general problems of the 2023 GMC Sierra 1500 - part 1

The contact owns a 2023 GMC Sierra 1500. While driving at 30 mph, the vehicle jerked and lost motive power. The vehicle was restarted and driven at reduced power to the dealer, where unknown electrical repairs were performed. The failure persisted, and the vehicle was towed to a second dealer, grissom Chevrolet (181 s interstate 20 frontage rd, pecos, TX 79772), who replaced the engine. However, the failure recurred, and the vehicle was towed back to the first dealer, who diagnosed that the spark plugs and other unknown parts needed to be replaced. After the dealer performed the unknown repairs, the check engine warning light illuminated when the contact's son-in-law picked up the vehicle. The contact's brother, an independent mechanic, diagnosed that the catalytic converter and other unknown parts needed to be repaired. The contact filed a lemon law claim. The manufacturer was notified of the failure by phone. The failure mileage was approximately 50,000.

It is a 23 GMC sierra denali has the l87 [xxx]. 2 with 43,000 miles an blew up yesterday while on vacation in [xxx]. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

1) driving on highway and lost acceleration power would only go 50 mph/went into limp mode. Dealership stated VIN number had not been released into national safety recall. Replaced crank shaft valve and was told once VIN was released I would be reimbursed, to date still in dispute. 2) low oil light came on, upon checking oil was extremely low and oil had just been changed during #1’s repair. Had towed to dealership. Engine was replaced under recall. Was charged for water pump which is in dispute. 3) shortly after and well before oil change would be due, low oil light came on again. Towed back to dealership dip stick bone dry. I asked the store vehicle inside. Called for diagnosis at 5pm stated no codes no leaks found needed to investigate further. 4) 9am following day received a vm the truck had been repossessed by gm (note there is only 10k remaining on a special order 72k truck) dealership has not responded to requests to determine if the issue was fixed or request for service ticket to know what had been done. Gm financial claimed dealership told them it “was just a part under warranty” well the warranty came from the replacement engine that was under the recall…upon talking to reinstatement dept I was informed the vehicle was not fixed. I will be redeeming the vehicle but I do not think it is right to repo during a safety recall and then auction off not fixed as that is a safety issue! once redeemed, it is also a safety issue to get from auction lot to be repaired.

6. 2l engine lost power and failed at highway speed with no warning lamp or prior indication of failure. Engine recall/pico test and oil viscosity change performed by dealer at 40,000 miles. Engine failed at 45,868 miles.

Code p1098 came up today 80k on the truck. Coolant control valve failure. Second time this has failed, first at 45k. Speed reduction activated.

The contact owns a 2023 GMC Sierra 1500. The contact stated that while driving 70 mph, the engine seized, causing the vehicle to stall and lose motive power in the middle of the interstate. The vehicle was unable to restart and was towed by onstar service. The vehicle was towed to the dealer, where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was scheduled to be repaired by the dealer. The manufacturer was made aware of the failure by the dealer.

Addendum to previous submission # 11760415. At 15,033 mileage again multiple codes present along with a rough running engine. Dealership service dept confirmed on 9/17/2026 verification of 10 active codes , 2 pending codes triggering check engine light. Onstar notification as well of engine issue. Prominently codes p0016 & p0340 lead the list. Pico testing was stated to have failed two out of 3 parameters. Officially stated now as an engine defect which is being directed to be replaced with a remanufactured , not new , motor. Very fortunate to not have experienced dramatic failure ( loss of propulsion ) at highway speeds far from home. Even though this vehicle warning's persisted prior to this ultimate conclusion it was insisted that ultimate failure was necessary before any resolution would be instituted. A safety conundrum if you will. A high probability safety risk of continued use ( based on historical data on this known engine failure risk ) to ‘ prove ‘ it would fail like many others already have. A fair assessment of my personal experience.

On 9-10-26 engine spun rod bearings per the dealership repair order miles 52,796 I was towing a car on a car trailer traveling down the interstate when the motor failed. I had my wife in the truck with me. No prior warnings just a check engine light right before engine failed. GMC dealer replaced engine and returned on 9-14-26. The truck had already had the recall to check the engine and replace the oil to a thicker oil.

The contact owns a 2023 GMC Sierra 1500. The contact stated that while driving 65 mph, the engine made a clunking, knocking, and tapping sound. The engine was driving on seven of the eight cylinders. The contact slowed down and pulled over. The engine warning light was illuminated. The vehicle was taken to the local dealer and was diagnosed with a detached valve. The vehicle was repaired under an extended warranty. The dealer informed the contact that the failure might recur. The failure mileage was approximately 12,998.

