2020 GMC Sierra Denali Problems
Owner-reported complaints filed with NHTSA, grouped by component
Data refreshed
What this page shows
Everything below is an owner-reported complaint submitted to NHTSA about the 2020 GMC Sierra Denali, grouped by the component NHTSA recorded on the report. These are not confirmed defects, and they are not recalls. NHTSA does not verify most reports before publishing them, and a category with more reports in it is not evidence that a part is defective.
Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.
Reports by component
Ranked by how many owner reports name each component category
- Engine660.0%
- Brakes220.0%
- Driver assistance110.0%
- Electrical110.0%
Percentages are of component mentions. A single complaint can name more than one component, so these do not sum to the total complaint count.
Each component in detail
What the reports in each category say, in the owners' own words
Engine
Reports naming the engine itself — including stalling, misfires, oil consumption, cooling and internal engine components.
From owner reports, verbatim
The contact owns a 2020 GMC Sierra 1500 Denali. The contact stated that while parking the vehicle, there was an abnormal grinding sound coming from the engine. There was no warning light illuminated. The local dealer was contacted about the failure; however, the vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 98,500.
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. There was no warning light illuminated. The contact made several attempts to restart the vehicle; however, the vehicle failed to restart. Due to the failure, the vehicle was towed to the dealer where a diagnostic test was performed. The contact was later informed that the engine had seized due to engine bearing failure, and the contact was provided an estimate for a new engine. Upon investigation, the contact discovered NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling) and linked the recall to the failure. The manufacturer was notified about the failure and the recall, and the contact was informed that the VIN was not included in the recall. The vehicle was not repaired and remained with the dealer. The failure mileage was approximately 190,000.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Brakes
Reports naming service brakes, the antilock braking system, brake hoses, master cylinders or the parking brake.
From owner reports, verbatim
BRAKES SQUEAK. STARTED ABOUT 3000 MILES. I HAVE COMPLAINED TO DEALER SEVERAL TIMES.
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
Too few reports in this category for a page of its own — they appear in the full complaint list.
Driver assistance
Reports naming forward-collision avoidance, lane keeping, back-over prevention, cruise control and related electronic driver-assistance systems.
From owner reports, verbatim
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 the vehicle got too close to another vehicle, the Adaptive Cruise Control feature failed to activate as designed. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was not made aware of the failure. The failure mileage was approximately 6,700. The VIN was unavailable.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Electrical
Reports naming the electrical system — wiring, battery, charging, control modules, infotainment and electrical accessories.
From owner reports, verbatim
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. The failure mileage was unknown.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.
Elsewhere on this vehicle
Data sources
- NHTSA Office of Defects Investigation — owner-reported complaints and the components recorded on them
Data on this page last refreshed .