Complaint volume
436 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
436 consumer-submitted complaints on record for the 2020 GMC Sierra, grouped by component category.
436 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
436 total complaints on record
Latest complaints
| Date | Component | Summary | Severity | Mileage |
|---|---|---|---|---|
| Nov 2025 | SERVICE BRAKES, HYDRAULIC,ENGINE AND ENGINE COOLING | The contact owns a 2020 GMC Sierra 1500. The contact stated while driving 45-50 MPH, the check engine warning light and the brake warning light illuminated. Additionally, the contact heard an abnormal sound coming from the engine, and the vehicle decelerated. The vehicle was taken to the dealer, where it was diagnosed and determined that all the engine lifters and the camshaft needed to be replaced. The vehicle was repaired. The contact related the failure to NHTSA Action Number: EA25007 (Engine and Engine Cooling). The manufacturer was notified of the failure and informed the contact that the VIN was not under recall. The manufacturer offered to partially cover the cost of the repair. The failure mileage was 107,787. | Crash: No Fire: No | 107,787 |
| Nov 2025 | ENGINE | Engine fan has been constantly running, with engine temp reading around 230 consistently. After driving 5 miles on the interstate it shot up to 260 and said “engine temp overheating, idle engine”. | Crash: No Fire: No | Unknown |
| Nov 2025 | ENGINE | I am Having direct issues with the engine when the vehicle is started and continues while idling or driving at any rate of speed.There's a continuous "Knocking" noise that has concerned me for a while now. My vehicle (2020 GMC Sierra 6.2 liter gas engine) with almost 100,000 miles has been doing this for a while now (at approximately 50,000 miles) and (was documented at the dealership when I made a complaint which included what I considered the vehicle to be using/losing more "oil consumption" than the normal 3-4 quarts between oil change) dating back to 2022 0r 2023 when I was told by the dealership that the amount of oil being used/ lost still fit within the manufacturers specifications. | Crash: No Fire: No | Unknown |
| Nov 2025 | POWER TRAIN | My truck had engine failure while at the dealership getting new tires installed on 11/12/2025. When they started my truck they detected major knocking in my engine the 1st thing in the morning. It unsafe to drive they're telling me my engine needs to be replaced. My engine has 58,000 miles on it. There was no issues with my truck when I drop it off. | Crash: No Fire: No | Unknown |
| Nov 2025 | ENGINE | The engine failed and started burning oil at a rate of 3 quarts every two weeks. The vehicle is currently at the GMC dealership having the engine rebuilt at a cost of over 15,000. The vehicle has approx. 116,000 miles at time of failure, so it is outside of the manufacturers warranty. The GMC dealership (Fred Anderson Greer) has photos. The engine is a 6.2L but not currently under recall as it is a 2020, the recall includes 2021 - 2024 models. | Crash: No Fire: No | Unknown |
| Nov 2025 | UNKNOWN OR OTHER | 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? | Crash: No Fire: No | Unknown |
| Nov 2025 | ENGINE | My 2020 GMC Sierra 1500 Denali with the 6.2L L87 V8 just began experiencing a new rough idle with intermittent RPM dips. There are no engine codes or warning lights. Idle drops are noticeable, suddenly began this week. I am concerned due to ongoing NHTSA Engineering Analysis EA25-007 involving this engine. Some owners reported engine failure with little warning. The truck has right over 68,000 miles on it and has had every oil changed performed at a GM dealer. I have had to top off the oil between cycles and always used the recommended oil, being the Dexos Gen 3 due to the truck burning a small amount of oil. More detail on a possible cause. I believe it would be worth investigating the DFM technology. I will be performing a fuel cleaner and possibly a lifter cleaner and/or additive. I would like to tune the truck and turn off the DFM since this is what I have read causes the truck to burn oil and damage the lifters. However, I will wait until this Analysis is completed before deciding to change the truck's stock tunes. | Crash: No Fire: No | Unknown |
| Nov 2025 | ENGINE | My engine is currently being torn down at the dealership.I heard a ticking noise coming from my engine so I took to the dealership I bought it from and when they did their diagnostics and inspection they said it was a connecting rod bearing failure. | Crash: No Fire: No | Unknown |
| Nov 2025 | ENGINE | This is the 3rd catastrophic engine failure since purchasing this new vehicle from the dealership, the vehicle is currently at the dealership and is available for inspection. The latest diagnostic report has been attached from the dealership for reference. My safety and the safety of others was at risk with each occurrence. The 1st occurred on the interstate when a lifter rod bent causing loss of power with no warning, engine was rebuilt by the dealership. The 2nd occurred on the interstate when a different lifter rod bent causing loss of power with no warning, engine was rebuilt again by the dealership. The 3rd occurred just recently while on a highway. The engine suddenly turned off with no warning. The dash told me to put it into neutral and start again. I had to coast the truck for a long distance after the sudden loss of power in order to attempt to restart the engine. The engine would not start. The diagnostic report from the dealership states "engine is seized tight, maxi fuse is blown, needs engine replacement." | Crash: No Fire: No | Unknown |
| Nov 2025 | POWER TRAIN,SERVICE BRAKES,ENGINE | First my torque converter went out, no warning lights only shaking wehn shifting, I got it replaced already it cost me 2400 Second Warning light service for Brakes, Traction and power steering come on and off. And sometimes truck doesn't brake well and steering wheel feels hard to drive, it has happened while on expressway with family. Third Engine oil low Add oil warning sign comes up alot and I have to add oil, engine has a rough idle now, also when I turn truck on smoke comes out while having a rough idle, recently it started knocking, I haven't moved the truck since than | Crash: No Fire: No | Unknown |
| Nov 2025 | ENGINE | This is a report on an incident that happened a year ago. Vehicle was taken to GMC dealer who replaced the engine at our expense. Seems to be consistent with the problem on newer GMC's that have been covered by a recall. This 2020 is one of three GMC's owned by our company. This expense was in the $12,000 range. (The 2019 experienced similar issues in 2022 and the expense was $2800 ish, and in 2024 another $1200 ish. ) Dash lit up like a Christmas tree, all warning lights on. Stalled, barely moved. | Crash: No Fire: No | Unknown |
| Nov 2025 | ELECTRICAL SYSTEM,UNKNOWN OR OTHER,FUEL/PROPULSION SYSTEM | 1. The vehicle’s emissions system is malfunctioning, specifically the ECM (Engine Control Module) related to the exhaust emissions system. The diagnostic trouble code is P2C7A, indicating the system is not performing as expected. Key components such as the NOx catalytic converters and diesel particulate filter have been repeatedly replaced, but the issue persists. The vehicle and all replaced components are available for inspection upon request. 2. The malfunctioning emissions system has led to an exhaust leak that allowed exhaust gases to enter the vehicle’s cab. This creates a hazardous environment for both the driver and passengers, exposing them to harmful exhaust fumes. In addition to reduced engine performance, poorer fuel economy, and emissions non-compliance, this exhaust leak poses a serious safety risk by compromising the air quality inside the vehicle. Prolonged operation under these conditions could lead to adverse health effects and further mechanical failures that impact vehicle safety. 3. Yes. The dealership has diagnosed the problem multiple times. The emissions components have been replaced under warranty on two separate occasions. The dealer attributed the fault to fuel quality; however, Fuel distributor debunked these claims. 4. The vehicle has been inspected extensively by the dealership with invoiced repair work replacing key emissions control components. 5. The check engine light and Service Engine Soon (SES) light have been illuminated with the diagnostic code P2C7A since the initial identification of the problem which started 3JUN24 | Crash: No Fire: No | Unknown |
| Nov 2025 | ENGINE | Engine ticking especially when cold, dealership claims they fixed it while it was under warranty but it has continued to do it. | Crash: No Fire: No | Unknown |
| Nov 2025 | ENGINE | At approximately 54,000 miles had a complete engine failure. Lifter blew apart and damaged crank shaft. Complete engine rebuild. Rebuilt in approximately 3 weeks. 2022 At approximately 138,000 miles had another complete engine failure. Lifter blew apart again, Entire engine was replaced. New engine took 10 weeks to get. Installed in 2 days after recieved. 2025 No symptoms or warning lights present prior to failure. | Crash: No Fire: No | Unknown |
| Nov 2025 | ENGINE | Engine knock, loss of power, engine failure warning, ticking | Crash: No Fire: No | Unknown |
| Nov 2025 | POWER TRAIN,ELECTRICAL SYSTEM,FUEL/PROPULSION SYSTEM | Coolant control valve and engine cooling fan | Crash: No Fire: No | Unknown |
| Nov 2025 | ENGINE | While driving at highway speed and attempting to pass another vehicle, I experienced an engine failure; loss of power, noise from engine, and numerous warning messages on the display. At the GM dealer, I was informed that a pushrod (cylinder #2) was bent, the source of the engine noise. Upon further inspection (removal of cylinder heads), it was determined that the cam shaft chrome had begun to flake causing pitting (lobe damage) which in turn caused the pushrod to fail. Had the pushrod broke instead of bent at highway speed, I feel there would have been a catastrophic failure with more severe consequences for my vehicle and others around me. Vehicle was diagnosed and repaired by a certified GM dealer. There were no prior warnings/indications of problem(s). I understand there is a current recall of the GM 6.2L L87 engine for model years 2021-2024. This incident occurred on a model year 2020 GM 6.2L L87, but the issues I experienced are identical to the 2021-2024 engines identified in the recall. | Crash: No Fire: No | Unknown |
| Nov 2025 | ENGINE | I experienced lifter and camshaft failure on my 2020 GMC Sierra equipped with the 6.2L V8 engine at approximately 72,000 km. GMC denied warranty coverage as my factory warranty had expired only four months earlier. The repair cost me nearly $10,000 out of pocket. My vehicle has been meticulously maintained with regular oil changes performed at my local GMC dealer every 5,000 km, and it has always been fueled with premium gasoline as recommended by the manufacturer. The engine failure was sudden and unexpected. All lifters and the camshaft were replaced during the repair. Since the repair, I have noticed intermittent RPM fluctuation under light load conditions. I am currently working with my dealer to diagnose whether this issue is related to the recent engine repair or a transmission flush that was performed at the same time. I am extremely disappointed in GMC’s handling of this situation. Despite this being a well-documented issue with the 6.2L engine, I received no goodwill assistance or warranty consideration from GMC. While my dealer provided a partial discount on parts and labor, I was still responsible for nearly the entire repair cost. I hope GMC and NHTSA will review this matter closely, as owners should not be facing such expensive failures on well-maintained vehicles with this engine. | Crash: No Fire: No | Unknown |
| Nov 2025 | ENGINE | A lifter in my cylinder is bad and damage to my cam shaft. This truck also has the 6.2L engine that was recalled for other GMC Vehicles.My safety was put at risk as I was driving it and it started smoking. I have had 2 different mechanics look at it. One mechanic was an independent business, the other was a certified GMC dealer. There was no warning lamps or messages. | Crash: No Fire: No | Unknown |
| Oct 2025 | ENGINE | Rod bearings spun and engine locked up while driving 70mph on the freeway. I was in traffic, and had to work my way over and off to the shoulder of the road. The engine was diagnosed and replaced by Hiley GMC at a cost of nearly $5,000 out of my pocket. This was at approximately 63,000 miles. Just out of warranty. No loaner vehicle provided. I was without my truck for 2 months. There were no warnings at all. No lights or noises of any kind. Rod bearings spun again on the replacement engine approximately 35,000 mile later. It happened same as before. Driving on the freeway at 70mph, and the engine seized. No power steering, no warning noises or lights. I had to coast across lanes through traffic and onto the shoulder. Diagnosed and replaced by Jerry's GMC. They replaced the motor at no charge except I had to provide the new radiator because it was on backorder. They had the truck for over 3 months and I had no loaner vehicle. With approximately 65,000 miles on the latest engine, a lifter went out. I put it in the shop to have all the lifters replaced, and motor mounts replaced at a cost of $6500. Upon taking the truck for a test drive, the engine seized in traffic under an overpass and blocked one lane of traffic. The shop dropped the oil pan to check it out, and, lo and behold, this engine has spun rod bearings again. There is definitely a serious and dangerous problem with the L87 6.2L. Being a 2020, it is not currently included in the recall, but it needs to be included. I spun bearings the first time in August of 2021. I was hoping it was just bad luck. I hadn't heard of all the instances at the time. I've never had a major engine failure prior to this model, and this one has failed 3 times in the same truck with meticulous maintenance. | Crash: No Fire: No | Unknown |
| Oct 2025 | ENGINE | The check engine light went off and started blinking. The engine started making ticking noise. I pulled over. The check engine light kept blinking. I had the truck towed to the Chevy Dealership. They found damage to the lifter and camshaft. They had the truck for over 2 weeks. Luckily I purchased the extended warranty. But the repair still cost me 1,200.00 dollars out of pocket. And cost the warranty company over 9,000.00 dollars | Crash: No Fire: No | Unknown |
| Oct 2025 | ENGINE | The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving 55 MPH, the vehicle failed to accelerate as intended while depressing the accelerator pedal. In addition, there was an abnormal sound coming from the engine. Multiple warning lights were illuminated. The contact was able to coast to the side of the road. The vehicle was towed to the dealer, where it was diagnosed with engine failure. The engine was repaired. Most recently, while driving 35 MPH, the vehicle failed to accelerate as intended while depressing the accelerator pedal, with an abnormal sound coming from the engine. Multiple warning lights were illuminated. The vehicle was towed to the dealer, where it was diagnosed with engine failure. The contact was informed that the camshaft, bearings, and lifters in cylinder #4 had failed. The vehicle remained at the dealer unrepaired. The manufacturer was notified of the failure. However, no assistance was provided. The failure mileage was approximately 19,000. | Crash: No Fire: No Towed | 19,000 |
| Oct 2025 | ENGINE AND ENGINE COOLING | Tick sound coming from underneath. Also fumes smell. Dealership found it to be the exhaust system. Said the muffler valve is bad. Quoted me $2000 for repair. Never heard of a exhaust system failure in only 5 years. Very unsatisfied with this. | Crash: No Fire: No | Unknown |
| Oct 2025 | UNKNOWN OR OTHER,ENGINE | I heard a ticking noise coming from the engine compartment. I took it to the dealership that I purchased the truck from and that have been using consistently for service. I was told that the noise was coming from a lifter on the driver's side of the engine and, on further investigation, it was determined that the camshaft had been damaged. I was told that it could seize up as I was driving and that my safety and those with and around me would be at risk. At 85,000 miles, the engine had failed and would have to be replaced. There was no prior warning or no check engine light and the vehicle has been in for oil changes and all maintenance at the dealership. The new engine cost me $15000 including diagnosis and towing. | Crash: No Fire: No | Unknown |
| Oct 2025 | ENGINE | I noticed a ticking sound in my 2020 GMC Sierra 1500 SLT 5.3 Liter on 10/15/2025 after it was serviced at an Authorize Buick GMC Dealership on 10/13/2025. I made an appointment and returned the vehicle to the dealership for further inspection on 10/17/2025. I was informed later that day that my truck has lifters and camshaft failure. If my truck had stalled or stopped on the express way, myself and others safety could have been at risk. My truck has only been looked at by the dealership at this time, and it is available for inspection upon request. There were no warning lights, check engine lights, messages or symptoms prior to the failure. I did get a low oil level message in April 2024 when the dealership stated they must not have put the correct amount of oil in my truck during an oil change on 1/29/2024. They inspected my truck and assured me there was no damage done to my Engine from this issue. I have recently learned there is a recall for GM Vehicles manufactured between 2021 and 2024 with the 6.2L engine installed. I am not sure why this recall does not include 2020 trucks with the 5.3L engines installed. Apparently, the same problems exist with these engines also. I received an estimate for repair approximately $13,000 which can increase once the engine is town down and inspected further. Any assistance you can provide would be greatly appreciated. | Crash: No Fire: No | Unknown |