While driving in Southern Utah my truck gave me a Service ESC (Electronic Stability Control) Warning, Service Parking Brake Warning, and check engine light that was for code P0303. I had the vehicle towed to the local Chevrolet dealership and it was diagnosed with lifter failure and camshaft damage because of the lifter failure. Safety was compromised because of the failure of the ESC and the loss of power and stability of the engine. I didn't receive warnings prior to the failure. This appears to be a well-known issue with several service bulletins issued for the vehicle.

- Fort Worth, TX, USA

After three oil leak repairs in my LM2 3.0 diesel engine in my 2020 Chevrolet Silverado RST, you would think that would be enough to repair the manufacturer's defects, but it wasn't. I think the saying is fourth time is the charm? The third repair which was a second oil pan lasted a whopping 48 hours before leaking. This time it ended up being the timing chain cover that was leaking. Again, the service advisor mentioned that these are known to leak too due to a defect from the manufacturer. I even got a call from the service manager, and he said that anything area that could and does leak oil on these LM2 engines has been replaced and/or repaired, so I should be good for the future. I called into GM as per their instructions to update them on the fourth oil leak, and where the repairs were taking place. Fast forward to nearly two months later, and no one from GM attempted to contact me, and Jill stated that the case was closed and wouldn't disclose why. The only thing she could do was open another case. I declined since GM couldn't be bothered to address the issues they know they have in the LM2. The dealership the work was done in, the service advisors, the service techs, and the service manager all discussed in great detail the issues Chevrolet is having with the 3.0 diesel engine. GM knows this and refuses to address this. At this point, my vehicle spent 37 days in 2.5 months at the dealership fixing oil leaks that at any time could have caused engine failure and resulted in a crash. This truck is our dedicated family vehicle as my wife and I each daily Subaru WRX's. GM has done nothing and will do nothing. Someone needs to issue recalls to address the oil leak issues with the LM2 before it results in someone's death. I wish I wouldn't have wasted time contacting GM. I should have filed these complaints and got legal representation for the Magnuson-Moss Warranty Act. * loaner vehicle was given during the entire 37-day repair duration.**

- Woods Cross, UT, USA

The second oil leak repair and the first repair for the oil pan failed within one week of the previous repair. This is the third oil leak that occurred in the LM2 engine in the 2020 Silverado. It was identified as an additional leak in the oil pan which had already been repaired the week prior. This is a failure within seven days from the previous repair. I lost 1/2 quart of oil during a 650-mile drive back from vacation. I took pictures of the oil level before leaving and driving home. During our drive, we passed through an area called Yermo where it was 107 degrees at 11am. The two closest Chevrolet dealerships are either 45 minutes or 1.5 hours one-way. I was incredibly frustrated since imagine being stranded in 107-degree weather with your family on the side of the road unable to run AC. It is a serious life, health, and safety issue at this point. I called GM and opened a case expecting them to assist me with the issues with the truck. Fast forward to today, I spoke with Jill at GM, they closed the case without even reaching out to me. This was the third of four oil repairs that have been conducted on my vehicle and the LM2 engine. It isn't a safe engine to have. * loaner vehicle was given during the repair.**

- Woods Cross, UT, USA

This is for the second oil leak that occurred in the 2020 Chevrolet Silverado with the 3.0 diesel engine. It was identified as a leak in the oil pan. The previous repair was for the lower crankcase seal. The service advisor at the dealership stated this is another problem area with the Chevrolet 3.0 diesel engine, and a defect from the manufacturer. He also mentioned it is a common repair they complete on these LM2 engine. It is worth noting, the initial repair didn't last 60 days before another oil leak presented itself. This is the second of four repairs that were done on this vehicle. * loaner vehicle was given during the repair.**

- Woods Cross, Ut, UT, USA

There was a significant oil leak that was diagnosed during a routine oil change in March of 2025. The dealership that identified the leak attempted to pass it off as something that was out of warranty even though the vehicle had an additional six months and 45,000 miles of warranty (3.0 diesel). The leak was significant enough that loss of oil could cause the engine to fail and result in a crash. Subsequently, another dealership identified the leak and repaired the seal around the lower crankcase. It did not repair the oil leak- there are three additional reports/complaints to file.

- Woods Cross, UT, USA

Motor suddenly loss power and load knocking noise. After taking it to the dealer they said that number 3 cyl.connecting rod had an issue. This sounds like the same recall for the 2021 to 2024 6.2 engines. They gave me a quote for a new engine ( 20000) that was not available for 4 to 5 weeks if not more. I was on vacation at the time and ended up buying a new truck from them. I was not happy.

- Riverside, CA, USA

Having failure with the engine coolant control valve. Have taken my truck to the dealership for overheating and they always come and say that they can-??t find an issue. They also informed me that I need to bring it back when my motor blows a head gasket which is complete bull.

- Greensboro, MD, USA

Lifter failure on the 5.3L L84 engine. Due to Dynamic fuel management that come with the trucks.

- Austin, TX, USA

About 3 months after the 5 year 100000 mi warranty with only 70000 miles on the duramax diesel engine the exhaust brake part of the engine emissions/exhaust split along the weld. Have seen a number of these reported on the internet as well. Sounds like a manufacturing problem. The vehicle's check engine light came on and it's now at the dealership getting a new exhaust brake housing and bracket replaced. If this was in California or the 12 states listed would be covered for 8yrs/100000 miles.

- Barboursville, VA, USA

Engine seized my truck has been at the Chevorlet Tempe dealership I filed a claim with GM still no response.

