14 complaints reported

2020 GMC Sierra 1500 UNKNOWN OR OTHER

Owner-reported problems and safety issues filed with NHTSA. Review common failures, severity levels, and complaint trends over time.

Reports
14
Crashes
0
Fires
0
Injuries
0

Complaint Timeline

Chronological view of owner reports

Jan 2026

Transmission 10l80 stuck solenoid truck has hesitation delayed shifting. And will not shift after certain gears.

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Dec 2026
Dec 2025

My doors will no longer lock or unlock, using the key fob or the lock/unlock buttons in the vehicle. This is a widely known issue for GMC Trucks, once you search for it. At around 50K Miles, the door actuators just quit working. So, if I have kids in my truck, I can't unluck the doors to get them out unless I climb through the truck, and have to manually do same to lock the doors to drive with kids in the car. There isn't a key hole for the back doors, so this can't be done at all outside the car. The doors are supposed to automatically lock when the truck is put in gear. Mine won't lock even when I push the button to lock. I just had this confirmed at the dealer. I also spoke to GMC and was told that it wasn't their responsibility. This is a genuine safety issue, and happens on these trucks a LOT.

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Dec 2025
Nov 2025

Safety Recall N242454440 Momentary Rear Wheel Lock-Up was issued for 2020 to 2022 GMC Sierra 1500 but mine is not included. I drive a 2020 GMC Sierra 1500. It is experiencing harsh shifting and now there is a feeling in the rear wheels like they are trying to get stuck or hang up. Why is my truck not included?

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Nov 2025
May 2025

Engine light came on while driving / aligned to transmission temp sensor error and brake sensor GM Maintenance was able to diagnosis that the Temperature Loop Coolant Pump had failed and needed to be replaced.

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Jan 2024
May 2025

Rear window is leaking top coners from seal or plastic creating black mold inside of truck

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Dec 2024
May 2025

I purchased a 2020 GMC Denali Sierra 1500. My oil light has came on twice and I have taken it into the dealer and dealer has said that that's normal. That car loses oil. I'm retired so I do not utilize the vehicle every day I think since I've had the vehicle I've put on several thousand miles very very low mileage put on. And I'm being told that I need to check the oil basically before I take the vehicle anywhere. During the first time when I bought the vehicle in when the light came on the mechanic said in the paperwork from GMC service that my engine oil was extremely low. This last time that I did take it in, I have some type of mechanical background, so I pulled the dipstick out and it was halfway full with oil. I took a picture of that dated the picture and said I took it in before service while when I took it into the service department of course when I came home, they said that everything's fine and so on and so on and that didn't sit well with me. So I went ahead and let the car settle. Let the car cool down several hours later. I went ahead and checked the dipstick and the dipstick was full. They went ahead and put oil into my vehicle and told me that everything's fine. And I have noticed that there are lawsuits out in regards to oil consumption issues on these vehicles. When somebody spends the amount of money they spend for these vehicles we should not have to be checking the oil almost every time we drive it. I've had multiple vehicles on 50 years old and I've never had to check the Oil like it was 1914 before you go on a trip or even drive your vehicle. I am not trying to blame the Dealership only being told that everything's fine but GMC the company needs to rectify this problem because there is going to be a time that people are going to forget about the oil and burn up an engine and then you're putting them out thousands of thousands of dollars because of a mistake GMC made they're trying to cover it up as you see with the current recall in regards t

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Jan 2025
Mar 2025

Shift to park message appears when in park and engine is turned off. Transmission control had an internal circuit failure. Park not fully engaged and vehicle could roll. Problem confirmed by dealership. Prior recalls for earlier gmc models but not my year.

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Jan 2025
Jan 2025

Shift to park error message to turn vehicle off when already in park.

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Jan 2024
Jan 2025

Water entering from the rear window causing rear seats and roof hard cover to get wet and cause a wet odor (humid). 2020 GMC 1500 AT4

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Jan 2025
Sep 2022

Once vehicle is put in park, the control panel comes and reads, “shift in park and radio and head lights stays on as well”. I exit the vehicle and it continues to display the mention above. I’ve restarted the vehicle and put it back in park still the “shift in park”, stays on. I exit the vehicle and monitored the vehicle for approximately 5 minutes and finally turned off. This never happened before, I’m afraid it may stay on one of these days and run the battery down.

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Aug 2022
Apr 2022

Rear window (the one that faces straight back towards bed of truck) is leaking… Haven’t taken it in to dealership for repair because I’ve exceeded mileage so truck is no longer under warranty… Not sure how long it’s been leaking but I’ve recently noticed that water stains (runs) on the inside of this window after rains, washes, etc…

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Apr 2020
Jul 2020

AFTER VEHICLE SITS IDLE FOR A WHILE, THE VEHICLE MAKES A HIGH PITCH WHISTLING SOUND ON STARTUP THAT LAST FOR APPROXIMATELY MINUTE OF DRIVING.

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Jul 2020
May 2020

CAN NOT SEE ANYTHING BACKING UP IN THE DARK BECAUSE OF BACKUP CAMERA. THE PICTURE ON THE SCREEN IS GRAINY AND WASHED OUT SO ALL YOU SEE ARE BLOBS OF NOTHING. *TR

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Jan 2020
Jan 2020

THE BACKUP CAMERA IS ENTIRELY TOO BRIGHT AT NIGHT. IT IS NEARLY IMPOSSIBLE TO SEE THE MIRRORS DUE TO THE BRIGHTNESS

Type: Vehicle, Vehicle: 2020 GMC SIERRA 1500, Manufacturer: General Motors, LLC
Incident: Jan 2020

Trend Over Time

Complaints by year

Quick Summary

The 2020 GMC Sierra 1500 has 14 UNKNOWN OR OTHER complaints on file. Review the timeline above for detailed owner experiences.