Complaint volume
425 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
425 consumer-submitted complaints on record for the 2020 GMC Sierra, grouped by component category.
425 Total complaints
11 Crash reports
4 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, 4 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 118 complaints, with an average reported failure mileage of 44,233 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
4 Fire
6 Injury
0 Fatality
28 Towed
4 Medical attention
What are the most common 2020 GMC Sierra complaint categories?
ENGINE 125
POWER TRAIN 36
ELECTRICAL SYSTEM 21
POWER TRAIN,ENGINE 17
SERVICE BRAKES 16
STEERING 14
UNKNOWN OR OTHER 14
ENGINE AND ENGINE COOLING 9
SUSPENSION 9
ELECTRICAL SYSTEM,ENGINE 8
425 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| Feb 2025 | UNKNOWN OR OTHER | 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 | Crash: No Fire: No | Unknown |
| Jan 2025 | ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated while driving and decelerating from 65 MPH to 15-20 MPH to make a turn, the engine made an abnormal knocking sound. The contact was able to drive to the residence. The dealer was notified of the failure. The vehicle was towed to Pechous Repair to be diagnosed. The contact was informed that the engine was blown and needed to be replaced. The vehicle was repaired. The contact later became aware of NHTSA Action Number: PE25001 (Engine, Engine and Engine Cooling); which the contact related to the failure. The manufacturer was not notified of the failure. The failure mileage was approximately 64,298. | Crash: No Fire: No Towed | 64,298 |
| Jan 2025 | UNKNOWN OR OTHER | Shift to park error message to turn vehicle off when already in park. | Crash: No Fire: No | Unknown |
| Jan 2025 | FUEL/PROPULSION SYSTEM | 2020 GMC Sierra Denali – VIN [XXX] On [XXX] while driving the 2020 GMC Sierra to work I noticed a strong gasoline smell inside the cabin. I immediately returned home and parked the truck in the street. Inspecting the driveway where the truck was parked over night, I notice large gasoline spot. The following day I had the truck towed to Boyds Tire & Service center to have the truck inspected. On January 20 Boyds called me and shared the truck had experienced a failure of the High-Pressure Fuel Pump which has been recognized by GM as a recall under N192283991. I called a local GMC dealership about this failure and they stated it would cost $300 to review and would not perform any work under a recall. Also, the dealership stated they could not service the truck for another two weeks, which I cannot be without the truck that long. So, I had Boyds perform the repair the same day. Unfortunately, GM has not listed my truck on this recall. This is the reason for my submittal and request for a full refund of the repair service due to the failed part. This being a very High Risk of Fire and injury and death, I decide to have the repair completed immediately. I have since contacted GM about this incident they will not consider my request for recognizing and reimbursement for service repair. GMC, Case number [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |
| Jan 2025 | STEERING | On 01/07/2025 I got in my truck to take it to GMC for an oil change and 75,000 mile service. When I began to drive I noticed I could barely turn the truck at all. The power steering was not working. Then a warning popped up to have the power steering serviced. The GMC dealership is an hour from my house. The entire drive the power steering didn't work. I explained what was going on to the GMC dealership and when they went to look at the truck the power steering was working again. When I left the dealership the power steering was working. I stopped at a friends house for about an hour and when I went to leave the power steering was not working again. I ended up having to drive an hour again with no power steering and made an appointment with GMC to get the power steering looked at. Currently they haven't commented on the Power Steering function but rather that there is a gear needing to be replaced in the steering column. Upon looking online it shows "Several model years of GMC Sierra trucks have been subject to a recall for intermittent power steering issues related to electrical glitches within the EPS system." However, my truck seems to not be on this list of affected vehicles but there is no other explanation of why this is happening with my truck and GMC has not commented on why it is happening but it is extremely dangerous. | Crash: No Fire: No | Unknown |