A 6. 2 engine operated as expected for 75,000 miles. I turned a corner at an intersection, and had a loud knocking in the engine occur. For the first 75,000 miles, there wasn't any unusual engine noises or oil consumption. Seconds later the engine light illuminated on the dash, reduced engine power, and every safety light within the dash was going on and off. I managed to drive slow and return to my residence and have the truck towed to the dealership to have the engine replaced. As many have learned, the recall from gm states to either pass a pico test and change to 0w-40, or have the engine replaced if necessary. My concern is that the replacement engine is the exact same engine with the exact same components that assuredly will fail due improper design, production, and overlooked components that attribute to such failure. The crankshafts are being found to have values of "peaks and troughs" within the finish that are many times out of given specifications. The extraneous pressures created by the dynamic fuel management system over time are creating stresses and friction that the designated oil and oil pump are not compensating for. These mechanical stresses over different durations, seem to be part of the cause of the engines failure. The replacement engine came with a warranty that only extends to an odometer reading of 150,000 miles. I no longer have confidence in a manufacturer that is enforcing false resolve upon a customer as a solution. The new engines of replacement have been failing as well. This result exhibits a fact that shouldn't be ignored. The new engines have the same components and are due to fail, just the same as the original. I would like the manufacturer to resolve this failure by offering a "true" solution. A proven remedy and a documented warranty that assures the manufacturer stands behind the product. Gm sells a new product that fails and then recalls the engines to replace with the same failed components and lack of warranty.

I am reporting a serious safety concern involving a 2023 GMC Sierra 1500 denali, 6. 2l l87 v8, VIN [xxx]. This vehicle has now experienced two catastrophic powertrain failures at very low mileage. The first catastrophic engine failure occurred at approximately 23,696 miles. The vehicle was taken to a GMC dealer, where the repair documentation states that the engine had suffered significant internal damage, including damage to the #3 connecting rod, a missing connecting-rod bearing, bearing material throughout the engine, and a scored crankshaft. The dealer determined that the engine was seized and required replacement. Gm replaced the engine under warranty with gm engine assembly part number 12740076. The vehicle has now experienced a second catastrophic failure. On [xxx], while traveling approximately 40 mph, experienced grinding, lurching, and knocking, followed by a complete loss of propulsion. The truck would no longer move and had to be towed to a GMC dealer. At the time of the incident, no warning lights or warning messages were observed. The transmission is also suspected to have failed, although the exact cause and extent of the transmission failure have not yet been determined by the dealer. I understand that NHTSA is currently investigating failures involving gm 6. 2l l87 engines, including failures occurring after previous recall remedies and engine replacements. I am therefore requesting that this incident be included in NHTSA’s investigation and considered when evaluating the effectiveness of the existing recall remedy and the safety of replacement l87 engines. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

My wife and I were driving on the highway going slightly uphill. I pushed the pedal a bit because the power wasn't keeping speed. It continues to not maintain so pushed throttle further and the truck stalled. We traversed 3 lanes to get to the shoulder. When I stoped I tried to restart but the car wouldn't turn over but all electrical were working. We were on the shoulder for over and hour on a main highway. We had aaa tow it to the dealership where they confirmed the engine was seized and will be ordering parts. The car is still available upon request. Our safety was at risk from loosing power on the interstate and sitting on the shoulder is very dangerous. I didn't receive any warning lights prior to this occuring. The truck did undergo the peko test and passed and added new oil viscosity. It had roughly 55k miles on it. Always changed the oil before it hit 0% oil life as told by dealerships.

Sudden loss of propulsion while driving on I-75 with cruise control engaged. Vehicle began to decelerate. Pulled off onto emergency lane. Engine was idle-ing roughly. Would not increase rev when gas pedal pressed. Shut down. Tried one restart. Unsuccessful.

Driving on I-75 with cruise control engages. Vehicle began decelerating. Pulled over onto emergency lane. Engine idled roughly. Shut down. Attempted one restart unsuccessfully.

The engine made a noise and it seems to me that this engine will loose power and leave me in a situation that could cause an accident or breakdown in the middle of a bad situation. I don't trust this truck and its engine and I refuse to drive it now.

During a family camping trip, our engine seized without warning — a failure directly tied to an active GMC recall. Despite this being a manufacturer defect, GMC roadside assistance refused to provide full support and informed us that we were responsible for towing our trailer home. This placed an unreasonable financial and logistical burden on us during an already distressing situation. To make situation worse when we brought the vehicle to o’meara GMC for the recall repair four months prior. They kept our truck for an entire week, only to inform us that their “solution” was to put heavier-weight oil in the engine. This is not a recall repair. It is not a fix. It is a temporary workaround that demonstrates clear incompetence and an inability or unwillingness to replace the motor as required under the recall. O’meara GMC failed to perform the recall repair, failed to replace the engine, and failed to provide any meaningful resolution. Their actions have left us with a vehicle that is unsafe, unreliable, and not repaired according to GMC’s own recall standards.

The 6. 2 engine in my truck failed while driving and it has been determine that I need a new motor. This motor was on the recall list. I brought it in for the pico recall test in October we 2025 and it passed. They then changed the oil for a much more expensive 0w40. The engine failed in August leaving me stranded on side of the highway. It has been at the dealership since August 7th. There is no eta on when the new motor and parts will be available because I’m being told that some parts are on back order. I have looked into trading it in and the value of this truck due to the 6. 2 engine recall is significantly lower that it should be. It’s half of what I paid for it 3 years ago. I incurred towing fees and uber fees. I am no without a truck to tow with.

13 unresolved problem codes relating to hard engine starting,rough engine running,vehicle initiating safe mode operation, upon a highway trip. P0016 engine code detected and onstar messaged for immediate service. No resolution at dealership , after resetting codes an additional 9 are active / pending at 2nd dealership visit. Abnormal engine operation since , dealership advises a hard failure has to occur before a resolution can be instituted. Similar advice from GMC direct phone call in help line.

I, [xxx], am currently getting my engine replaced for the 1st time because of an engine failure. Engine completely shut down in the mountains while I had my 3 young kids ([xxx], [xxx] & [xxx] old) on our way to our vacation. 102 degrees outside no ac, no water for 4 hours until a tow truck finally came. The kids were scared for their life due to being on the side on the road, hungry with nothing to do but wait. Literally had just enough clearance to get on the side of road where vehicles drive-55-65 mph. Avenal, CA to be exact. What’s the best way to get my money back? I do not want to continue to deal with these problems on the road with my little ones. The dealership is currently looking to replace my engine and waiting on parts. There has not been an official date I will get my vehicle back. Thank you in advance. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Driving down the interstate at 70 miles per hour, started losing power, engine light came on. Engine started making a loud banging noise as I pulled onto an exit.

I own a 2023 GMC Sierra 1500 denali ultimate equipped with the 6. 2l l87 v8 engine. The vehicle previously experienced an engine failure that resulted in the complete replacement of the 6. 2l engine by an authorized GMC dealership. The replacement engine was installed at approximately 76,316 miles. After approximately 1,000 miles of driving with the replacement engine, at approximately 77,354 miles, the vehicle displayed a check-engine/service warning and experienced abnormal transmission shifting. I returned the vehicle to the GMC dealership for diagnosis. The dealer documented dtc p0747, identified as “transmission control solenoid valve 1 stuck on,” and recommended replacement of the transmission control valve body at a quoted cost of $2,665. 85 plus tax. The dealership has stated that this transmission condition is unrelated to the recent engine replacement. However, because the condition appeared only approximately 1,000 miles after a complete engine replacement, I have asked general motors to investigate whether the current failure could be associated with the previous engine failure, the engine replacement procedure, or other related vehicle systems. I have opened a case with general motors customer assistance and have deferred the customer-paid valve-body repair while gm reviews the matter. I am submitting this complaint so NHTSA/odi has a record that this vehicle experienced a major 6. 2l l87 engine failure requiring complete engine replacement and then, approximately 1,000 miles after that replacement, developed a check-engine warning, abnormal transmission operation, dtc p0747, and a condition requiring replacement of the transmission control valve body. I can provide the engine-replacement repair order, current diagnostic documentation, mileage records, dealer repair estimate, and gm case information upon request.

While driving, my 2023 GMC sierra with the l87 6. 2l engine experienced a sudden, complete, catastrophic loss of engine power. There were no warning lights or messages prior to the failure. This was a one-time event, but it left the truck inoperable and I have been without the vehicle since it happened. The vehicle had recently passed applicable recall checks and had a routine oil change performed, so it was properly maintained leading up to the failure. A sudden loss of engine power while driving poses a serious safety risk, including the possibility of a collision if it happens in traffic or at highway speed. It is unknown whether a dealer has confirmed the root cause, as the vehicle has been out of service since the incident.

