2021 GMC Yukon brake problems

SERVICE BRAKES

As I was driving, the vehicle's air conditioning suddenly began blowing warm/hot air. Moments later, the check engine light and all electronic service stability lights illuminated on the dashboard. Simultaneously, the vehicle suffered a complete loss of electronic brake assist, resulting in an extremely hard brake pedal and a severe reduction in braking power. The vehicle also displayed a "No Drive Mode Available" message. Third-party diagnostic scanning revealed network power codes U3018, U3505, P00FF, and P0700, indicating a total loss of power to the Body Control Module (BCM). This is the second life-threatening incident with this vehicle I have experienced following a previous highway engine stall due to engine recall. The vehicle was towed to a GM dealership for diagnostic and emergency electrical repairs.

NHTSA complaint #11757731 — an unverified report by a vehicle owner.

SERVICE BRAKES

On July 28, 2026, while traveling on vacation with my family, our vehicle experienced a catastrophic engine failure. There were warning lights displayed for 30 seconds prior to the engine failure. On July 23, 2026, one day before taking the vehicle to the dealership, the following warning indicators appeared on the dashboard and then disappeared: “Service ESC,” “Service Traction Control,” and a flashing engine light. We took the vehicle to the dealership on July 24, 2026, because we wanted to be proactive and ensure that the vehicle was safe to operate. The dealership inspected the vehicle but reported that no diagnostic trouble codes were identified and no issue was found. We picked the vehicle up from the dealership on the evening of July 27, 2026. On July 28, 2026, while traveling on the highway approximately 2.5 hours from home, the same warning messages appeared on the dashboard again. Because we were traveling at highway speeds and vehicle speed management was becoming an issue, I immediately exited the highway and stopped in a parking area. I placed the vehicle in park, at which point the engine began idling extremely rough. I could feel the vehicle shaking while sitting in the driver's seat. I exited the vehicle to open the hood, but before I was able to do so, I noticed gray smoke coming from the exhaust. We located a GMC dealership approximately two miles away. Because of the vehicle's condition, we drove there slowly on the frontage road at approximately 15 mph and dropped the vehicle off for diagnostic inspection. The GMC dealership subsequently diagnosed the vehicle with catastrophic engine failure and recommended that the engine be replaced. The vehicle remains at the dealership and is available for inspection.We made a reasonable effort to have the vehicle inspected before our trip because we were concerned about the warning indicators and wanted to ensure that the vehicle was safe to travel.

NHTSA complaint #11756194 — an unverified report by a vehicle owner.

SERVICE BRAKES

The contact owns a 2021 GMC Yukon. The contact stated while driving at an undisclosed speed, the engine seized. The brake pad sensor warning light illuminated. In addition, the contact stated that the vehicle continued to roll forward. The contact was able to drive the vehicle to the shoulder of the road. The contact stated while attempting to restart the vehicle, the vehicle failed to start. The contact stated that a nearby driver assisted by providing a jumpstart. The vehicle was driven to the residence. The vehicle was then taken to an independent mechanic where it was diagnosed with alternator failure. The contact stated that the vehicle was previously taken to two independent mechanics, and the vehicle was diagnosed with alternator failure. The dealer was made aware of the failure. The contact was informed that the failure was a known failure with similar vehicles. The manufacturer was made aware of the failure with the alternator and the brake pad sensor. The contact was informed that the repairs were not covered under warranty or recall. The failure mileage was approximately 95,000.

NHTSA complaint #11698010 — an unverified report by a vehicle owner.

SERVICE BRAKES

The component that failed was the Camshaft and Lifters in the Engine - My safety and others was put at risk because while going 45mph, I suddenly lost forward moving power and couldn't go faster than 35 - braking power was sketchy and only responsive when pumped. - I received the following errors on my dash "Service ESC" "Service Traction Control", Reduced Acceleration Drive with Care", "Forward Collision System Unavailable", "Service Emission System" the vehicle would shudder violently- this problem has been confirmed and corrected at a huge expense (see bill) -

NHTSA complaint #11647336 — an unverified report by a vehicle owner.

SERVICE BRAKES

This GMC Yukon underwent an over the air update in remote Wyoming and was almost undriveable due to steering problems and brake malfunction. Also engine and transmission problems. It has been awaiting repair, but I have been informed that no fix is available because of transmission defect. No parts available We were nearly stranded.

NHTSA complaint #11545764 — an unverified report by a vehicle owner.

SERVICE BRAKES, AIR:ANTILOCK:ABS WARNING LIGHT

The contact owns a 2021 GMC Yukon. The contact stated that while driving at an undisclosed speed, the odometer was inoperable. There was an abnormal odor of fuel while starting the vehicle. The parking brake and TPMS warning lights were illuminated and flashing. The parking brake was inoperable. Additionally, the seat belts were inoperable. The contact stated that there was a cut in brake line. The vehicle was taken to the local dealer where it was diagnosed and determined that the brake master cylinder needed to be replaced. The vehicle was repaired but the failure persisted. The manufacturer was contacted but provided no additional assistance. The failure mileage was approximately 60,000.

NHTSA complaint #11526929 — an unverified report by a vehicle owner.

SERVICE BRAKES

I own a 2021 GMC Yukon Denali that had TOTAL BRAKE FALIURE last Tuesday. I had it towed to a local GMC dealer and are repairing it under warranty. I was lucky to be on a back road when my brakes went out. I had no warning lights come on prior to hitting the brake pedal and was able to coast to a stop on the shoulder When I applied the brakes, the pedal went to the floor and did nothing. You can't stop the car with the parking brake because it is electric. My concern is what if I was on a busy road when this happened or what if this happens to a family in traffic they could be seriously hurt or worse yet killed. I do have good photos of my instrument panel with all of the warning lights coming on after I tried to stop. In good conscience feel that I have to at least try and report this to GM, the state and anyone else that will listen. If nothing comes of this at least I tried and just hope no one gets hurt if this happens again. My wife refuses to ride in that vehicle until I have solid answers. The dealer said they will have my car repaired this week and are replacing the master cylinder and ECS This is fine but why did it happen and how can I be sure it won't happen again? I believe in GM and have a 2023 Yukon Denali on order. I would hope that after 3 years of this model they have most of the little quirks worked out. A rep from GM did contact me and at first was talking about buying my car back but changed that today. My case number is 9-8497380349 . The problem is I have no idea when my new car is coming in our should I just cancel it and find something else. In my opinion this is a very serious problem.

NHTSA complaint #11491401 — an unverified report by a vehicle owner.

SERVICE BRAKES

On Friday October 22, 2021 around 7:20am as I was driving my children to school I was driving around 40 mph when suddenly I received an alert on the dashboard saying “brake system fail”, I then proceeded to brake to make sure my breaks were working when I noticed they did not work. I then started pumping the gas pedal repeatedly to make the vehicle stop. My car was not stopping and my children and I panicked and started crying. As I was getting closer to a vehicle and ready to crash I swerved the vehicle to the right where it was just an empty lot. I continue to press and pump the brakes until the vehicle came to a complete stop. I took pictures of the dash board once the vehicle was completely off. My Vehicle was towed to my house shortly after. I refuse to drive that vehicle after the terrible experience that jeopardize the life of my children and myself. We have suffered emotional distress.

NHTSA complaint #11438090 — an unverified report by a vehicle owner.

SERVICE BRAKES

TRAVELLING DOWN THE HIGHWAY 69 MPH WITH MY WIFE AND THREE SMALL CHILDREN WHEN THE DASH FLASHED MULTIPLE ERROR CODES, ENGINE SPEED LIMITED TO 62 MPH, AND BRAKES ESSENTIALLY WENT OUT. WAS ABLE TO GET SAFELY STOPPED. CONTACTED DEALERSHIP AND THEY ADVISED SHUTTING IT OFF FOR 20 MIN AND IT WOULD "RESET". IT DID NOT RESET AND WE REFUSED TO DRIVE IT IN SUCH UNSAFE CIRCUMSTANCES WITHOUT ADEQUATE BRAKE FUNCTION ETC. GMC ROADSIDE ASSISTANCE CAME AND TOWED IT AWAY. COULD HAVE RESULTED IN MUCH WORSE OUTCOMES AND WE ARE THANKFUL NO ONE WAS INJURED. VERY NERVOUS TO DRIVE IT AGAIN AFTER WE GET IT BACK, NOT KNOWING IF IT WILL MALFUNCTION AGAIN.

NHTSA complaint #11406358 — an unverified report by a vehicle owner.

SERVICE BRAKES

DRIVING APPROX. 62 MPH ON A HIGHWAY, WENT TO SLOW DOWN AND UNABLE TO BRAKE, UPON PUSHING DOWN ON THE BREAK THERE WAS RESISTANCE, AFTER PUMPING THE BREAKS MULTIPLE TIMES I WAS EVENTUALLY ABLE TO SLOW DOWN WITH A LOT OF FORCE. MESSAGES ON DASHBOARD READ "BRAKE SYSTEM FAILURE" "62 MAX SPEED ESC, SERVICE ESC, SERVICE TRAILER BREAK SYSTEM, AND FORWARD COLLISION SYSTEM UNAVAILABLE." ABS, ESC AND CHECK ENGINE LIGHT ALL ILLUMINATED ON DASH SCREEN.

NHTSA complaint #11402695 — an unverified report by a vehicle owner.