Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2026 GMC Sierra 1500 owners, lightly cleaned up (personal details are redacted by NHTSA).
5/08/2026: I stopped outside my garage. I then placed the truck in park and exited the vehicle while running. I went inside my garage and several minutes later, heard a crash. The truck had driven forward while unattended, and crashed into the corner of my garage, causing damage to both the building and the truck. Truck indicated it was still in park upon reentry. 5/11/2026 In a separate incident 3 days later, while driving at approximately 50mph, truck engaged in an automatic braking event with no discernible cause. Simply applied what felt like 100% braking for a split second, then released. 5/12/2026: Truck taken to GMC for investigation. No codes in any modules detected. 9/20/2026: Vehicle reports transmission fault, states it should not be driven. 9/21/2026: Towed to GMC dealer. Found codes P17A8 and P189D and diagnostic code 6906361, internal fault within gearshift control module. …
The contact owns a 2026 GMC Sierra 1500. The contact stated that while at a stop light, the engine shut off to save fuel, but after releasing the brake pedal, the engine failed to restart. The contact shifted to park, and the engine restarted. The contact stated that the failure had occurred on several occasions after the fuel saving feature was deactivated. Additionally, the contact stated that the failure had occurred while slowing down and driving over a railroad track and hauling a trailer. The vehicle was taken to the local dealer on several occasions, but the failure was not duplicated. The manufacturer was notified of the failure. The failure mileage was 4,300.
The contact owns a 2026 GMC Sierra 1500. The contact stated that while driving 45 MPH and depressing the accelerator pedal, the vehicle slowed down unexpectedly. The vehicle then lost power while stopped at a traffic light. No warning light was illuminated. The vehicle was turned off and restarted, and the vehicle operated as intended. The vehicle was taken to the dealer, where it was diagnosed and determined that there were metal shavings inside the oil pan and the engine needed to be replaced. The engine was replaced twice. The manufacturer was not notified of the failure. The approximate failure mileage was 3,202.
The contact owns a 2026 GMC Sierra 1500. The contact stated that while driving 35 MPH, the vehicle stalled. Additionally, the wheels locked up, and transmission made a screeching sound. The contact was able to restart vehicle after approximately 5 minutes. The failure was recurrent. The vehicle was towed to the dealer, but the dealer was unable to duplicate the failure. The dealer replaced an unstated module that was damaged during the failure. The manufacturer was contacted by phone and was made aware of the failure. The failure mileage was approximately 6,000.
The contact owns a 2026 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, there was an abnormally loud and rough knocking sound coming from the engine block. The oil pressure decreased to zero, and the engine seized. There was no warning light illuminated before or after the failure. The vehicle was towed to a dealer, where it was diagnosed with a blown engine. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 5,018.
The contact owns a 2026 GMC Sierra 1500. The contact stated that while driving 70 MPH and depressing the accelerator pedal, the vehicle started decelerating unintendedly. The message "Engine Power Reduced" was displayed. A dealer was contacted. The vehicle was taken to a dealer where it was diagnosed and determined that the engine needed to be replaced. The vehicle was repaired. The manufacturer was notified of the failure and opened a case. The approximate failure mileage was 6,028.
The contact owns a 2026 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle made an abnormal sound and failed to accelerate as needed. There was no warning light illuminated. The vehicle was taken to the dealer, who determined that the engine needed to be replaced. The vehicle was not repaired and remained with the dealer. The manufacturer was not made aware of the failure. The failure mileage was approximately 6,000.
The contact owned a 2026 GMC Sierra 1500. The contact stated that while accelerating from a red light at 15 MPH, the vehicle sputtered and shook before finally moving forward. The contact stated the failure was a recurring failure. The contact associated the failure with NHTSA Action Number: EA26005 (ENGINE). The dealer was contacted. The failure mileage was approximately 160.
The contact owns a 2026 GMC SIERRA 1500. The contact stated while driving 40 MPH, the vehicle independently engaged into limp mode. A dealer was contacted. The vehicle was towed to the dealer where it was diagnosed that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was not notified on the failure. The approximate failure mileage was 10,000.
I stopped at a red light in the middle of a 50 mph intersection when the light turned green The engine completely shut off, and it didn't want to turn back on. I was stuck in the middle of the intersection in a very high risk area, putting myself and other drivers at risk. OnStar diagnostics didn't report any issues with the truck. According to their diagnostics, everything should have been running perfectly fine. The motor shut down completely and we weren't able to shift the truck into neutral in order to try to move out of harms way. There was no warning lights or anything before this happened. The first tow truck driver that came by was told that he was there "in order to do a jumpstart" He ran a diagnostic on both of the batteries and said that they were perfectly fine. Another tow truck had to be dispatched since the first wasn't equipped to take the truck. …
NHTSA investigations
Loss of motive power due to engine failure post recall remedy
On January 16, 2026, the Office of Defects Investigation (ODI) opened Recall Query RQ26001. This investigation was opened to assess the remedy effectiveness of Recall 25V-274. ODI has received complaints alleging engine failure in vehicles after the recall remedy had been completed, whether that remedy involved an oil viscosity change or a complete engine replacement.
Engine complaints in other Sierra 1500 years
Frequently asked questions
How common are engine problems on the 2026 GMC Sierra 1500?
NHTSA has 98 complaints about the engine & cooling of the 2026 GMC Sierra 1500, 69% of the model year's 143 complaints.
Is there a recall for 2026 GMC Sierra 1500 engine problems?
No. NHTSA lists no engine & cooling recall for the 2026 GMC Sierra 1500, though it has 2 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2026 GMC Sierra 1500 engine problems start?
Half of the complaints with a recorded mileage happened before about 6,000 miles, and 100% before 25,000 miles.
Is it dangerous?
Owners linked 1 crash, 0 fires and 0 injuries to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.