The contact owns a 2023 GMC Sierra 1500. The contact stated that while driving approximately 40 mph, the check engine warning light illuminated, and an oil message was displayed. The vehicle stalled and was unable to be restarted. The vehicle was towed to a dealer where it was diagnosed and determined that the engine needed to be replaced. The vehicle was repaired, but the failure reoccurred approximately two weeks later. The vehicle was taken to a different dealer but was not yet diagnosed. The manufacturer was notified of the failure. The failure mileage was 29,000.

Complete engine failure while driving on a highway. While cruise was set, the truck emitted a sound and sensation like we had run over something on the highway. Within a few minutes the engine started ticking. The cruise was disengaged which thru the truck into neutral. No dashboard sensors were illuminated. We were able to get off the highway but the truck would not restart. Truck was towed to nearest dealer who has confirmed engine failure.

Complete engine failure. Safety is was put at risk one engine lost propulsion on a bridge with no median. Truck towed to a gm dealer that inspected it and replace the engine. Check engine light and low oil pressure light came on approximately 30 seconds before the engine died.

Engine knocking. Engine being replaced under warranty due to premature bearing failure. Picotest was performed prior to my purchase with 12800 miles. 0w40 oil being used at the time of failure. At the dealer now getting the engine replaced.

While traveling at highway speed during rush hour commute, the vehicle lost engine power and stalled. While coasting, I tried to restart the engine several times without success. Before coming to a stop, I attempted to get to the shoulder safely. Unfortunately, a portion of the vehicle was left partially in the lane and on the shoulder. Once I was completely stopped, I tried to put the electronic shift control into neutral so I could push the vehicle safely to the shoulder. The shifter would not allow me to shift into neutral and other override methods researched failed to work. I continued to try and restart the vehicle without success. I was in an unsafe position during rush hour commute for about 50 minutes until roadside assistance arrived and loaded and towed the vehicle. There was no warning of the issue prior to the incident. A code (p129f-fuel pump driver control module speed signal incorrect) was produced after the stall occurred via my GMC app. My vehicle was towed to my local dealership for service, but have not received the vehicle back at the time of reporting.

1. The l87 engine loss of propulsion failed and is available for inspection at the service department at power swain Chevrolet dealership, fayetteville, nc. 2. I, other vehicles, cyclists, and pedestrians were at risk. That vehicle could have come down on the highway, causing a vehicle pileup, which could have caused mass casualties. 3. The problem is known; the service advisor informed me the vehicle's engine needed to be replaced. 4. There were absolutely zero warning lamps or my GMC app alerts to announce vehicle issues. I have attached the last two maintenance records I have on hand. I suspect the dealership will try to deny responsibility for repairs. An extended warranty most nearly means we expect it to break down and your safety is not our concern.

Oct 2025 I took my truck into my local GMC dealer for 6. 2 recall. I was told it passed the testing. 6/12/26 driving about 70mph on highway and lost all acceleration. Warning stating engine oil hot,/ pull over and idle engine. Already using 0w40 oil for approx 8momnths. Oil changed approx 3 wks before this incident. I was able to pull to the shoulder w/in 1/4 mile. While the truck was still moving about 3 mph it went into park and shut off. The vehicle would not turn back on. Oil level was full. For about $300 I was able to have the truck towed to a local dealer (about 2hrs from my home) and have my trailer towed off the highway. 6/15/26 I was notified by a local dealer that the engine was seized and that this was probably the recall issue. I contacted my local dealer who had my truck towed to their location. On 6/19/26 I was told by local dealer rep that they had ordered an engine for my truck and that I was third in line. On 6/26/26 I was informed by the dealer that he engine is on an indefinite backorder nationwide. On 6/30/26 I received a call from gm giving me a case number and getting contact info for my local dealer. I was advised that someone would contact me within 48 business hours. 7/3/26 I was contacted by my case advisor from gm. Still no idea when replacement engines might be available. I inquired about a buyback since I need a truck for work/personal life. I advised her that I had already cancelled one vacation (towing an RV. . . My loaner Buick encore won't work) and would probably have to cancel another. I tried to explain that farming doesn't work well with the loaner either. I was told that another advisor would look into a buyback situation. On 7/8/26 I received a call from gm advising that my engine had shipped on 7/6/26 and to expect a call the following week with an update on completion.

