Complaint volume
424 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
424 consumer-submitted complaints on record for the 2020 GMC Sierra, grouped by component category.
424 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
424 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| Sep 2025 | POWER TRAIN,ENGINE,FUEL/PROPULSION SYSTEM | 2020 gmc sierra 1500 elevation 5.3l engine. Lifter failure due do faulty design I’m afm/dfm systems. | Crash: No Fire: No | Unknown |
| Sep 2025 | POWER TRAIN,ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at various speeds, the vehicle jerked abnormally while depressing the accelerator pedal. A dealer was contacted. The vehicle was taken to the dealer, and the technician informed the contact that the failure might be related to the engine or transmission; however, the contact was informed that the vehicle needed to be inspected to determine the cause of the failure. The vehicle was not repaired. The contact stated that the failure had occurred several times. The manufacturer was notified of the failure and informed the contact to file a complaint with the NHTSA Hotline. The approximate failure mileage was 41,248. | Crash: No Fire: No | 41,248 |
| Sep 2025 | STEERING | The contact owns a 2020 GMC Sierra 1500. The contact stated that upon start the vehicle, the vehicle lost power steering functionality. The messages “Service Power Steering”, “Power Steering Disabled” were displayed, and ESC warning light was illuminated. The vehicle was taken to a local dealer where it was diagnosed, and the contact was informed that further diagnostic tests were needed to determine the cause of the failure. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 115,000. | Crash: No Fire: No | 115,000 |
| Sep 2025 | POWER TRAIN | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the transmission experienced rough gear shifts. Additionally, the vehicle shuddered while driving. The vehicle was taken to an independent mechanic, who was unable to diagnose the vehicle due to a lack of diagnostic equipment. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 120,000. | Crash: No Fire: No | 120,000 |
| Sep 2025 | ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving approximately 40 MPH, there was an abnormal knocking sound coming from the engine compartment. The contact stated that several unknown warning lights were illuminated, and several messages were displayed. The vehicle was driven to the side of the road to safety and turned off. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure. The failure milage was approximately 76,000. | Crash: No Fire: No | 76,000 |
| Sep 2025 | SERVICE BRAKES, HYDRAULIC,ENGINE,BACK OVER PREVENTION | The contact owns a 2020 GMC Sierra 1500. The contact stated that on several occasions while the vehicle was started, the check engine, brake system, and another unknown warning light illuminated. Additionally, the messages brake system failure, steering wheel failure, low oil, and two other unknown messages were displayed. The contact also stated that the rear-view camera remained displayed while shifted into drive, and the instrument panel failed to operate as intended. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 65,000. | Crash: No Fire: No | 65,000 |
| Sep 2025 | ENGINE | Vehicle: 2020 GMC Sierra Denali 1500 (VIN: [XXX] ) Description of the Problem: My 2020 GMC Sierra Denali has developed serious engine problems that create unsafe driving conditions. On [XXX], I documented loud knocking and clicking noises coming from the engine. The vehicle also shows warning lights and unpredictable performance. Because of these defects: •I cannot safely drive the truck without risk of engine failure while on the road. •The noises and mechanical issues raise concerns about potential loss of power, stalling, or catastrophic engine damage at highway speeds. •No independent mechanic will touch the vehicle because of the complexity and risk of the defect, leaving me stranded. General Motors has refused to take responsibility, and the BBB AUTO LINE denied my case due to mileage, but the defect itself is unrelated to mileage or normal wear. This is a manufacturer defect that creates a safety hazard for me, my family, and other drivers on the road. What I’m Requesting: I am asking NHTSA to investigate this issue with GMC Sierra models, as these engine defects make the vehicle unsafe to operate and could lead to accidents if the engine fails while driving. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6) | Crash: No Fire: No | Unknown |
| Sep 2025 | STEERING | My extended warranty expired. I got my oil changed at valvoline and then 2 days later my power steering stopped working and I’m getting multiple dash messages of other systems malfunctioning. Did gmc cause this to get me to come back to their service center. It seems very suspicious | Crash: No Fire: No | Unknown |
| Aug 2025 | ENGINE,FUEL/PROPULSION SYSTEM | My 6.3l v8 Started having a slight misfire while driving. Took vehicle to a mechanic and was advised to change the spark plugs, changed spark plugs, spark plug wires, and ignition coil packs while still experiencing sudden misfires while driving. Starting to consider the 6.2L L87 collapsing cylinder issue. | Crash: No Fire: No | Unknown |
| Aug 2025 | STEERING,ELECTRICAL SYSTEM,SERVICE BRAKES | Was driving down the freeway around 65 miles an hour attempted to pass a truck when the steering started wobbling the ABS that EMS and the breaking system came on with the check engine light almost had no control and barely avoided having an accident the only way it went back to normal was slowing down. | Crash: No Fire: No | Unknown |
| Aug 2025 | SERVICE BRAKES | My vehicle displayed numerous brake failure codes and limited my speed to 43mph. When taken into my local GMC dealer the diagnostics I was given were a bad/leaking master cylinder. This vehicle has 16,200 miles on it and was never used for towing or hauling. The brakes are hard and brake assist has clearly failed. I’ve found numerous recalls and issues with other year vehicles from GMC, yet they are denying any liability on my vehicle. They want over $3000 to replace the master cylinder even though there’s no physical leak observed via fluid loss. This is a major safety concern when a major brake component fails on such a low mileage vehicle. This truck also has a well known seal leak on the rear window that causes mold to grow inside of the vehicle cabin. Apparently no one has died yet so they have not been forced to put out a recall. Consumers should not be forced to spend thousands of dollars on major components on such low mileage vehicles. Especially when it comes to safety items like braking. I’ve researched this for hours and have found this has been a known issue on these 2020 models many people. Some even brand new after driving them off the dealership lot. Clearly there is an issue and the manufacturer refuses to address it. | Crash: No Fire: No | Unknown |
| Aug 2025 | UNKNOWN OR OTHER | 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. | Crash: No Fire: No | Unknown |
| Aug 2025 | POWER TRAIN,ENGINE | I have a 2020 sierra 1500 6.2 with 86,000 miles. I have only had this truck 6 months. This was inspected before I purchased with no engine issues. Since purchasing we have driven less than 6000 miles. While driving my vehicle the rod in the engine failed and started knocking. I am a mechanic and I am GMC master certified. Both myself and the owner of the shop I work at diagnosed the vehicle with a bad engine. We looked at the recall for the 6.2 engine and noticed that many of the 2020 vehicles with this engine have the same issue that is currently being recalled for this specific engine. I called GMC and they won’t fix the issue that the vehicle is having. They won’t perform the recall and again I have only had this vehicle for 6 months and with 86,000 miles should not be having this issue. I am GMC certified and told them that I looked into the recall and they them selves state that some of the defective engines got out into the 2020 models. | Crash: No Fire: No | Unknown |
| Aug 2025 | ENGINE,FUEL/PROPULSION SYSTEM | For approximately the last year (2024-2025) my 2020 GMC Sierra 1500 AT4 with the 6.2L engine has had noticeable ticking, knocking, and unprovoked shaking upon start up and idle. The pickup has stalled out at stop lights and intersections in the past, posing risk. In June (2025) the pickup was taken to a certified mechanic for inspection who suggested possible lifter or valve failure. The vehicle exhibits a persistent ticking sound from the engine, which I believe may be related to lifter or valve issues, similar to those reported in lawsuits against GM for 2019-2024 models and the recall for 2021-2024 models (NHTSA Recall ID: 24V-676). This ticking occurs regularly, including at approximately 54,500 miles, and raises concerns about potential engine failure or sudden loss of propulsion, which could be hazardous, especially at highway speeds. I have noticed approximately 2 quarts of engine oil usage per my last 2 oil changes (roughly every 6,000 miles). I recently had taken the pickup to a local GM dealership where they informed me that I am not longer covered under warranty and the recent recall is not applicable. I was advised to “keep and eye on it, and get a AAA membership”. I am aware of at least 10 class action lawsuits against GM for similar engine issues in vehicles like mine, suggesting a widespread defect. These issues, combined with the potential for engine failure or impaired vehicle control, warrant investigation to ensure driver safety. I have records of the ticking sound and can provide further details if needed. I am willing to cooperate with NHTSA for inspections or further documentation. | Crash: No Fire: No | Unknown |
| Aug 2025 | ENGINE,ELECTRICAL SYSTEM,EQUIPMENT | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving with cruise control mode set at 55 MPH, the vehicle independently accelerated to 98 MPH, and then the vehicle lost motive power. Additionally, the contact stated that the vehicle had failed to turn off upon pressing the Engine Start/Stop button. No warning light was illuminated. The vehicle was able to restart and was taken to a local dealer to be diagnosed, but the cause of the failure could not be determined. Additionally, the contact noticed that water was leaking inside the vehicle through the rear window on rainy days. The contact stated that the infotainment screen had failed to turn on as intended on some occasions, and the screen had displayed a rearview camera image while the vehicle was in drive(D) on other occasions. The contact stated that while driving at various speeds, the transmission made an abnormal sound, and the RPMs failed to decrease as intended, but suddenly dropped while decelerating. Additionally, the contact stated that the headlights, the fuel pump, and the main pulley were replaced at the local dealer. The vehicle was not repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 250. | Crash: No Fire: No | 250 |
| Jul 2025 | ENGINE,FORWARD COLLISION AVOIDANCE | My GMC had a terminal engine failure around 5/3/25. This disengaged the ESC, parking brake, and driver assist abilities as well as making the truck undrivable. GMC service diagnosed the truck needed an entire new engine. The repair took over 2 months to complete and now that I have the truck back, the adaptive cruise control is not working. | Crash: No Fire: No | Unknown |
| Jul 2025 | ENGINE | Check engine light came on. Cooling fan for engine running none stop. Reduce power mode from engine. Took to dealer, said it’s the coolant control valve. Dealer said the part is on back order and don’t know when they will get it in. Looked up the issues and sounds like many people are having the same problem with the 3L diesel from GMC. These people reporting the same thing and having to wait months for the part. My truck was just out of warranty by 200-300 miles | Crash: No Fire: No | Unknown |
| Jul 2025 | UNKNOWN OR OTHER,LANE DEPARTURE,BACK OVER PREVENTION | 1. Lane Keeping Assistantance: The green vehicle indicator on the dashboard will disappear and stay off while driving. When it is off, it is unsafe. 2. Parking Collision Warning: The front and back sensors will disappear and become nonfunctional while driving and parking. Sometimes they activate for no reason as well. 3. Both exterior mirrors: After starting the engine to drive off , both exterior mirrors will lower automatically from my setting. After the truck is started and driven off, they must be rest again. | Crash: No Fire: No | Unknown |
| Jul 2025 | STRUCTURE,UNKNOWN OR OTHER | My multipro tailgate on my 2020 GMC Sierra 1500 unlatched while a trailer was attached and backing up said trailer. The trailer jack post proceeded to buckle the upper part of the tailgate assembly causing extensive damage resulting in over a three thousand dollar repair bill. If the tailgate had released while a child was in close proximity, serious injury may occur. The tailgate has inadvertently released twice in the five plus years I have owned it, the first time as I was traveling down a highway at over 60 mph. This could have endangered a vehicle to my rear if cargo had been released on to the road. I have reached out to a local dealership for repairs and assessment, no real way of troubleshooting something that has happened twice in five plus years. The scan did not show any codes. the info center does notify you if it is released but not before it takes place and after the fact may be too late in some circumstances as it was during the second occurrence. There has been a recall on 2500 and 3500 models with the exact same tailgate but not the 1500 models. 820K vehicles affected but not on the 1500's. | Crash: No Fire: No | Unknown |
| Jul 2025 | ENGINE | On June 19th, 2025, I was driving to work when my truck began to lose power, and the check engine light came on. The error on the display is Loss of Engine Power. I took it immediately to Oreilly's so they could run the free engine light check. When they got the report, the employee was amazed that there were over 45 problem codes showing up. As I drive the vehicle there is a pull back from the engine before it starts to pick up speed. On braking as well there is a little kickback before it comes to stop. It takes more foot pressure to pick up speed. The Truck using up more fuel because of this issue. I took the truck to a local certified mechanic, and he ran the diagnostics as well and it came up with the over 45 problem codes as well. His recommendation unfortunately was to take into the dealership so they could check it and see if they have a solution for this engine malfunction and error codes. | Crash: No Fire: No | Unknown |
| Jul 2025 | ENGINE | Engine overheating at 50,000 miles. Temp would intermittently jump up to 230plus degrees while driving. Radiator replaced per dealership diagnosis. Issue still happening. | Crash: No Fire: No | Unknown |
| Jun 2025 | ELECTRICAL SYSTEM,ENGINE | Woke up one morning and the entire back seat, entire truck flooring was soaking wet. Got it to Gerber collision in El Reno, Oklahoma. They said that the back window had a crack in it. My insurance said it is a mechanical issue on the sliding back glass and they do not cover such issue. Also want to turn in that the transmission in this truck had to be replaced two week prior to this incident. The truck only had 118,000 miles on it. Safe to say that this 10 point GMC diesel truck is a nightmare and the entire truck is a hazard. They need to take these truck off the market. | Crash: No Fire: No | Unknown |
| Jun 2025 | POWER TRAIN | I had the rear wheel recall done not long ago and 2 days ago my transmission shuddered. | Crash: No Fire: No | Unknown |
| Jun 2025 | SERVICE BRAKES | I will start by saying that I have had this issue since I had the truck (2020), less than 10k miles. I mentioned to the dealer multiple times. I was told that they can't figure it out since it has to be doing it while it is at the dealership to figure it out. I am finally fed up with that answer. The issue is with trailering. It will randomly lose trailer brakes while driving down the road. Sometimes the brakes will come back right away, sometimes they will not. Other times other lights that should be working will randomly stop working as well such as turn signals. This has happened multiple times and I only tow a few times a year when I pull my travel trailer. I have a video of it doing it as I am driving down the road. For the additional details with approximate date that this incident occurred, I will put the last date that this was found. | Crash: No Fire: No | Unknown |
| Jun 2025 | ELECTRICAL SYSTEM | Power Steering works sometimes and then stops Trailer Break system issues | Crash: No Fire: No | Unknown |