# 2026 GMC SIERRA 1500 — ELECTRICAL SYSTEM
> NHTSA complaint `2254735` · 2026-10-08 · General Motors, LLC
## Severity
- **Deaths:** 0
- **Injured:** 0
- **Fire:** No
- **Crash:** Yes
- **Police report:** No
- **Medical attention:** No
- **Vehicle towed:** Yes
## Vehicle
- **Make:** GMC
- **Model:** SIERRA 1500
- **Year:** 2026
- **Manufacturer:** General Motors, LLC
- **Component:** ELECTRICAL SYSTEM
- **Speed:** 5 mph
## Narrative
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.  Requested GMC pay for damage resulting from collision, as clearly the unattended driving appeared related to gearshift control, but was refused.  GMC stated that unattended driving was not possible and did not result from the detected failures.
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*Source: [NHTSA ODI](https://www-odi.nhtsa.dot.gov/downloads/) · MORVS · CC0 1.0*