Complaint volume
437 consumer-submitted complaints are matched to this model year. Treat the count as a research signal, then read the actual summaries for repeated symptoms.
Complaint records
2020 GMC Sierra Complaints
437 consumer-submitted complaints on record for the 2020 GMC Sierra, grouped by component category.
437 Total complaints
11 Crash reports
5 Fire reports
6 Injury reports
Complaint data reflects consumer-submitted reports. A complaint is not proof
of a defect, recall, or manufacturer fault. Enriched severity fields come
from official bulk records when the complaint can be matched by ODI number.
Buyer interpretation
How to use these complaints before buying
Complaint records are most useful when they turn into inspection points, seller questions, and comparison checks against nearby model years.
Pattern to inspect
The most common categories are engine, power train, electrical system. Use those categories as a test-drive checklist instead of judging the vehicle from the total count alone.
Severity flags
Enriched records include 11 crash reports, 5 fire reports, 6 injury reports, and 0 fatality reports. These fields come from complaint records and should be read in context.
Mileage clue
Mileage is available on 121 complaints, with an average reported failure mileage of 45,188 miles. Compare that with the mileage on the listing.
Questions to ask the seller
- Have you had any problems related to engine, power train, electrical system?
- Can I see recent maintenance and repair records?
- Has the vehicle ever been towed, involved in a crash, or repaired for the same issue twice?
- Can we also check the recall record for this 2020 GMC Sierra?
Used-car checklist
Use these complaints before the test drive.
Build a buyer checklist to turn these issues into questions and inspection points.
2020 GMC Sierra
Build buyer checklist Compare with other years Sends year, make, and model to pre-fill your checklist.
How severe are the 2020 GMC Sierra complaints?
11 Crash
5 Fire
6 Injury
0 Fatality
29 Towed
4 Medical attention
What are the most common 2020 GMC Sierra complaint categories?
ENGINE 130
POWER TRAIN 38
ELECTRICAL SYSTEM 22
POWER TRAIN,ENGINE 17
SERVICE BRAKES 16
STEERING 14
UNKNOWN OR OTHER 14
ENGINE AND ENGINE COOLING 10
SUSPENSION 9
ELECTRICAL SYSTEM,ENGINE 8
437 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| Apr 2024 | AIR BAGS | The contact owns a 2020 GMC Sierra. The contact proceeded through the intersection when a vehicle crashed into the contact's driver's side door and wheel at unknown speeds. The contact stated that the other vehicle crashed into two vehicles, then crashed into the contact's vehicle and stopped. The contact stated that the police report stated that the vehicle that crashed into the contact was constantly moving at the posted limit of 50 MPH. The air bags did not deploy. The contact was treated for a left shoulder sprain and swollen right hand, however, it was unknown if other passengers sustained injuries. A police report was filed. The vehicle was towed to a body shop but the vehicle was not repaired. The failure mileage was approximately 34,800. | Crash: Yes Fire: No Injuries: 1 Towed Medical attention | 34,800 |
| Apr 2024 | STRUCTURE,UNKNOWN OR OTHER | Rear window leak causing whole inside back to get soaked. Have paid hundreds of dollars to have sealed didn’t work. New window didn’t work it still leaks. It’s going to cause interior to mold and body to rust. Dealership and glass business both say it’s body issue and they have seen many GMC and Chevrolets with this issue. Google show 1000s with same problem. | Crash: No Fire: No | Unknown |
| Apr 2024 | STRUCTURE | GM refuses to fix a known design flaw in the back sliding glass frame on 2020_24 gmc sierra trucks. This issue will generate toxic mold as large quantities of water enter the cabin and can be extremely harmful for certain individuals allergic to mold. GM knows about this issue and tried to secretly advise techs via TSB 18-na-383 to apply sealant on the frame and if customer returns to replace frame. However they do not want to do this outside the 3 year warranty. The back glass on a truck is not a serviceable item. | Crash: No Fire: No | Unknown |
| Mar 2024 | FUEL/PROPULSION SYSTEM | 13540028 Fuel Pump Power Control Module Part failed leaving me stranded and had to get a tow. When the failure occurred, vehicle would not crank and there was no forewarning. It worked and then it didn't. The part is on notional backorder and there seems to be a lot of vehicles out there with the same issue and that just with the mechanics\service departments I've contacted that have had the part on backorder for months. So the fail rate seems high and I'm sure others got stuck in a lot worse situation than me. Then GMC continues to produce vehicles with a newer similar part while not producing the same part for like new vehicles. Which will probably only compound the backorder issue when the newer vehicles eventually have the same issue. | Crash: No Fire: No | Unknown |
