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2020 GMC Sierra Denali
Limited data: few reports on file, read the verdict loosely
Too few owner complaints are on file to affirm this car. Treat it as unproven, not endorsed, and lean hard on a professional pre-purchase inspection.
9 owner complaints · 0 recalls · data verified July 19, 2026 · source: NHTSA
What the record shows so far
Only 9 owner complaints on file for this exact model year, too few to judge long-term reliability. Treat this as unproven, not endorsed, and lean on a professional inspection.
Score breakdown, by factor
Full methodology →Complaints filed per year
Fading = early teething worked out. Climbing = problems aging in.
How it crashes
NHTSA’s own crash tests, separate from the reliability score above.
NHTSA hasn’t published a crash-test rating for this model year. That’s common for lower-volume or older models. It doesn’t mean the car is unsafe, just that this program hasn’t tested it.
Source: nhtsa.gov/ratings. Star ratings compare vehicles within the same class and size, not across every car on the road.
The road ahead
What breaks on a 2020 GMC Sierra Denali, plotted where owners report it happening.
Also reported (mileage varies): Engine (5)
Mileage medians come from owners who mentioned an odometer reading in their NHTSA complaint, a rough guide, not a schedule.
Engine
56%5 complaints · 1 in the last 2 years
“KNOCKING COMING FROM ENGINE - NOTICEABLE UNNECESSARY NOISE IN WHICH DEALER CAN NOT FIX THE PROBLEM”
Brakes
22%2 complaints
“BRAKES SQUEAK. STARTED ABOUT 3000 MILES. I HAVE COMPLAINED TO DEALER SEVERAL TIMES.”
Engine & cooling
11%1 complaints · 1 in the last 2 years
“The contact owns a 2020 GMC Sierra Denali. The contact stated that while stopped at a traffic light with the brake pedal depressed, the vehicle shut off unexpectedly. …”
Driver assistance
11%1 complaints
“The contact owns a 2020 GMC Sierra Denali. The contact stated while driving 75 MPH, the Adaptive Cruise Control feature became inoperable. The contact stated that when…”
Check it against this car’s mileage
Type the odometer reading on the actual car you’re looking at to see which of these problem areas owners tend to report before it, around it, or after it.
Too few owners named a mileage on this model to place issues against an odometer yet.
Recalls (0)
No recall campaigns on file for this model year.
Questions to ask the seller
Questions worth asking the seller of this GMC before you buy, drawn from its public record:
- Owners of this model report engine problems more than anything else. Has this car shown any engine symptoms, and are there repair records for it?
- Has this car been in any accident or had any structural, airbag, or flood-related repair? Do you have a clean title and a recent history report (Carfax / AutoCheck)?
- How many owners has it had, do you have the maintenance records, and why are you selling it?
- Are you open to me having an independent mechanic inspect it before we settle on a price?
Before you hand over money
Check the VIN for open recalls
NHTSA’s free lookup shows whether this exact car had its recall remedies completed.
Free NHTSA VIN check ↗Get a pre-purchase inspection
A $150 to $250 independent inspection of this exact 2020 GMC SIERRA DENALI beats every score on the internet, including ours.
What to ask forNot set on the 2020? See how every Sierra Denali model year scores →
Cross-shopping? Compare the 2020 GMC Sierra Denali against another car →
What owners say
Real owners of this exact model-year, shown separately from the NHTSA score. If they disagree, that’s worth knowing.