2020 GMC Sierra 1500 vehicle speed control problems
10 owner complaints filed with NHTSA name the vehicle speed control on the 2020 GMC Sierra 1500 — 2% of all complaints for this model year.
What owners report
“The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle decelerated to 30 MPH. The check engine warning light was illuminated. The vehicle was taken to a local dealer, where it was diagnosed, and determined that the timing belt needed to…”
filed Apr 29, 2026
“The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at 65 MPH, the DEF tank failed. The vehicle went into three phases of LIMP Mode and the vehicle unexpectedly decelerated while driving. The DEF system service message was displayed. The vehicle was taken to the local…”
filed Mar 23, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Vehicle Speed Control problems in other Sierra 1500 years
| Year | Reports | Share |
|---|---|---|
| 2026 Sierra 1500 | 2 | 3% |
| 2025 Sierra 1500 | 5 | 5% |
| 2024 Sierra 1500 | 10 | 3% |
| 2023 Sierra 1500 | 9 | 2% |
| 2022 Sierra 1500 | 5 | 1% |
| 2021 Sierra 1500 | 5 | 1% |
| 2019 Sierra 1500 | 10 | 2% |
| 2018 Sierra 1500 | 6 | 2% |
| 2017 Sierra 1500 | 11 | 3% |
| 2016 Sierra 1500 | 4 | 1% |
| 2015 Sierra 1500 | 7 | 1% |
| 2014 Sierra 1500 | 12 | 2% |
Other reported problem areas on the 2020 GMC Sierra 1500
Counts are unique NHTSA complaints naming this component group. Complaints are unverified owner reports; mileage is computed only from complaints that included a usable odometer reading.