2021 Gmc Sierra 1500 Brakes Problems

Left rear parking brake actuator malfunction. The truck would brake unexpectedly. The brake would not completely release at times. Took it to the dealer on June 6, 2024 and they replaced the rear rotors and pads. I asked them if the parking brake actuator was faulty and may have caused the premature wear. They laughed and said no, it wasn't possible. On Aug 7, 2024 I returned the truck to the dealer with the fault codes C1114 & C060B caused by a failure of the parking brake actuator. It was impossible to use the emergency brakes when the codes were present. For several months after the repair, brake faults would appear and disappear randomly. Took it to the dealer, and they found nothing wrong. Electric-actuated emergency brakes should be illegal.

The 2021 GMC Sierra 1500 has an Electronic Parking Brake (EPB) that bolts on to the rear calipers. The EPB does not release, in order for service, you have to long press the parking brake, then the truck goes into service mode & will release the brakes for service, some newer models may not have this feature. The vehicle has 36,000 miles on it & the inside rear brake rotors are worn down from the EPB dragging & not releasing as supposed to, causing excessive premature wear & that could cause a safety hazard fleet wide. The EPB should not be in use while the vehicle is moving, but it is coded to not release, meaning whenever you press the brake it never moves back out away from the rotor, causing drag & or even can cause warping of the rotor. I do not understand the thought process in regards to not letting the EPB release, it acts like the screw type caliper that would have the same issues of every time it moves out it will not go in until taken apart & screwed in, again meaning the brake pad is constantly dragging on the rotor which could in turn also affect the miles per gallon. I see the thought process to use EPB as useful but not a good execution by the manufacturer.

On March 10, 2025, I was driving down a residential street, about 40 mph, when the "Brake System Failure, 42 miles top speed," indicator light came on. Seconds later, I was approaching a stop sign and pressed down on the brake pedal. The brakes failed and the brake pedal went directly down to the floor. Luckily there were no other vehicles around and i was able to coast through the stop sign. I continued to coast until the truck stopped on its own and I was able to shift the gear into park. I've checked for recalls on my truck for this issue and did not find any. There is a similar issue with the GMC 2500 and 3500 series. Perhaps the issue is broader than expected.

We have had several times where we are on highway and our truck like slams on the brakes causing us to lose control. It was a recall on it and GMC fixed it and within the same week of them fixing it it happened 3 times back to back. Making my truck to force another car to steer out of my way and actually went off the highway. Thank god it was just dirt snd he didn’t get hurt or anything. But I am scared to even drive my vehicle! It starting Happening for about a year now. And it would only do it like every couple months but now it’s has done it 6 times in the last 2 months!

While towing a trailer in tow/haul mode on the highway traveling around 60mph, their was a strong downshift clunking sound. About 10 miles later, it happened again, except this time the brakes logged up and truck skid for about a full second and then trailer began fishtailing slightly. Check engine like P2C7A came on. Seems like brakes or transmission momentarily locked up.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the brakes seized, and the service brakes warning light illuminated. Additionally, the contact stated that the vehicle jerked forward. The vehicle was driven to the residence and parked. The contact stated that the vehicle was turned off; however, the service brakes warning light remained illuminated. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was not made aware of the failure. The failure mileage was approximately 34,500.

WHEN DRIVING HOME AFTER PICKING UP MY 2.5-YEAR-OLD AND 6-MONTH-OLD THE BREAKS FELT VERY ODD AND NOT RIGHT. WHEN I APPLIED THEM, IT FELT ROUGH TO APPLY AND THEN HEARD A NASTY SOUND COMING FROM THE REAR OFF TRUCK. I TOOK MY TRUCK IMMEDIATELY TOO THE DEALER AND JUST GOT THE PHONE CALL BACK THAT THE MASTER CYCLINDER FOR MY BRAKE SYSTEM NEEDS TO BE REPLACED. THIS VEHICLE HAS 22,500 MILES ON IT AND IT ALREADY NEEDS SOMETHING FIXED LIKE THIS IS PRETTY SCARY SINCE MY FRIEND JUST HAD IT HAPPEN TO THEM AND THEY GOT IN A MAJOR CAR ACCIDENT. THANK GOD I DIDNT HAVE TO PUT MY FAMILY THROUGH THAT. HAVING A BREAK FAILURE IS SOMETHING NOONE WANTS AND NOT WHEN THE VEHICLE IS PRETTY MUCH BRAND NEW STILL. THE DEALER HAS CONFIRMED THAT THIS IS A VERY RARE CODE IN TERMS THEY USED TO BE HAPPENING. THERE WAS NO WARNING LIGHT OR ANYTHING IT JUST HAPPENED THEN AS I WAS TAKING IT UP TO THE DEALER, I GOT THE SERVICE BRAKE SYSTEM ALERT ON MY DASH.