| Jan 2025 | ENGINE,FUEL/PROPULSION SYSTEM | On January 8th I was driving when my 2020 GMC Sierra 1500 Denali started to misfire as well as several warning lights blinking. I happen to be a couple miles from the dealership I purchased it at so I drove it straight there. A few days later I was notified it was the lifters that went bad and it would cost $5400 plus tax. This is disturbing since I have only had my truck for a little over 4 years with 68,000 miles on it. After researching the problem it appears that its a common issue and I notices a class action lawsuit for this reason. Since it's not recalled currently I'm stuck covering the invoice. Before the problem happened my truck was driving normal and no warning lights came on. This needs to be investigated so the consumer isn't stuck paying for something that is an obvious GM issue . | Crash: No Fire: No | Unknown |
| Jan 2025 | POWER TRAIN | See attached document for complaint. | Crash: No Fire: No | Unknown |
| Jan 2025 | POWER TRAIN | The contact owns a 2020 GMC Sierra 1500. The contact stated that while accelerating from a stop light, the rear wheels seized. There were no warning lights illuminated. The vehicle was diagnosed by a mobile mechanic with transmission failure. The vehicle was towed to the residence. The dealer was informed of the failure. The contact was informed by the dealer that the repair was not covered under warranty due to the mileage. The vehicle had not been taken to the dealer. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was 82,000. The VIN was not available. | Crash: No Fire: No | 82,000 |
| Jan 2025 | POWER TRAIN,ENGINE | Motor seized at 52,000 miles.... replaced motor... at 72K miles, lifters and rods had to be replaced on the 2nd motor. Transmission also failure at 72K, being replaced. | Crash: No Fire: No | Unknown |
| Jan 2025 | ELECTRICAL SYSTEM,FORWARD COLLISION AVOIDANCE | Driving down highway at 60 mph and truck shut off. had to try to get it over to the shoulder to off the travel lane. Dealer found wire harness chaffed at front left shock tower ECM bracket. Several wires damaged, repaired and cleared codes. This could have been much worse had I been in heavy traffic and needed to cross additional lanes of traffic to park in a safe area. I had no power steering and limited space to park the truck. I called to police to have a car dispatched to park behind me so the truck could be loaded on a tow vehicle to bring it to the dealer. This could have been worse had my wife been driving. | Crash: No Fire: No | Unknown |
| Jan 2025 | POWER TRAIN | The truck was dropped off on November 11th of last year due to a valve body failure, and I’ve been informed that repairs cannot be completed because the necessary parts are unavailable. I purchased the truck in late August of last year and am now stuck making payments on a vehicle I can’t even drive. When I approached the GMC dealer about trading it in or having them buy it back, they said trading it in was an option but couldn’t offer anywhere near what I paid. To make matters worse, they have no timeline for the repairs, and buying it back isn’t an option. | Crash: No Fire: No | Unknown |
| Jan 2025 | LANE DEPARTURE | ADDITIONAL INFORMATION RE ODI 116346689: Tried to report to GM using 800-462-8782 provided by you. Agent would not accept ANY information that I tried to provide, including year/make /model and would not confirm or deny that the issue was known by them. Agent said that the dealer would report their inability to fix the issue directly to GM, and that I could not. I have no way of knowing if the dealer made this report to GM. Calling this number was an infuriating, complete waste of time. | Crash: No Fire: No | Unknown |
| Jan 2025 | ENGINE,FUEL/PROPULSION SYSTEM | I had Engine Failure in June 2024 with roughly 50,000 miles. I was getting on I75 North in Auburn Hills, MI, when I heard a loud pop. The vehicle began shaking violently with a loss of engine power warning displayed, loss of oil pressure displayed followed by 2 successive limp mode warning. The vehicle would not drive over 25 MPH. Luckily the next exit was only a mile down the road. I was able to drive on the shoulder of the Interstate to get off of the highway. When I parked the vehicle shortly after, I viewed oil spewed all over the engine bay and under the truck. I then waited 4 hours in 95+ heat for a tow truck. The engine was replaced by the dealer with no root cause identified or communicated to me. There were no warning prior to this failure. The vehicle has had over 13 warranty related issues including the DEF heater melting, CAC pump failure, Numerous Exhaust Leaks, NOX and EGR sensors failing, brake control module faults etc. | Crash: No Fire: No | Unknown |