- Phoenix , AZ, USA

My 2020 Chevrolet Silverado 1500 LT with the 3.0L Duramax diesel engine has experienced three separate failures of the coolant control valve over a span of less than two years. Each failure resulted in the vehicle entering reduced engine power mode, which drastically limits acceleration and the ability to maintain safe driving speeds -?" particularly dangerous on highways or in heavy traffic. Chronology of Failures: October 2023: First coolant control valve failure. Part was backordered. Repair took ~6 weeks. June 2024: Second failure of the same part. Another 6-week delay in repair due to part availability. June 2025: Third failure of the same part. Vehicle is currently inoperable and unsafe to drive. Each time, the failure triggered a check engine light and immediately placed the truck into reduced power mode. This issue significantly compromises driver safety, especially in high-speed or congested environments, where limited acceleration can increase the risk of collisions. Safety Concerns: Loss of acceleration power at critical times (merging, overtaking, etc.) Unpredictable vehicle behavior Extended unavailability of parts leads to prolonged periods without a functional vehicle Possible underlying design flaw or recurring part defect Given the recurrence, safety risks, and the number of similar complaints I have seen from other owners, I believe this is a widespread and systemic defect that deserves NHTSA investigation. Requested Action: I urge the NHTSA to investigate the frequency and root cause of coolant control valve failures on the 3.0L Duramax engine in the 2020-?"2022 Silverado models. This is not an isolated incident, and repeated failures of a critical engine cooling component warrant a safety recall or technical service bulletin (TSB) requiring redesign or replacement with a permanent fix.

- Edmond, OK, USA

Lifter failure and miss fire

- Zimmerman , MN, USA

I was driving and came to a stop at a red light. When accelerating on green the transmission would not go into gear, stalling my vehicle. Nearly causing the vehicle behind me to rear end me. The vehicle eventually went into gear and started to slowly accelerate with shuttering of the transmission.

- Tucson , AZ, USA

While driving my truck the engine completely shut down. All the dash lights came on initially but then only the check engine light stayed on. My truck never would start back up after that. It was towed to GM dealership who diagnosed catastrophic engine failure.

- Elgin , OK, USA

Was driving on the interstate on [XXX]. While driving, the truck suddenly slowed down and lost power. The check engine light came on and then after about a minute a message popped up on the dash saying that the truck was in reduced-power mode to prevent engine damage, or something like that. It slowed to roughly 50mph and I had to drive for maybe 5 miles to reach the next exit, narrowly avoiding collision from behind with cars driving upwards of 75. Pulled off the road to the first parking lot, then got towed to the nearest Chevy dealership in Shawnee, Oklahoma. The diagnosis was a blown connecting rod that had occurred while driving on the interstate, resulting in a necessary total engine replacement. The truck was repaired in Shawnee, Oklahoma at the dealership. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- San Angelo, TX, USA

2020 Chevy Silverado LTZ 6.2 V8 10 Speed. Started having issues with hesitation/shudder. Dropped off at a Chevrolet dealership for a diagnostic. The dealership pointed to a potential transmission issue. After having the truck for several days, they reported nothing wrong. Said they drove the truck, checked the transmission fluid, and couldn't find any issues. Picked up the truck and took it to a local repair shop. That shop drove it, but could not re-create the issue I was describing. I opted to have the transmission fluid flushed in hopes of fixing the shudder/hesitation I was feeling. After picking up the truck and driving it a couple hundred miles, the issue was still present. I made another appointment at the same local shop. This time, they called me saying the issue I'm feeling is the same problem that's been happening to these engines, the dreaded AFM (Active Fuel Management) system is starting to fail. I was told by the shop it's only a matter of time before the entire engine fails. The only way to fix the issue is to delete the AFM system by removing the old parts within the engine and replacing with new parts that do not use the AFM system. This would cost approximately $6,000 to complete.

- Augusta, GA, USA

Was driving on highway and vehicle went into "engine power reduced" and dropped from 60mph down to 35mph and then steadily decelerated down and wouldn't go over 18mph. Per mechanic it is the engine coolant control valve and the part is not available and could be months to a year before the part is available. Online shows this is a widespread issue with GM / Chev vehicles but no recall has been ordered and parts not available anywhere. Completely unacceptable to pay $65000 for a vehicle that is just barely 5 years old and have this kind of issue and manufacturer doing nothing about it.

- Chesapeake , VA, USA

When a Check engine light is on it's for a low voltage on the charge air coolant sensor, took to the chevy dealer, they replaced a connector to the sensor, at a cost of $600 never got off lot, light returned, they then said I need a new engine wiring harness at a cost of $100, the dealership said this is a problem with these trucks and GM knows about it but won't recall them. Now I'm struck with a 5-year-old truck that I can't use, When this light is on, I also receive an Emission system warning, and the truck deregulates and goes in limp mode. as speed is reduced it becomes dangerous to drive in traffic, as GM knows about this, they should recall these trucks and fix the problem, they even say it's because cutting corners on the wiring harness cover causes this problem. as a senior living on a fixed income there's no way my wife or I can get this repaired, so were forced to drive it in limp mode until it dies on us, hopefully not in heavy traffic.

- Orlando, FL, USA

Oil pump went out. Got it repaired. Then, a few days later, while driving on the freeway at 70MPH the engine made a lot of noise then quit in middle of the freeway leaving me vulnerable to being hit. Was able to coast in neutral to the edge of the road. Has 73000 miles on it. Dealer says I need an engine replacement after just spending $5,500 for oil pump replacement. Has been at the dealer over a month and no replacement engine is available.

- Aloha, OR, USA

The engine seized up. Yeah, the truck is at a trusted mechanic and he told me that the engine seized. No warning signs. The truck wouldn't start and the engine light was on.

- Big Sky, MT, USA