The contact owns a 2023 GMC Sierra 1500. The contact stated that while operating the vehicle, there was an engine knock at start-up, and the engine intermittently hesitated and skipped. The vehicle was taken to the local dealer, who performed a pico test on the engine, and the engine passed. Later, while hauling a trailer, there was a rattling sound coming from the engine. The vehicle was taken back to the dealer, who diagnosed the vehicle and determined that the engine needed to be replaced. The engine, radiator, and oil cooler were replaced, and the vehicle was repaired. The manufacturer was notified of the failure. The failure mileage was 17,000.

Model: sierra denali ultimate engine: 6. 2l v8 VIN: [xxx] mileage at most recent incident: approximately 52,000 miles safety complaint summary I am submitting this complaint to report a recurring loss-of-propulsion and engine power event involving my 2023 GMC sierra denali ultimate equipped with the 6. 2l v8 engine. This vehicle has experienced two separate incidents in which it suddenly lost power while being operated at highway speeds. During both events, the vehicle unexpectedly lost propulsion without warning and without any apparent driver input or mechanical indication beforehand. No warning lights, check-engine lights, reduced-engine-power messages, service transmission messages, or other warning indicators were displayed prior to the failure. The vehicle simply lost power while traveling in traffic. During both occurrences, I was forced to safely maneuver the vehicle to the shoulder of the roadway while rapidly losing speed among surrounding traffic. Once stopped, the vehicle would not resume normal operation until it was restarted. After restarting, the vehicle appeared to operate normally; however, the fact that this condition has now occurred twice raises significant concerns regarding the reliability and safety of the vehicle. Safety risk this condition presents a significant and immediate safety risk because sudden loss of propulsion during highway operation can leave the driver unable to maintain speed, safely merge, maneuver, or avoid surrounding traffic. The unexpected reduction in speed creates the potential for rear-end collisions, loss of vehicle control, or other traffic accidents, particularly when operating on high-speed roadways. Because the vehicle provided no warning before losing power, there is little opportunity for a driver to take preventive action. Additional information • vehicle: 2023 GMC sierra denali ultimate • engine: 6. 2l v8 • VIN: [xxx] • approximate mileage: 52,000 miles • number of incident information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 55.

The lifters on my 2023 GMC sierra failed and damaged my engine. The truck has approx 78,000 miles. I do have an extended warranty to 100,000 miles. I got the truck to my GMC dealer who confirmed the problem was lifter failure. There might be camshaft damage but will have to tear the engine down. It seems like GMC is dragging there feet. It is known the lifters are a problem on this engine but GMC continues to sell them. There was no warning that the lifters would fail. The lifters could have failed while driving at high speeds and the driver could loss control.

I was driving my family on the highway and my truck completely shut down. The screen flashed a warning and it slowly started decelerating. Thankfully I was able to make it to the shoulder of the road safely. Engine failure was a known safety issue with my model of truck, but I completed the l87 engine loss of propulsion safety recall testing on 9/18/2025 and was assured my engine passed the testing and was not at risk for engine failure.

Truck starting bottom end knocking noise at 57,700 miles. Engine had the recall done to it for pico test and passed. Dealership states now it will need a new engine.

This vehicle has experienced repeated catastrophic engine and drivability failures since purchase and has now undergone four engine replacements under warranty. Despite these major repairs, the vehicle continues to experience dangerous shutdown/stalling conditions. The primary safety issue occurs while braking or coming to a stop. The engine will suddenly shut off unexpectedly, creating a serious traffic hazard and leaving the vehicle unable or difficult to restart. This has occurred multiple times and creates a dangerous situation in traffic and at intersections. The vehicle remains under manufacturer warranty, however the defect has not been successfully repaired despite extensive service attempts and multiple complete engine replacements. The condition substantially impairs the safety, reliability, and use of the vehicle. This vehicle was acquired through a fleet/lease arrangement for company use and was not purchased for resale. It is a light-duty 1500-series pickup with approximately 7,100–7,200 gvwr used as a company vehicle. Complete repair history, diagnostic records, warranty repairs, and engine replacement documentation can be obtained from: stevens GMC bristol, connecticut the vehicle has been repeatedly presented for repair and the defect remains unresolved. This appears to be a serious ongoing safety-related defect involving engine shutdown/stalling while braking or stopping.