| Jan 2025 | STEERING,ELECTRICAL SYSTEM,ENGINE | On [XXX], I was driving my truck on [XXX] through Phoenix, AZ. It was 5 days after I had purchased the vehicle and only had 250 miles on the odometer. I was in the left lane was traveling at approximately 75mph. Within the span of about 20 seconds, several lights on the dash annunciated and several messages including a message about a brake failure and steering assist failure and then the engine suddenly turned off. The steering seemed heavy and the brakes seemed less responsive. I was able to coast to a stop on the side of the road thanks to the help of a couple truckers who blocked traffic across multiple lanes. The truck was towed to the dealer and they told me the entire engine needed to be replaced. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |
| Jan 2025 | LANE DEPARTURE | The contact owns a 2020 GMC Sierra. The contact stated that while driving at speeds over 38 MPH, and the Lane Departure Warning System was activated the seat indicator did not vibrate or sound an alert as intended. The vehicle was taken to the dealer where the software was reset but the failure persisted. The manufacturer was not notified of the failure. The failure mileage was 47,000. | Crash: No Fire: No | 47,000 |
| Dec 2024 | FUEL/PROPULSION SYSTEM | GDI fuel pump went bad needed replacement. | Crash: No Fire: No | Unknown |
| Dec 2024 | POWER TRAIN | The contact owns a 2020 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 24V797000 (Power Train); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The contact stated that there was a loud clanking sound underneath the vehicle while starting the vehicle. There were no warning lights illuminated. The vehicle had been taken to the dealer and was diagnosed with transmission failure. The contact stated that the transmission had been repaired twice however, the failure persisted. The vehicle was taken to the dealer again and the transmission was replaced. The dealer was contacted about the recall and confirmed that the VIN was included in the recall however, the part to do the recall repair was not yet available. The manufacturer was not made aware of the issue. The failure mileage was 50,000. Parts distribution disconnect. | Crash: No Fire: No | 50,000 |
| Dec 2024 | BACK OVER PREVENTION | The contact owns a 2020 GMC Sierra 1500. The contact stated while reversing the vehicle, the rearview camera image failed to display as needed, and the radio was inoperable. The vehicle was taken to the dealer, but the cause of the failure could not be determined. The vehicle was not repaired. The manufacturer was made aware of the failure and a case was opened. The failure mileage was approximately 3,500. | Crash: No Fire: No | 3,500 |
| Dec 2024 | SERVICE BRAKES | My pickup was specifically purchased to pull a duel axle trailer ( brakes required by Fl. Law). The trailer weights more than the pick up. They stopped working with the electric /hydrolic Trailer brake system. I have had the Sierra in three times for Warren Ty repair. They never fixed the system. I have thoroughly test the trailer system - it works fine with another pickup. Dealer won’t return my calls. Multiple trips taking it in for this problem. Have a case filed with GM. All just placating me, now ignoring my problem. I am stuck and they are not acting in good faith. | Crash: No Fire: No | Unknown |
| Dec 2024 | POWER TRAIN,VEHICLE SPEED CONTROL,FUEL/PROPULSION SYSTEM | Shuttering while in motion at a speed of 35mph or above. My 2020 GMC SIERRA 1500 AT4 CarbonPro while driving at or above speeds of 35mph experiences a hesitation and severe Shuttering while trying to maintain any speed of 35mph or above. The hesitation causes extreme vibrations and hesitation when lifting or applying foot to the accelerator. This happens in any drive mode also with cruise control on or off as well as shifting into low and being in any gear trying to prevent it. It also does this on any road and condition. It feels like a slip in the transmission or torque converter, possibly could be the rear end or variable valve timing as well. And when taking of from a red-light or stop sign it slips as if the truck has lost traction, but it hasn't. This is very dangerous and could be the cause of a serious accident when trying to accelerate. If your traveling at hwy speeds it feels as if the brakes are being applied and the tires are going over a washboard which could cause a collision, tire wear, or driveline damage. | Crash: No Fire: No | Unknown |
