2020 GMC Sierra Denali Problems
- Complaints
- 11filed with NHTSA
- Median mileage
- 20,000miles, 9 complaints with mileage
- Recalls
- 0campaigns on record
- Trend
- Not enough dataFewer than 15 complaints, too few for a reliable trend.
Sources: NHTSA records for the 2020 GMC Sierra Denali (complaints, recalls, investigations). Report an error
NHTSA recorded 11 consumer complaints for the 2020 GMC Sierra Denali. The part named most often is engine, with 6 complaints (55% of the total), followed by brakes (2) and forward collision avoidance (2). 9 of the complaints include a mileage, and 67% of those were filed for vehicles with under 50,000 miles; the median is 20,000 miles. NHTSA lists 0 recall campaigns and 359 technical service bulletins for this model year. Engine complaints overlap with 38 technical service bulletins filed under the same part. Brakes complaints overlap with 9 technical service bulletins filed under the same part.
This model year has fewer than 25 complaints on record, so the numbers below can change a lot with a few new reports.
Which parts are reported most
Complaints can name more than one part, so the counts add up to more than the total. Select a part to see its complaints, recalls and bulletins.
- Engine6 55%
- Brakes2 18%
- Electrical system1 9.1%
- Engine cooling1 9.1%
Example complaints
Engine: “I noticed several spots of oil on my driveway, I then inspected the underside of the engine (l5p) and noticed oil dripping from several bolts and lines. My vehicle, a 2020 2500hd denali diesel, has only 2,200 miles on it from normal highway driving.”
NHTSA complaint #11363419, filed 2020-10, 2,200 milesBrakes: “Two issues broken valve spring caused engine to shut down, second service brake, brake failure light, service ESC, service trailer brake messages causing brake failure”
NHTSA complaint #11367036, filed 2020-10, 350 milesForward collision avoidance: “The contact owns a 2020 GMC Sierra Denali. The contact stated that while driving with Adaptive Cruise Control set to 55 MPH, the vehicle suddenly accelerated. The contact depressed the brake pedal to disengage the Adaptive Cruise Control settings, preventing the vehicle from crashing into the vehicle ahead. The contact stated that the failure had occurred while the Adaptive Cruise Control was engaged. The approximate failure mileage was 99,000.”
NHTSA complaint #11764047, filed 2026-09, 99,000 milesElectrical system: “The contact owns a 2020 GMC Sierra Denali. The contact stated while driving 65 MPH at night, the vehicle stalled and the “Shift to Neutral and Restart Vehicle” message was displayed. The contact was unable to restart the vehicle and was unable to visibly see the roadway. The contact was able to park on the side of the road. The vehicle was not drivable. The contact towed the vehicle to his residence, and then to the local dealer the next day, where the vehicle was diagnosed with needing the starter to be replaced. The vehicle was repaired. The manufacturer had not been informed of the failure. …”
NHTSA complaint #11519126, filed 2023-04Mileage when problems were reported
67% of the 9 complaints with a mileage were filed for vehicles with under 50,000 miles; the middle half falls between 3,000 and 98,500 miles.
Complaints by year filed
Fewer than 15 complaints, too few for a reliable trend.
Recalls and investigations
NHTSA lists no recall campaigns for the 2020 GMC Sierra Denali in the data used here. A recall can apply to some vehicles of a model year and not others, so check a specific vehicle by VIN at nhtsa.gov/recalls.
Technical service bulletins
TSBs are manufacturer notes to dealers about known repair procedures. They are not recalls and do not by themselves mean a vehicle has a fault. 359 on record; the latest 10 are shown.
- 11037555Sep 26, 2026Other or unknown. This PI provides Diagnostics tips on how the LIN bus works and how to diagnosis it.
- 11037253Sep 4, 2026Other or unknown. This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.
- 11035340Jul 21, 2026Other or unknown. PI to help diagnose A/C concern
- 11030974Apr 1, 2026Other or unknown. This preliminary information communicates information about how to determine if a wheel and tires size change is available.
- 11030092Mar 9, 2026Other or unknown. This Preliminary information communicates the steps on how to save a GDS2 Session Log and upload to a Technical Assistance Case in CX Connect.
- 11030091Mar 9, 2026Other or unknown. This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.
- 11029950Mar 2, 2026Other or unknown. This Preliminary information communicates to the field on how to diagnosis a GPS issue with the Telematic module with no DTC'ss
- 11027697Jan 16, 2026Other or unknown. This Preliminary information communicates to the field on how to diagnosis a GPS issue with the Telematic module with no DTC's
- 11027701Jan 14, 2026Other or unknown. This PI advised dealer technicians of possible causes of diesel fuel contamination in gasoline powered vehicles and advises of warranty direction.
- 11027601Jan 8, 2026Other or unknown. This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.
Other model years of the GMC Sierra Denali
| Year | Complaints | Median mi | Recalls | Crash ★ | MPG | Score (50 = typical) | Trend |
|---|---|---|---|---|---|---|---|
| 2020 | 11 | 20,000 | 0 | — | — | — | Not enough data |
| 2019 | 26 | 5,269 | 0 | — | — | 77 · More | Falling |
| 2018 | 17 | 28,000 | 0 | — | — | — | Falling |
| 2017 | 15 | 60,000 | 0 | — | — | — | Falling |
| 2016 | 30 | 48,000 | 0 | — | — | 50 · Typical | Falling |
| 2015 | 22 | 47,800 | 0 | — | — | — | Stable |
| 2014 | 14 | 59,496 | 0 | — | — | — | Not enough data |
| 2013 | 8 | 70,000 | 0 | — | — | — | Not enough data |
| 2012 | 10 | 50,000 | 0 | — | — | — | Not enough data |
| 2011 | 28 | 65,000 | 0 | — | — | 0 · Fewer | Falling |
| 2010 | 10 | 45,284 | 0 | — | — | — | Not enough data |
| 2009 | 7 | 94,000 | 0 | — | — | — | Not enough data |
| 2008 | 18 | 58,000 | 0 | — | — | — | Stable |
| 2006 | 5 | 61,000 | 0 | — | — | — | Not enough data |
| 2004 | 11 | 44,000 | 0 | — | — | — | Not enough data |
| 2002 | 13 | 79,315 | 0 | — | 12 | — | Not enough data |
All GMC Sierra Denali model years · Best and worst years by complaints
Frequently asked questions
How many NHTSA complaints does the 2020 GMC Sierra Denali have?
NHTSA recorded 11 consumer complaints for the 2020 GMC Sierra Denali as of Oct 30, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
What part of the 2020 GMC Sierra Denali is reported most often?
Engine is named most often, in 6 complaints (55% of the total), followed by brakes with 2.
Has the 2020 GMC Sierra Denali been recalled?
NHTSA lists no recall campaigns for this model year in the data used here. To check a specific vehicle, enter its VIN at nhtsa.gov/recalls.
At what mileage are problems with the 2020 GMC Sierra Denali reported?
Among the 9 complaints that include a mileage, the median is 20,000 miles and the middle half falls between 3,000 and 98,500 miles; 67% were filed for vehicles with under 50,000 miles.
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 30, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
Complaint counts come from NHTSA’s public complaint database; we count each complaint once. The source records for this vehicle are on nhtsa.gov. Scores and trends are our own summaries of that data, described in the methodology. This page is not legal, safety or repair advice: for a specific vehicle, check its VIN at nhtsa.gov/recalls and ask a qualified mechanic. See an error? Tell us.