2020 GMC Sierra service brakes problems

“Lifter failed due to AFM system. Cyl 8 misfire due to oil fouling. The onboard computer got confused and would not release the parking brake until repeated attemtps to release it. 5.3L V8 2020 model year 115250 miles. Isn't this the same problem as the 2021 and newer engines? 8spd transmission. AFM failure. 9k repair.”

“The contact’s mother-in-law owns a 2020 GMC Sierra 1500. The contact stated that while her brother-in-law was starting the vehicle, the brake, service engine, and engine warning lights illuminated and the vehicle failed to start. The contact stated that the failure was associated with NHTSA Action Number: EA25007 (ENGINE, ENGINE, AND ENGINE COOLING) and PE25001 (ENGINE, ENGINE, AND ENGINE COOLING). The vehicle was towed to a local dealer, where it was diagnosed with engine failure. The vehicle was not repaired. The owner was scheduled to meet with the dealer to discuss the issue. The manufacturer was contacted and confirmed that there were no open recalls on the VIN related to the failure. The failure mileage was approximately 45,000.”

“The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle decelerated to 30 MPH. The check engine warning light was illuminated. The vehicle was taken to a local dealer, where it was diagnosed, and determined that the timing belt needed to be replaced. The part was on back order. The vehicle was not repaired. The contact stated the vehicle previously experienced brake failure, sensor failure, and glow plug failure. The manufacturer was contacted, but no assistance was provided. The BBB referred the contact to the NHTSA Hotline to report the failure. The failure mileage was approximately 80,000.”

“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.”

“First my torque converter went out, no warning lights only shaking wehn shifting, I got it replaced already it cost me 2400 Second Warning light service for Brakes, Traction and power steering come on and off. And sometimes truck doesn't brake well and steering wheel feels hard to drive, it has happened while on expressway with family. Third Engine oil low Add oil warning sign comes up alot and I have to add oil, engine has a rough idle now, also when I turn truck on smoke comes out while having a rough idle, recently it started knocking, I haven't moved the truck since than”

“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.”