2021 GMC Sierra problems

“I have repeatedly experienced a noticeable exhaust odor inside the cab while operating the vehicle\. The condition is particularly pronounced during cold weather when the vehicle is idling\. Under these circumstances, the exhaust smell inside the passenger compartment is distinct and concerning\. I have taken the vehicle to two separate General Motors dealerships in an effort to identify and resolve this issue\. On both occasions, I was advised that the vehicle was fine\. Despite these visits, the problem remains unresolved, and I continue to experience exhaust fumes inside the cab under the conditions described above\. My concern is that exhaust gases may be entering the passenger compartment, potentially exposing the driver and passengers to harmful emissions, including carbon monoxide\. Because carbon monoxide cannot be detected by smell, the presence of an exhaust odor does not establish whether carbon monoxide is present or at what concentration\. However, the recurring odor warrants a thorough investigation to determine its source and whether a potentially hazardous condition exists\. I am concerned that the issue may not be adequately identified during…”

“My 2021 GMC 1500 Sierra has the 6.2L motor that has significant known issues with catastrophic engine failure involving the camshaft and lifters. The engine in my truck has suffered the same failure but for some reason my VIN is not included in the recall of nearly 600,000 GMC trucks. I called GMC Customer Service and was told bluntly the recall was VIN specific and I would have to bear the 14,000 dollar repair. This is unacceptable since GMC is under federal investigation for knowingly and negligently manufacturing a flawed motor.”

“The infotainment system inadvertently shuts down and restarts which creates a unsafe situations while using the navigation system, backing up using the backup camera and while trailering. In a 30 mile drive it might do it 10 times and it might do it 30 times and eventually it doesnt restart until the vehicle is shut off. Each time it does it, it starts with the screen locking up which has resulted in me backing into my boat trailer 3 times while backing up to put the trailer on the hitch and numerous near misses with pedestrians and other vehicles in parking lots. Research on the internet indicates it is a known issue across several GMC platforms and has been since 2016. I took my truck to the dealer, they did a software update which was unsuccessful, then they did a global reset, charged me $240.00 and told me it was fixed. It shutdown 2 times before I got out of their parking lot.”

“The contact owns at 2021 GMC Sierra 1500. The contact stated that while driving 60 MPH, the engine was overheating. The message "Reduce Engine Power" was displayed. The contact shifted to neutral to reach the dealer. The contact associated the failure with Special Coverage: N252508341; however, the VIN was not included. The dealer diagnosed the vehicle with coolant control valve failure, and the vehicle was repaired. The manufacturer was made aware of the failure and stated that the cost of the repair was not covered under the special coverage program. The failure mileage was approximately 94,328.”

“The vehicle failed to start. It started after 30 minutes and I was able to drive it home. Then it starts and stalls after multiple attempts. Receiving codes P1177 and UI8A2. Was told that a bulletin exists for this issue on GM vehicles, GM Bulletin 24-NA-139, but I found out that it don't cover my VIN number. This can cause the vehicle to stall or shut off while driving. GM should make this bulletin for all vehicles of certain years who carry this modules.”

“Vehicle Safety Hazard Summary: This complaint concerns an incomplete, non-compliant post-collision structural repair on a 2021 GMC Sierra 1500 (VIN: [XXX]). It has resulted in immediate vehicle tracking failure, dangerous steering drift, and a compromised cabin safety cage following a passenger-side side-impact collision. 1. Severe Suspension and Tracking Misalignment • Electronic Alignment Failure: The post-repair electronic wheel alignment documents a Rear Thrust Angle of 0.17°. General Motors OEM specifications require a maximum allowable thrust angle of 0.10° or less for this 4WD Crew Cab chassis. The system printed a critical warning: "One or more values are not within specification. Tire wear, handling and safety problems may result." • Physical Wheelbase Displacement: Physical cross-measurements confirm a 1.25-inch tracking variance between the rear wheel wells. This proves the solid rear axle has shifted along the leaf springs due to a sheared centering pin or a bent axle/spindle assembly. • Road Hazard Handling: The truck exhibits a severe right-hand steering drift. The driver must hold the steering wheel significantly off-center to prevent the vehicle…”