2020 GMC Sierra 3500 Engine Problems
- Complaints
- 6about this part
- Share
- 12%of 51 total for the year
- Median mileage
- 19,000miles
- Trend
- Not enough dataFewer than 15 complaints, too few for a reliable trend.
NHTSA recorded 6 complaints about the engine of the 2020 GMC Sierra 3500, 12% of the 51 complaints for this model year. Where a mileage was given, the median is 19,000 miles. 1 a fire, according to the filers.
Fewer than 15 complaints name this part, so treat the figures as a rough indication only.
Example complaints
Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.
“The computer lights up the dash reducing power and turning off power to trailer brakes. This has almost caused an accident on several occasions . It happens a couple of times per trips. This vehicle has been in the shop a couple of times per month since it was put into service. Glenn Polk Chevrolet has worked on it each time and the problem is still there. This truck has also had several injector issues. There is an open case with this vehicle with General Motors with no resolution. I have filled out forms on each of my 2020 GMC's 3500's.”
NHTSA complaint #11418621, filed 2021-05“the engine seized at 65mph. available for inspection. was left stranded in a limited access area with no cell service. there was no warning, the engine just stopped at highway speed and would not restart. the problem was confirmed by an independent service center. they couldnt identify which component had failed without a costly teardown. occurred at 112,000 miles, past the 100,000 mile powertrain warranty.”
NHTSA complaint #11691992, filed 2025-10“The contact owns a 2020 GMC Sierra 3500. The contact stated while driving approximately 60 MPH, the vehicle jerked, lost motive power, and almost stopped unintendedly. There was no warning light illuminated. The contact was able to pull into a parking lot, where the vehicle shut off. The contact stated that while attempting to restart the vehicle, the diagnostic trouble code: P129F was displayed, and the vehicle failed to restart. The vehicle was towed to the residence. …”
NHTSA complaint #11627460, filed 2024-11, 19,000 milesRelated service bulletins
- 11024330Sep 6, 2025This technical bulletin provides a procedure to replace the camshaft actuator magnet to correct customer concerns of engine related shudder.
- 11026017Jun 5, 2025This service bulletin provides information on replacing the intake manifold when the engine is replaced after severe internal engine damage.
- 11024486May 16, 2025This bulletin advises the tech to inspect deeper into what may be to main cause of an engine failure.
- 11024485May 15, 2025The service bulletin advises the tech of a normal transmission shift condition and the delay in throttle response when the throttle plate is opened rapidly and advises the…
- 11020254May 7, 2025This service bulletin provides information to dealership personnel for new vehicles with less than 1,000 miles that may not pass California smog inspection or smog inspection in…
- 11019503Apr 18, 2025This warranty administration bulletin provides policy information on vehicles outside of a California Emissions State who move to and register their vehicle in a California…
- 11017263Mar 25, 2025This bulletin advises the technician to flush the cooling system multiple times if oil has been found in the cooling system and replace the parts that may be contaminated due to…
- 11016945Mar 13, 2025This technical bulletin provides repair information to correct a customer concern of Evaporative DTCs P0442, P0446, P0455 or P0449, Caused by Dust Intrusion into the Evaporative…
- 11016942Mar 4, 2025This bulletin advises the technician to flush the cooling system multiple times if oil has been found in the cooling system and replace the parts that may be contaminated due to…
- 11014640Feb 28, 2025This Preliminary information communicates that some customers may comment that after an auto-stop event the engine does not restart and to inspect the engine ground strap…
Engine: other model years
| Year | Complaints | Share of year |
|---|---|---|
| 2025 | 2 | 12% |
| 2024 | 8 | 16% |
| 2023 | 3 | 11% |
| 2022 | 3 | 9% |
| 2021 | 3 | 15% |
| 2020 | 6 | 12% |
| 2019 | 2 | 15% |
| 2018 | 1 | 7% |
| 2017 | 2 | 15% |
| 2016 | 5 | 26% |
| 2015 | 4 | 13% |
| 2014 | 1 | 14% |
| 2013 | 2 | 14% |
| 2012 | 3 | 33% |
| 2011 | 1 | 5% |
| 2008 | 1 | 4% |
| 2007 | 2 | 13% |
| 2005 | 1 | 4% |
| 2002 | 1 | 5% |
| 2001 | 2 | 6% |
Other parts of the 2020 GMC Sierra 3500
19 complaintsElectrical system
9 complaintsBrakes
7 complaintsFuel system
6 complaintsOther or unknown
6 complaintsBody and structure
5 complaintsTires
4 complaintsVisibility (wipers, defrost, mirrors)
2 complaintsAir bags
1 complaintsEngine cooling
1 complaintsExterior lighting
1 complaintsForward collision avoidance
1 complaints
← All problems reported for the 2020 GMC Sierra 3500
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 29, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology