2021 Chevrolet Tahoe electrical system problems

“While traveling at highway speeds, the vehicle experienced an instantaneous, simultaneous, and total failure of both the electronic eBoost braking system and the electronic power steering assist. The dashboard flashed multiple critical system malfunction notifications with zero prior warning. When attempting to slow down, the brake pedal sank completely to the floor with zero mechanical resistance and provided absolutely no braking response. Primary control of the heavy SUV was lost, forcing a dangerous maneuver across three highway lanes to avoid a high-speed collision. The vehicle is currently at a dealership due to a Fuel Pump Power Control Module Recall. Because this module interfaces with the high-speed electronic data network (CAN bus), its failure mode appears linked directly to the catastrophic communication drop that disabled the eBoost brakes and steering. This failure aligns with the mechanical faults documented under federal safety recalls 21V-455 and 21V-579, as well as the active NHTSA Engineering Analysis EA26006 investigating GM eBoost system failures. The defect completely stripped the vehicle of its primary safety functions without warning.”

“There are thousands of people across social media and internet websites with the same exact problem they are having with 2021 chevy tahoe. There has also been multiple recalls for the same problem but seems it was not issued for all the vehicles that has this default. The Brake service light first came on the dash along with service esc, max speed limited to 43, service brake monitor system. It was taken to multiple shops for a diagnostic including Jim Hudson Chevy and all of them said how this is an ongoing issue with 2021 tahoes. No one knows the exact problem or cause. The dealership said it’s probably the brake control module, because that’s what the issue was all of the other times they had this occur.”

“While at a drive thru, my 2021 Chevy Tahoe High Country experienced a total failure with no advance warning where the engine shut down and would not restart despite what appeared to be good electrical power. We tried to jump start the vehicle with both another vehicle as well as a AAA power pack with no luck. The vehicle was not movable and had to be towed using a lift truck to the dealer. The dealer performed an analysis, reproduced the problem, and determined that the engine failed due to a spun bearing despite no documented codes from the analysis. In performing research, this failure appears identical to NHTSA Campaign 25V274 / GM number N252494000 however the car has been deemed to not be covered with mileage at 139,300.”

“During highway driving, alert on dashboard stated “electrical system failing enter idle mode”. Tahoe slowed down and then engine began knocking right as it shut off resulting in needing to coast to the shoulder of the highway safely since engine was off. Towed to dealership and then they came back saying needed a new battery, new alternator belt, pulley and water compartment. After those installed, additional call was made indicating the engine needed a full replacement as it keeps overheating despite no sensor alerts and codes are being tripped. Here we are asked to pay 16K for new engine install and unable to fix.”

“The contact owns a 2021 Chevrolet Tahoe. The contact stated that while driving at an undisclosed speed, there was a breach in communication with the OnStar system. The contact believed that the brakes failed, and several other safety systems became inoperable due to a failure with the OnStar system. The dealer was notified of the failure, but the vehicle was not diagnosed or repaired. The manufacturer was notified of the issue. The failure mileage was 114,000.”

“Since March of 2025 I have identified a critical safety defect with my vehicle. When driving and without warning, the vehicle unexpectedly shifts to neutral, experiences a loss of propulsion, and the engine shuts off. This has occurred multiple times in which I narrowly escaped collisions with other vehicles or objects. If this would occur at a high rate of speed, it would certainly result in serious accident including possible fatality. I have experienced three near-accident scenarios when I had children in the vehicle. I have worked with Classic Chevrolet in Sugar Land, Texas who has made six attempts at repair. They have each time found a different component attribute to an error code and replaced that part. After each visit they tell me that the car is fixed and safe to drive. They have never been able to provide a clear explanation as to why I am experience this reoccurring issue, but attribute it to a different part each time. Within 5 days to 2 months, the incident repeats. I have recent video of the incident that I can share. Chevrolet Customer Care has been minimized my concern and informs me that their Service staff has found the vehicle to be fully…”