The Lemon Index2020 GMC Sierra.
The 2020 GMC Sierra is better than average by owner complaints: 179 complaints in its first 3 years and a Lemon Index of 75, where 100 is the average car. Owners complain most about electrical, it has 16 recalls, and it gets 16 to 26 mpg combined. The best GMC Sierra year is 2010.
Before you buy. What matters most for this car.
How serious. Out of 620 owner complaints, owners reported:
Every GMC Sierra year. 2020 is highlighted. Lower is better.
What owners complain about most. From owner complaints to the government.
Share of this year's owner complaints filed with NHTSA, not the share of cars that break. One complaint can name more than one area.
When owners reported problems. From owner complaints to the government.
Most owners who filed a complaint with NHTSA had 4K to 87K miles on the car (172 complaints listed the miles). This shows when people who had a problem reported it, not the odds that your car will have it.
- engine complaints mostly came at 5K–80K miles
- transmission & drivetrain complaints mostly came at 41K–113K miles
- electrical complaints mostly came at 0K–38K miles
Recalls 16
- transmission & drivetrain 2026
The transmission control valve may fail and cause the rear wheels to lock up.
- transmission & drivetrain 2024
The transmission control valve may fail and cause the rear wheels to lock-up.
- latches/locks/linkages 2024
The tailgate's electronic gate-release switch may short circuit due to water intrusion, which can result in the tailgate inadvertently unlatching while the vehicle is in park.
Show all 16 recalls
- tires 2021
The 17" spare tire provided with the vehicle is not compatible for use with the accessory wheels, which can cause the anti-lock brake system (ABS) to not function properly under certain conditions.
- tires 2021
Operating the spare tire with other 20" or 18" tires can prevent the Anti-Lock Braking System (ABS) from engaging.
- tires 2021
The affected tires were cured for too long during production.
- seat belts 2020
The seat belt brackets may not be secured to the seat frame in the front-row center seating position.
- tires 2020
The vehicles may have been manufactured with Continental tires that were overcured.
- transmission & drivetrain 2020
One of the driveshaft joints may not have been properly welded, causing the driveshaft to separate while the vehicle is moving.
- airbags 2020
The diffuser component of the Roof-Rail Air Bag (RRAB) inflator may not have been properly crimped to the inflator and could separate from the inflator during air bag deployment.
- body structure 2020
Some of the vehicles in 20V-324 were not part of Recall 20V-142 but received defect parts during another service (typically during collision repair).
- latches/locks/linkages 2020
The hood-latch striker wires may not have been heat-treated properly, possibly causing them to fracture.
- brakes 2020
The bolts used to attach the front and/or rear brake calipers may have not been heat treated and may break under load.
- electrical 2019
The battery positive (B+) cable rings may have been manufactured with excessive glue, potentially causing an intermittent electrical connection between the B+ cable and alternator.
- fuel system, gasoline 2019
The fuel pump may be missing a pressure regulator, allowing for over-pressurization of the fuel system.
- seat belts 2019
When the front seat belt pretensioners deploy, hot gas may vent through an opening in the pretensioner bracket, possibly igniting the carpet.
Recall repairs are free at any dealer. A recall only matters if it's still open on that exact car, so check its VIN.
Problems GMC told dealers about
GMC sent dealers 1984 repair notes for this car. The ones about its biggest problems:
- This informational bulletin provides information on Internal Engine Noise or Damage After Oil…
- The informational bulletin explains the normal noises that are emitted from the engine once…
- Tick noise from the engine cold, initial start
Ask a seller or mechanic if these were done. Some are free under warranty or a special program.
Government investigations
- OpenLoss of motive power due to engine failure2025
- ClosedLoss of motive power due to engine failure2025
- ClosedAir bag malfunction2021–2023
NHTSA looks into a problem when enough owners report it. Many end in a recall.
Safety
Crash test details
| Version | Overall | Front | Side | Rollover |
|---|---|---|---|---|
| GMC Sierra 1500 PU/CC 4WD | ★★★★☆ | ★★★★☆ | ★★★★★ | ★★★★☆ |
| GMC Sierra 1500 PU/EC 4WD | ★★★★★ | ★★★★☆ | ★★★★★ | ★★★★☆ |
| GMC Sierra 1500 PU/RC 4WD | ★★★★★ | ★★★★☆ | ★★★★★ | ★★★★☆ |
| GMC Sierra 1500 PU/CC 2WD | ★★★★☆ | ★★★★☆ | ★★★★★ | ★★★★☆ |
| GMC Sierra 1500 PU/EC 2WD | ★★★★★ | ★★★★☆ | ★★★★★ | ★★★★☆ |
| GMC Sierra 1500 PU/RC 2WD | ★★★★★ | ★★★★☆ | ★★★★★ | ★★★★☆ |
Fuel cost and engines
About $3400–4700 a year in fuel (EPA estimate). Engines: 3.0L 6-cyl, 4.3L 6-cyl, 5.3L 8-cyl, 6.2L 8-cyl.
In owners' words
Rear tires locking up out of no where almost made me jack knife.
2020 GMC Sierra owner · NHTSA complaint 11501953
More owner reports
Bought 9-4-2020. On 9-4-2021 went start vehicle and no electrical power, battery dead. Will not hold charge to start. Brand new purchased at Morgan GMC in Shreveport Louisiana
NHTSA complaint 11431842
Brakes squeak. Started about 3000 miles. I have complained to dealer several times.
NHTSA complaint 11406920
Quick answers
Is the 2020 GMC Sierra reliable?
Yes, better than average by government complaints. It drew 1.3× fewer complaints than average filed with NHTSA in its first 3 years, per car sold (Lemon Index 75; 100 is average, lower is better). The best GMC Sierra year by this measure is 2010.
What are the most common 2020 GMC Sierra problems?
In owner complaints to the government, the parts named most are electrical (27%), brakes (24%) and engine (21%). That is the share of complaints, not the share of cars that break.
How many recalls does the 2020 GMC Sierra have?
16 safety recalls (latest: transmission & drivetrain). Recall repairs are free at any dealer; check a specific car's VIN at nhtsa.gov/recalls.
What gas mileage does the 2020 GMC Sierra get?
16 to 26 mpg combined, depending on the engine (EPA estimate).
Is the 2020 GMC Sierra safe?
NHTSA gave it 5 out of 5 stars overall in its best tested version. Ratings differ by body style, and the full table is on the advanced page.
At what mileage do 2020 GMC Sierra problems start?
Half of the owners who gave a mileage reported the problem between 4,400 and 87,000 miles. The middle report was at 31,400 miles, from 172 complaints.
Does the 2020 GMC Sierra have transmission problems?
Transmission and drivetrain issues make up 10% of its owner complaints.
How much does the 2020 GMC Sierra cost in fuel a year?
About $3400 to $4700 a year, by the EPA's current estimate.
What engines does the 2020 GMC Sierra have?
3.0L 6-cyl, 4.3L 6-cyl, 5.3L 8-cyl, 6.2L 8-cyl.
What GMC Sierra year is better than the 2020?
By owner complaints per car sold, the best recent years are 2010, 2012 and 2013.
Lemon Index = safety complaints filed with the U.S. government (NHTSA) in a car's first 3 years, per car sold, against the average car of the same model year. 100 is average; lower is better. A complaint is an owner's report, not a confirmed defect. How it works