| Mar 2024 | ENGINE AND ENGINE COOLING | See attached document for complaint | Crash: No Fire: No | Unknown |
| Mar 2024 | ENGINE | Vehicle has excessive oil consumption. Within 5000k oil change interval, no oil on dip stick around 3000k miles. | Crash: No Fire: No | Unknown |
| Mar 2024 | ELECTRICAL SYSTEM,VEHICLE SPEED CONTROL,VISIBILITY/WIPER | Back window frame crack led to water intrusion which flooded electric module controlling speedometer and adaptive settings. Extremely unsafe driving with faulty electrical components unknown to me. Insurance and Dealership told me this is a common GMC occurrence. Cost is near $10,000 to make truck drivable. | Crash: No Fire: No | Unknown |
| Feb 2024 | FUEL/PROPULSION SYSTEM | Fuel Pump Drive Control Module (Part No. 13540028). This item is a recall on several other vehicles, but not identified on my year/model. On 4 separate occasions over a 3-4 week period, the engine starting running very rough lost power and stalled while traveling down the road (highways, interstate, and a side street). I was finally able to pull a fault code and research the history of this code and this part on several other GMC/Chevy modeled vehicles. The dealer advised I was lucky to find the part because most of them are on backorder due to the recall on other vehicles. The one I got was for a recall, but the customer hadn't returned in time so they sold it to me. I had a repair garage replace the component on Jan 13, 2024, and haven't had any repeat issues. The check engine light did come on each time with a P129F code. It would reset after the vehicle stalled and was powered off for 10-15 minutes and the symptoms would go away. Each time left me lucky to get my vehicle over several lanes and off the side of the road. The date below was the last time it happened. The first time it happened was on Dec 6th and the vehicle started back up in just a minute or two. I still have the old part if it needs to be sent and evaluated to compare with other recalls on the item in other vehicles. | Crash: No Fire: No | Unknown |
| Feb 2024 | STRUCTURE | Rear Sliding Glass window frame has cracked and allows water to enter the cab of the vehicle. Yes this is available for inspection. The water entering the cab of the vehicle can create mold from moisture build up if left untreated. I was able to have the dealer service center confirm the issue noted in [XXX] but they were unable to repair it as it is outside of warranty. I was able to have an independent 3rd party glass company confirm that it was indeed a manufacturers defect with a cracked housing and not an issue with sealant around the glass itself. No warning lamps or other indications other than water in the back seat of the vehicle. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |
| Feb 2024 | ENGINE | 1. Valve Lifter Failure 2. While entering the [XXX] freeway and trying to merge into traffic the engine lost power and I had to swerve and brake to avoid an adjacent vehicle, and freeway traffic had to avoid my slowing down to pull over. 3.Yes, Van GMC in Scottsdale, confirmed lifter failure. 4. Yes, GMC Dealership 5. Absolutely no warning given INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |
| Feb 2024 | STRUCTURE,UNKNOWN OR OTHER | Rear Window Leaks due to failed sealing at the factory. If not fixed will ruin interior components and possibly rust. Yes No No | Crash: No Fire: No | Unknown |
| Feb 2024 | VISIBILITY | The contact owns a 2020 GMC Sierra 1500. The contact stated while detailing the rear interior of the vehicle, the contact discovered water surrounding the rear windshield casing and the water was leaking into the rear seating. Additionally, the rear carpet was soiled with water. The contact used towels while attempting to soak up the water. The vehicle was taken to the dealer where it was diagnosed that the failure was due to the failed rear windshield glass fasteners. The contact was informed that the failure had damaged the rear carpet, padding, and the rear seat. In addition, the contact was informed that the carpet and padding needed to be replaced due to mold build up. The contact was informed that the vehicle was out of warranty coverage. The vehicle was not repaired. The manufacturer was made aware of the failure but provided no assistance. The failure mileage was approximately 31,000. | Crash: No Fire: No | 31,000 |
| Feb 2024 | SERVICE BRAKES | Lost break, second time this month, showing break failed 40 mph max speed, abs light on, break light on, and 2 more light on the car with antislipiring or something like that, the another one no idea what it is | Crash: No Fire: No | Unknown |
| Feb 2024 | STRUCTURE | The back window leaks, I brought it in they told me it wasn't warranty so I paid to have it fixed. Still leaks. | Crash: No Fire: No | Unknown |
