*Median odometer reading when the problem happened, where owners gave one. One complaint can name several problem areas.
Unknown or other
Rear sliding window leak. Water stains on head liner unsure of addition damage.
Oct 15, 2026Power train
The contact owns a 2020 GMC Sierra 2500. The contact stated that while stopped at a traffic light and making a left turn at approximately 20 MPH, the transmission failed. The vehicle was unable to exceed 10 MPH. The check engine warning light illuminated, and a dinging sound was heard following the incident. The vehicle shifted erratically, jumped gears, and made unusual noises. The contact associated the failure with NHTSA Campaign Number: 24V797000 (Power Train). The vehicle was towed to the dealer for diagnosis. The dealer confirmed an internal transmission failure and clutch lockup, with DTC P2732. Additionally, the transmission fluid was burnt and contained metal shavings. The dealer…
Oct 6, 2026 · 107,000 milesStructure › Body
My rear spoiler roof area leaks. This is something GM knows about and has sent out memos to dealers. To fix this itâs around $1000. I think GM should fix a problem they have been well aware of for sometime.
Oct 1, 2024Power train
A dealer "fixed" the P20EE code on this date, then the code came back a week later. Same dealer said they don't have qualified diesel technician, took vehicle to a 2nd dealer 9/22/2025, unable to determine cause of code. On 6/18/2026 same P20EE code came on again, took to dealer, dealer able to perform repairs on 7/30/2026 after ordering the correct parts. No on 9/23/2026 P20EE code is back.
Aug 1, 2025Vehicle speed control
While driving vehicle flashed engine power reduction signal and then the emergency brake automatic feature came on abruptly. Fortunately, I had been able to slow down after the reduced power, but if I wouldn't have quickly reacted to that, I think the emergency brake system would have caused a safety issue. Now. The vehicle is incapacitated. There were two recalls that describe this exact situation on the same year and model of truck, but my VIN number did not fall. Under that recall. The recall was for the sensor and then the second recall was because the first recall didn't correctly fix it. But the details of the faulty sensor are exactly what happened to my truck. So it sounds to me…
Sep 17, 2026Electrical system
When I try to start my truck it comes up as service trailer brake control module and it has caused my truck battery to drain so I cant even crank my truck up.
Aug 24, 2026Engine and engine cooling
The contact owns a 2020 GMC Sierra 2500. The contact stated that the check engine warning light was illuminated, and the message "Reduced Power" was displayed. The vehicle was taken to the dealer, where the turbo actuator and wastegate position sensor A-circuit were replaced; however, the failure persisted. The vehicle was taken back to the dealer, and the contact was advised that another diagnostic test was needed. The contact declined to pay for the diagnostic test. The vehicle was taken to a retired GM mechanic, who diagnosed the vehicle with turbo charger failure. The vehicle was not repaired due to the cost. The manufacturer was notified of the failure, but no assistance was provided.…
May 30, 2025 · 100,000 milesPower train
While driving down a highway doing between 45 and 55 mph the transmission suddenly and completely faulted causing the truck to come to a complete stop. Just enough power to get to the shoulder luckily. The transmission had basically completely blown out, fluid everywhere. The insurance company did not find any comprehensive damage. The entire transmission needs to be replaced. There were no indicators showing any problems, no alerts, no warning whatsoever. Mechanics said there was a lot of metal coming out of the transmission. The truck is currently in a mechanic shop awaiting the new transmission, so at this time it is available for inspection. The safety issue here is that it happened on…
Feb 18, 2026
Owner complaints are submitted to NHTSA by the public and are not verified. Shown as filed (NHTSA removes personal details); long reports are shortened.