2023 GMC Sierra 1500 Engine Problems

Code P1098 came up today 80k on the truck. Coolant Control Valve failure. Second time this has failed, first at 45k. Speed reduction activated.

NHTSA ID

11766541

Incident

Sep 22, 2026

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.

NHTSA ID

11766203

Incident

Sep 19, 2026

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.

NHTSA ID

11765460

Incident

Sep 16, 2026

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.

NHTSA ID

11764633

Incident

Sep 10, 2026

A GM warranty engine replacement was performed at Heyward Allen GMC in [XXX] on XXX at 70,415 miles. We purchase the vehicle on XXX with 73,904 miles and after driving for a month started having multiple malfunction indicator lights displaying, and experienced a no start condition. We took the vehicle to the Don Ledford GMC dealer in [XXX], and they performed a high level inspection. They found missing mounting brackets, loose wiring harness wires, broken and missing bolts. Issues all related to an engine replacement procedure. Deeming the vehicle unsafe to operate. The origin dealer that was paid through GMC to replace the engine is now refusing any responsibility for resolving these issues. Technicians have video evidence of the workmanship issues, documenting the sub- par repair work performed during the engine change. The vehicle now sits at the Don Ledford GMC dealer awaiting an estimated $4400 repair, before the vehicle is safe to operate on the road. The vehicle has been at the Don ledford dealer since XXX, and is still there today, XXX. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11763072

Incident

Feb 23, 2026

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.

NHTSA ID

11763017

Incident

Sep 7, 2026

Mileage

12,998 mi

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.

NHTSA ID

11762905

Incident

Aug 7, 2026

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)

NHTSA ID

11761755

Incident

Sep 2, 2026

I am reaching out to NHTSA due to a vehicle that I believe will get me and/or my family in a major accident and cause serious injury or death. The vehicle that I had purchased in 07/08/2025 had a clean history report and was bought at 54,587 miles. It started having issues 8,563 miles later (odometer reading 63,150 ) on a trip that was 400 miles round trip. I was driving the vehicle on a highway at 65 mph and i felt a knocking vibration in the pedal it was not long before i could even pull over when the engine throttle had completely lost power causing the vehicle to almost come to a complete stop immediately having to steer onto the shoulder. after failing with no check engine light or warning present during the use of the vehicle on the road. it was giving off high temp/engine overheating with the engine making a continuous knocking sound in the engine. It eventually seized to work completely not being able to shift into neutral to push, and had to get it towed to the dealership 204 miles away. GM had advised the dealership to replace the whole engine which they did, and that second engine had given out 678 miles later (odometer reading 63,828.) I am now on my THIRD engine and i cannot trust or rely this vehicle for saftey or transporation. i have reached out to GM to file a claim and attempt to adress this issue to try and come to a resolution, however they denied my claim and have said that i am not "eligible" for a buyback program. I am considering getting legal attorney this is very frustrating to say the least GM is a terrible manufacturer for this issue

NHTSA ID

11761466

Incident

Mar 29, 2026

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.

NHTSA ID

11761354

Incident

Jul 9, 2026

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.

NHTSA ID

11760817

Incident

Aug 26, 2026

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.

NHTSA ID

11760713

Incident

Aug 22, 2026

1 - The Engine or something electrical, possibly the ECM, failed or malfunctioned, and yes, it is available for inspection. 2 - The vehicle lost power, reduced speed, was hard to steer, and I couldn't put the hazard lights on; this occurred twice while driving on the highway, once I was driving at approx 75 mph. The results could have been catastrophic not only to myself but to others on the road. These two events are not the only times the truck did this. 3 - No. 4 - No. I filed a claim with GM, but it has been approximately a month, and I've received no updates. 5 - No. Further: This event has occurred 6 times. I've taken it to the dealership three. They cannot duplicate the issue, so no repairs have been done. Apparently, approximately 100 codes come up, but they cannot diagnose the problem.

NHTSA ID

11760654

Incident

Feb 28, 2026

I am a Canadian owner of a 2023 GMC Sierra 1500 AT4 equipped with the 6.2L L87 engine. VIN: [XXX]. I purchased the vehicle new. I am reporting this because my experience appears directly relevant to NHTSA Engineering Analysis EA26005 concerning L87 engine failures after Recall 25V-274 remedies. The GM recall remedy/oil change was performed at 103,503 km (64,315 mi). At 130,695 km (81,210 mi), the original engine suffered a catastrophic failure and completely seized. The engine could not even be rotated manually at the crankshaft. GM replaced the complete engine. At 142,541 km (88,571 mi), only 11,846 km (7,361 mi) later, I returned for the first oil change on the replacement engine. I told the dealer that the vehicle was behaving abnormally, especially the transmission, which was shifting strangely. After inspection, the dealer determined that the replacement engine was beginning to seize. The increased resistance from the engine was causing the abnormal transmission behavior. The complete engine was replaced AGAIN. The vehicle now has 148,560 km (92,310 mi), meaning this second replacement/third engine has only about 6,019 km (3,740 mi). I am again noticing symptoms similar to those that occurred before the previous engine failure. I cannot confirm that this engine will fail, but after two previous engine failures, I am very concerned. This vehicle has therefore had two L87 engines: the original engine and one replacement. One replacement engine itself began seizing after less than 12,000 km. I believe these repeated failures after both the recall remedy and a complete engine replacement are directly relevant to EA26005 and the safety risk of sudden loss of propulsion. I have GM/dealer repair orders documenting the recall service and both engine replacements and can provide them upon request. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11760512

Incident

Mar 16, 2026

Truck went into limo mode while driving and required valve in transmission to be replaced. Went from driving normal speed to only being able to go about 15 miles and hour. Was repaired got the truck back and the next day was on the interstate in the fast lane and the truck again had speed issue reduced speed and had to coast off interstate. This time entire valve body had to be replaced. Have gotten truck back and still have hard shifting in the transmission at times. Engine was checked for recall and now I have to pay a much higher oil change price due to a GM issue. This was not a known cost when purchasing this truck.

NHTSA ID

11760485

Incident

Mar 27, 2026

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.

NHTSA ID

11760415

Incident

Aug 5, 2026

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.

NHTSA ID

11759610

Incident

Jul 2, 2026

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.

NHTSA ID

11759491

Incident

Aug 14, 2026

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.

NHTSA ID

11759333

Incident

Jul 6, 2026

Mileage

29,000 mi

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)

NHTSA ID

11758888

Incident

Jul 30, 2026

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.

NHTSA ID

11758867

Incident

Aug 23, 2026

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.

NHTSA ID

11758858

Incident

Aug 23, 2026

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.

NHTSA ID

11758664

Incident

Jul 17, 2026

- vehicle started misfiring, ECM, valve timing code, throttle system code, data system, gateway, module,. Vehicle is available and currently at the GMC dealership for continued diagnostic. -this happened on the freeway and out of nowhere the vehicle started shaking, rough, losing power and acceleration, I had to cut someone off on the freeway just to get over to the right shoulder and turned off the vehicle called a tow truck and haven’t been able to use the vehicle since. Vehicle is unable to be driven due to safety issues of increased acceleration and loss of power, intense shaking. -the vehicle is at the dealership now, prior there was a diagnostic performed by a different dealer, and it has been confirmed. -the vehicle is at the GMC dealership now. -ECM check engine light came on prior to the vehicle misfiring and other codes coming up.

NHTSA ID

11755389

Incident

Feb 3, 2026

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.

NHTSA ID

11752365

Incident

Jul 4, 2026