| Jan 2024 | POWER TRAIN,BACK OVER PREVENTION,FORWARD COLLISION AVOIDANCE | Lifters Failed in November 2023 and had repaired major engine damage including 4 cylinders, cam shaft, lifters, gaskets etc. After major repair work done. Truck is now doing same exact thing in January 2024. The dealership is stating they will not look at the vehicle unless i buy a new battery. I asked them to try a used battery to see if that makes a difference. And then if it is the battery i will replace. I was hung up on after the technician doug Pedersen stated ill have a supervisor call you back. | Crash: No Fire: No | Unknown |
| Jan 2024 | AIR BAGS | Driving on state highway at posted speed. A deer ran into the right front and side of vehicle. Side airbags deployed. When the right side airbag deployed, it burned a hole in my passengers winter coat that completely went through the right sleeve forearm and scorched the sweatshirt that she was wearing under the coat. Smoke was visibly apparent in the cab of the vehicle. We thought the truck was on fire , then finally determined it was the sleeve of here coat. | Crash: Yes Fire: Yes Towed | Unknown |
| Jan 2024 | STEERING | While driving, the power steering (electronic) failed. Driver Info Center gave no waring until the system failed. After failure the DEC gave a warning to "Service Poser steering". | Crash: No Fire: No | Unknown |
| Dec 2023 | UNKNOWN OR OTHER,VISIBILITY/WIPER | The rear window was leaking a substantial amount of water soaking the back seat. Had the service bulletin done, which did not work. Then under further inspection found cracks in the rear power window track. Dealer told me GM would not cover replacement because it was out of the 3 year warranty. Then was told it would cost me 1200 dollars to replace. GM should cover this because it will lead to black mold. | Crash: No Fire: No | Unknown |
| Nov 2023 | ENGINE | timing chain failure, timing chain components are available for inspection. Costly premature repair/failure. Could leave occupants stranded in unsafe environment which could lead to death. The vehicle has been diagnosed by the dealership and OEM manufacturer has been notified. There was a warning lamp. | Crash: No Fire: No | Unknown |
| Nov 2023 | SERVICE BRAKES,FORWARD COLLISION AVOIDANCE | ABS LIGHT LIMITED TO 43 MPH ESC system Steering assist reduced Service Trailer Brake System Engine light on | Crash: No Fire: No | Unknown |
| Sep 2023 | VISIBILITY/WIPER | The rear window on this vehicle is leaking water and has been for some time. It has become quite bad and is causing an odor and discoloration in the carpet. I could not find the cause of the problem until recently with the plastic cracking more. The vehicle has 41,000 miles and the dealer stated that is out of warranty and all repairs would be a cost to me. I researched this and have found it is a common fault this this vehicle. | Crash: No Fire: No | Unknown |
| Sep 2023 | STEERING,SUSPENSION,POWER TRAIN | The right side started clicking out of no where when I turn the steering wheel | Crash: No Fire: No | Unknown |
| Sep 2023 | ENGINE | I have a 202 GMC Sierra 1500 with a 3.0 Duramax with 95,000 miles. I have hade 2 glow plugs replaced under warranty and took in for a third glow plug. They stated that the there was a software update that could fix it, but I would have to pay for it. The vehicle has a 100,000 mile warranty and the software update is to fix a powertrain item that is covered under the 100,000 mile warranty. This is also an issue with bad software that disables the remote start. Not sure why I have to pay for this software upgrade to to a GM issue from day 1. | Crash: No Fire: No | Unknown |
| Aug 2023 | SERVICE BRAKES | The contact owns a 2020 GMC Sierra 1500. The contact stated while driving 60 MPH, the service brake, check engine, and ABS warning lights were illuminated. The contact took the vehicle to an independent mechanic to be diagnosed and it was determined that the passenger’s side rear caliper needed to be replaced. The vehicle was not repaired. The vehicle was taken to the local dealer to be diagnosed, and the contact was informed that the rear passenger’s side caliper needed to be replaced. The vehicle was not repaired due to the parts not being available. Upon investigation, the contact associated the failure with NHTSA Campaign Number: 20V116000 (Service Brakes, Hydraulic) however, the VIN was not included. The manufacturer had been informed of the failure. The failure mileage was approximately 69,000. | Crash: No Fire: No | 69,000 |
| Aug 2023 | FUEL/PROPULSION SYSTEM | Reference your GM/Chevy recall NHTSA [XXX] , I have a 2020 GMC truck with a failed Fuel Pump Control Module, same part/same part number used in the SUVs. Are you going to recall the trucks also. Lucky for me, mine failed as I pulled into my drive way. Had to have my truck towed to the dealership, 2 days later informed my FPCM was bad, and of course there are no replacement part available. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |