I have had no issues with my vehicle since I purchased it in July 2022 and keep up with the routine maintenance on it. About 2.5 weeks ago I was driving to work like I normally do and the truck started making a knocking noise and all these sensors lights came on the dash. The alerts were saying to service the parking brake, service ESC, and that steering assist is reduced and to drive with care. The vehicle also started shaking and would not accelerate properly or shift gears. We ended up taking it to the closest GMC dealership and they were in able to diagnose it just by simply hooking it up, they had to fully dismantle the engine in order to diagnose it. They came back and said cylinder number 4 is damaged as well as the lifters and cam shaft. I am no car expert but it is weird that a car that is relatively new and has the maintenance kept up on it should not experience a serious malfunction like this. What is even weirder is my sister in law has a 2020 Chevy Silverado where the almost identical thing just happened to theirs and it too is now in the show as well needing its engine and stuff repaired.
2020 GMC Sierra 1500 engine complaints
Page 9 of 10: complaints 221 to 250 of 260, newest first, as owners wrote them.
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving 80 MPH, the vehicle lost motive power and stalled. The vehicle regained power within seconds and the contact was able to continue driving. There were no warning lights illuminated. The contact stated that the failure reoccurred. The vehicle had not been taken to the dealer to be diagnosed or repaired. The manufacturer was made aware of the failure and confirmed that there was no recall on the VIN for the failure. The failure mileage was approximately 50,000.
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 the federal safety agency 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.
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.
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 .
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.
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)
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 federal safety agency Hotline to report the failure. The vehicle was not repaired. The failure mileage was approximately 40,000.
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.
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.
The contact owns a 2020 GMC Sierra 1500. The contact stated that while the vehicle was parked and being driven, the vehicle was shaking violently. There were no warning lights illuminated. The contact stated that the failure was related to Technical Service Bulletin: 22-NA-186. The vehicle was taken to a local dealer, where it was diagnosed that the motor mount brackets needed to be replaced. The vehicle was repaired, but the failure persisted. The manufacturer was contacted, opened a case, and referred the contact to the federal safety agency Hotline for assistance. The failure mileage was approximately 100,000.
The contact owns a 2020 GMC Sierra 1500. The contact stated while driving at various speeds, the vehicle was stuck in gear. While driving there was an abnormal burning odor coming from the vehicle. The vehicle failed to start on several occasions. There were sparks from the passenger's side front seat. Several unknown warning lights were illuminated. The vehicle was taken to the local dealer, where it was diagnosed with electrical, transmission module, wiring harness, air alternator cooler, and exhaust system failures. The vehicle was repaired; however, the failure recurred. Additionally, while driving at undisclosed speeds, there was a failure with the vault meter. The OnStar system provided an error with the antilock braking system. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 44,000.
My wiring harness which affects all systems. I was on the Interstate when out of nowhere any and all warning lights came on. The power was cut and rapidly slowed down. I also pulled into traffic and the truck just lost power. The problem was confirmed by dealership. The vehicle was inspected by dealership and wiring harness was the issue. The issues appeared out of nowhere. All the warnings lights came on at once. There has been numerous issues with this part and it’s even recognized by just.
See attached document for complaint
Vehicle has excessive oil consumption. Within 5000k oil change interval, no oil on dip stick around 3000k miles.
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)
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.
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.
Camera always stays on even when i am driving camera still on my dashboard
Diesel exhaust fluid heater short circuits due to poor design. This issue occurs multiple times, including after being repaired. The failure limits the trucks capabilities until it is entirely unusable.
Vehicle engine went out on truck.
A very strong "ammonia" odor comes into the cabin. This happens when the def fluid is going into the exhaust system for the regen process. The odor makes people inside nauseous and dizzy. Must open widows or stop and get out of the vehicle. Our gmc dealer can find no codes or problems with the exhaust system. We have also noticed that the def fluid has gone down very quickly sometimes during this event. It is random. Some days nothing, other trips 3 and four times that the odor occurs. Looking online- there have been many post about this problem.
I have a lifters problem that the dealership takes more that three weeks to fixed without a loaner car, then i have electrical problems where the truck doesn't start at all without any warning and that's it's dangerous, never now where its going happen
The contact owns a 2020 GMC Sierra 1500. The contact stated that shortly after refueling while driving under 15 MPH, the check engine and service emissions warning light illuminated. The contact stated that an unknown reset was performed related to TSB: 10173675 (Engine). The vehicle was not yet fully repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 46,000.
Two times while on the freeway the service parking brake and engine lights came on and starting braking. Could not drive over 20 mile an hour. Both times taking to dealer the lights where not on and they could not find anything wrong. I even have video of it happening.
Repeated issues with exhaust and emissions components.
Found improperly installed rear seals. The truck leaked oil and had to be towed to gmc dealership in Monahans Texas to be repaired. 1 month later the truck leaked oil again.
Rear main oil seal failure causing truck to lose all oil, leaking all over truck, trail leading to drive and garage; possibility of engine seizing up while driving causing an accident, confirmed by dealer, covered by warrenty, is a known issue, no warning lights, messages, or other symptoms of problem, NHSTA has issued a bulletin for this problem
On Saturday, May 22, 2021, My wife was returning from fairgrounds in Waxahachie, TX. She remote-started the car, and the vehicle started. As it started to rain and was getting muddy, and the grounds are in a grass field (No large rocks, hills or debris to climb as it's cleared land), she shifted the vehicle into 4wd high incase the field was slick. She started to drive and received several warning lights, "Service ESC, Service traction control, brake light warning and check engine light". The vehicle also had a noticeable wobble to the wheel and felt off balance, jerky, and had speed limited. My wife turned the vehicle off and back on and some of the lights went off, and the vehicle did not lurch or wobble anymore. The vehicle had a tire changed at the dealer the day prior, so I am unsure if that tire change is related or not. Now the vehicle shows an alert "check engine, service emissions system". I am having the vehicle towed to the dealership tomorrow for diagnostics. All lights except the check engine light have since turned off since powering off the vehicle.
At about 3500 miles lifters on two cylinders colasped. Took to dealer that dealer had three weeks but fixed it. 1500 miles later at 5036 miles it happened again on a different cylinder. Number 8. The first time it was 3 and 5. The first time the dealer replaced all 8 cylinders. So cylinder number 8 was new as well. Gmc has said there is nothing else that can be done to fix the issue. The second dealer service manager states that he would not trust it either to go any long distance . Also stated that they have put 3 sets in to one vehicle before. As an ase master certified technician I find this disturbing. I also was a gmc,pontiac, oldsmobile master technician. This is unexceptable for gm to think this is ok to take people's hard earn money and not fix there issues or make it right. I owned a 2014,2016,2018 silverado's that had no issues what so ever. To make things worst gmc road side assistance forgot about the truck broke down in 7 degree weather with 35 mile an hour winds. For over 24 hours and several calls back to finally get a supervisor to speak to. Two dealers say that it is unacceptable except the current dealer that is dealing directly with gmc. Anyone can do a search on gm truck lifters collapsing and you immediately overwhelmed with info. It is also disturbing that a dealership service manager says we could put a new engine in and the same thing could happen. That to me is poor quality control and poor customer service. I have always been a gm enthusiasts but this will be my last one. Horrible customer service and do not build a good product or stand behind it. Gm should be ashamed of there fall from grace. This all happened just driving once to work and once hauling a atv on a trailer.
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