I bought a loaner 2021 GM Sierra 1500 in Aug. 2021 from Starling Buick GMC, Venice, FL with 1600 miles on it. I used the Sierra to move items from my houses in my trailer from both FL to PA and PA to FL. On each trip The trailer brake controller would go out while driving. The first time it occurred was on a trip from FL to PA, during this trip it happened at least four times. Upon arrival in PA I took it to Kelly Buick GMC in Allentown, PA. They looked over the vehicle, saw there were codes in history indicating an issue with the trailer brake system but could not replicate it or pinpoint what part of the system was faulty. The dealer told me that GM will not fix it if it is in history only if it is currently giving a code. On the return trip back to FL from PA, same thing several times it occurred, took it back to the selling dealer Starling, and they gave me the same speech as Kelly , can't fix it without a current code. Next trip from FL to PA, same thing took it to Kelly again, same response. Back to FL from PA, same thing, Starling gave me the same response, they can't and won't do anything. I told Starling service rep I guess I need to die before you do anything, she was completely indifferent to my comment and backed GM without any regard for my safety. It is sporadic and inconsistent and obviously only occurs when there is a trailer attached. They said it was my trailer so I took it to a trailer mechanic, we tested it on its own and on another vehicle with no problem. The brake controller failed while hauling a trailer potentially allowing a serious if not deadly accident with improper braking capabilities. Even though two dealers in two different states acknowledge there is an issue they refuse to correct it because they can not replicate it. The brake controller lights would go out as you're driving indicating the brake controller is not connected to the trailer and providing a supplemental braking system. 2022 and 2023 have this issue.

All 4 brake rotors are warped according to my local GMC dealership. They also told me all of the inside brake pads are worn twice as much as the outer pads, which in my opinion indicates a manufacturing and/or computer controller issue. Safety is an issue when the inside brake pad wears down to metal while the outers are still over 75% of new thickness. GMC dealer told me they're seeing this on countless Sierra trucks made in the past few years but there is no recall and GMC will not cover it under warranty. First symptom was slight pulsing while braking downhill. 2-3 weeks later my brake pad wear indicator read 82% front, 88% rear. The following day it gave me an error message saying "service brake monitor" so I took it to my GMC dealer which is when they told me my brake pads and rotors all need to be replaced but the truck only had 22800 miles on it at that time. They said it could still be driven and pass inspection. Since then I have contacted GMC about them covering it and I have not made any progress. GMC has had numerous brake issues resulting in recalls in the past 3-6 years but unfortunately this particular issue has not yet reached recall status. I hope this gets resolved before I am forced to pay for brake replacements out of pocket, which nobody should have to do on a vehicle with so little miles on it. The work order invoice I uploaded indicates ""pads at wear limit, both front and rear" but it does not specify what the technician and service advisor told me regarding only the inside pads are worn. However I do have a recording of the service advisor telling me that if needed. You'll also notice that I uploaded a copy of the state inspection done by them that same day which indicates my brake system passed the requirements. Please help.

The contact owns a 2021 GMC Sierra 1500. The contact stated that the grandson was driving in stop-and-go traffic, the braking system suddenly malfunctioned causing the vehicle to crash into the rear of a second vehicle. The grandson was driving approximately 10 MPH when suddenly while pressing the brake pedal to stop the message "brake failure" displayed before the vehicle crashed into the rear of the second vehicle. During the crash, no injuries were reported and a police report was taken at the scene. The vehicle was taken to the local dealer who replaced the master cylinder and brake booster and the failure was remedied. The failure mileage was 21,539

The contact owns a 2021 GMC Sierra 1500. The contact stated that when pulling a trailer with electric brakes with their vehicle, a warning light stating to check the trailer would illuminate on their instrument panel. The warning light would also state that the electric brakes had disconnected and then reconnected shortly after. The failure would occur on a consistent basis. The main control computer system in the center where the radio is located would flash the message that the trailer brake gain not been recalled. The contact contacted the dealer who confirmed that the computer system was known to have an issue due to the interference between the electric brakes and the LAD lights on the vehicle, however, there was no recall. The vehicle had not been repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 21,000.