PUT TRUCK IN PARK. SHUT OFF AND TURNED BACK ON. BRAKES STILL NOT FUNCTIONING. 'BRAKES' 'ABS' AND ICONS FOR TRACTION CONTROL AND CHECK ENGINE LIGHTS WERE ON. AGAIN ATTEMPTED TO DRIVE. DRIVING 20 MPH WOULD TAKE GREATER THAN 50 YARDS TO STOP, WITH ME, 220# ATHLETIC MALE APPLYING FULL FORCE. WARNING MESSAGE ALSO APPEARED 'BRAKE SYSTEM FAILURE MAX SPEED 62 MPH'. NO IDEA WHERE 62 WAS FORMULATED. ALSO SOME MESSAGE ABOUT TRAILER BRAKES CAME ON TOO. NO TRAILER WAS ATTACHED. I SHUT TRUCK OFF. 30 MINUTES LATER STARTED, CHECK ENGINE LIGHT WAS ONLY LIGHT ON. BRAKES WORKED NORMAL. WAS ABLE TO CAUTIOUSLY GET 3 MILES HOME. THIS IS A POTENTIALLY FATAL FLAW. AGAIN THIS TRUCK IS STRAIGHT OFF THE DEALERS LOT. ONSTAR SENT EMAIL STATING 'ISSUE WITH ANTILOCK BRAKING SYSTEM, TAKE TO DEALERSHIP WITHIN 7 DAYS '. SO BRAKE FAILURE IS A MAJOR ISSUE. BUT ALSO A KNOWN BRAKE ISSUE AND THE COMPUTERS SAY STAY BELOW 62 MPH AND GET SERVICED WITHIN 7 DAYS ARE JUST AS WORRISOME. A BRAKING ISSUE SHOULD INSTRUCT DON'T DRIVE AND HAVE TOWED THANKS

VEHICLE WAS PARKED. ENTERED VEHICLE AND TURNED ON VEHICLE USING INTERIOR START BUTTON. VEHICLE WAS PUT IN REVERSE AND WAS BAKING WHEN ALL BREAK PRESSURE DISAPPEARED AND VEHICLE WAS ROLLING BACKWARD AND CAME TO A STOP BEFORE STRIKING ANOTHER VEHICLE AND CHILD. VEHICLE WAS PLACED IN PARK AND ESC FAILURE, TRAILER BRAKE FAILURE, TRACTION CONTROL FAILURE, POWER STEERING FAILURE AND DO NOT DRIVE ABOVE 62 MHP ALARMED ON THE DASH. VEHICLE WAS SHUT OFF AND ON 3 TIMES AND RESET FINALLY REGAINED SOME BREAK PRESSURE BUT CHECK ENGINE LIGHT CAME N. VEHICLE WAS TOWED TO TRENT GMC, NEW BERN NC FOR SERVICE. SERVICE TOLD US IT HAD A RECALL. I WAS UNABLE TO LOCATE A RECALL FOR THIS ISSUE. THIS COULD HAVE ENDED VERY BAD. I AM NOT ASSURED THAT THE PROBLEM IS FIXED.

TL* THE CONTACT OWNS A 2020 GMC SIERRA 1500. THE CONTACT STATED THAT WHILE DRIVING AT 52 MPH, THE BRAKE PEDAL WAS DEPRESSED BUT WAS VERY FIRM. THE PARK BRAKE WAS ACTIVATED BUT FAILED TO EFFECTIVELY STOP THE VEHICLE. THE VEHICLE WAS COASTED TO A PARKING LOT AND WAS PUT IN PARK. THE BRAKE SYSTEM FAILURE LIGHT, THE ABS AND SEVERAL OTHER WARNING LIGHTS ILLUMINATED. THE VEHICLE WAS TOWED TO THE BAKER BUICK GMC OF CHARLESTON DEALER, LOCATED AT 1621 SAVANNAH HWY, CHARLESTON, SC 29407) WHERE THE VEHICLE WAS KEPT FOR A DIAGNOSTIC TEST. THE MANUFACTURER WAS MADE AWARE OF THE FAILURE AND STATED THAT THE FAILURE WAS A KNOWN ISSUE AND REFERRED THE CONTACT TO THE DEALER. THE VEHICLE WAS NOT REPAIRED. THE FAILURE MILEAGE WAS APPROXIMATELY 7,020. THE VIN WAS NOT AVAILABLE.