| Dec 2024 | ELECTRICAL SYSTEM,STRUCTURE | Tailgate releases on its own while parked, without the use of the switch. Tailgate released on its own with my trailer attached while parked on many occasions. The result of the Tailgate releasing caused damage to the upper section of the Tailgate, the "kicker speaker system" in the Tailgate and Tailgate switch located on the upper section of the Tailgate. There also have been multiple times when attaching the trailer that the Tailgate has released and struck me in the head. The Tailgate also fills with water during rain, and carwashes. The damage caused by the Tailgate releasing is a dent on the upper section of the multi-pro Tailgate and rust and malfunction of the " kicker speaker system " as well as the occasional hickey and headache on my head. The Tailgate has filled up with water since I purchased it new in December of 2020 which I believe has been electricly shorting the Tailgate switch/button releasing the Tailgate randomly. Due to my particular 2020 GMC Sierra 1500 AT4 CarbonPro having the " kicker speaker system " in my opinion makes the Tailgate so much heavier than one without it that it made the damages such as the dent in the face above the Tailgate switch much worse than trucks without it also causing more water to enter the Tailgate causing more damage to the switch and components of the " kicker speaker system ", such as the amp and buttons for it not to mention my head on several occasions. | Crash: No Fire: No Injuries: 1 | Unknown |
| Nov 2024 | ENGINE | The contact's son owns a 2020 GMC Sierra 1500. The contact stated while driving at various speeds, the vehicle shut off without warning. The contact stated that the vehicle was restarted and resumed normal operation moments after the failure. The contact stated that the failure recently started occurring more frequently. The manufacturer was notified of the failure and the contact was provided a case number. The contact was referred to the NHTSA Hotline to report the failure. The vehicle was not repaired. The failure mileage was approximately 40,000. | Crash: No Fire: No | 40,000 |
| Nov 2024 | POWER TRAIN,ELECTRICAL SYSTEM,ENGINE | DEF Emissions warning and Engine Emissions warning lights suddenly appeared. DEF Emissions warning went on and off multiple times in the two days before bringing to a GMC service location. Informed that the DEF Tank heater failed, a known problem, but that they likely would not have a repair available for over a month and would not be covered by any warranty. The vehicle is now speed limited to unsafe speeds on highways while waiting for the repair. | Crash: No Fire: No | Unknown |
| Oct 2024 | POWER TRAIN,UNKNOWN OR OTHER | There has been a recall on the 2020 sierra 1500 for the driveshaft which causes shuddering and vibration which my vehicle is exibiting but my vin is not on the recall list | Crash: No Fire: No | Unknown |
| Oct 2024 | POWER TRAIN,ENGINE,FORWARD COLLISION AVOIDANCE | At 103,000 my 2020 AT4 5.3L V8 had a P0307 code thrown. Cylinder 7 misfire. Driving highway speeds, sudden loud pop and then the service engine light came on and automatic braking engaged, and the idle got extremely rough. Ended up being a bad lifter, bent rod, tore lobe off of the camshaft. Roughly 8,000 for the repair, new cam, new lifters, spark plugs and coil packs. Now only about 3,000 miles later, driving, sped up to pass on the interstate and another misfire, P0306 this time Cylinder 6. Same symptoms check engine light, automatic braking, rough idle. Seems to be another failed lifter and bent rod. Currently awaiting diagnostic for this second misfire issue. When speaking with the tow truck driver and the mechanic both mentioned a significant rise in cases like this. There is definitely something wrong with the design that the manufacturer needs to be help responsible for. I have less than a month ago replaced all the lifters only to have another one fail again. | Crash: No Fire: No | Unknown |