2024 GMC Sierra 1500 Powertrain (other) Problems

My truck has experienced recurring diagnostic trouble code P244B on [XXX], [XXX], and [XXX], 2026. The latest occurrence included a check-engine warning and reduced engine power. On [XXX], at 40,833 miles, Neil Huffman Chevrolet GMC in Frankfort, Kentucky, diagnosed a damaged diesel particulate filter differential-pressure sensor connector. The dealership's written estimate states that the connector had shorted, begun melting, and had broken wires at the back of the connector. I am concerned about the cause of the electrical overheating, the possibility of additional wiring damage, and the risk of unexpected reduced engine power while driving. I have also experienced intermittent transmission-related warnings and communication fault codes, although I do not know whether these problems are related. I understand there are GM technical bulletins addressing wiring-harness damage on certain 3.0L Duramax vehicles. I am not claiming these bulletins establish the cause of my failure, but I would appreciate having my experience evaluated for a possible safety-related defect trend. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11773640

Incident

Oct 20, 2026

Driving at approximately 45 mph on Berthod Pass in CO, towing a snowmobile flatbed trailer, when dash display indicated "low oil pressure, Turn off Engine". By the time I could read that, the engine was already off and I was all over the road trying to find a way to get off the highway. I did not have opportunity to get off highway, and ended up against a barrier, and partially remaining in traffic. GM towed the car (not the trailer, I had to do that myself) to a dealer quite some distance from my home as opposed to the dealer where I purchased the truck. Then they told me they towed it to a different dealer. After recovering my stuff, I went to the dealer where the truck was, and they said they couldn't look at it for several days. I could not wait several days simply to find out it was going to be a couple of months before id have the truck back. I traded it in on another, larger GMC simply to get out of that engine. What I learned though, is that GM used that exchange to make about $20K. This was more the dealer, but they are part of GM. My original truck was priced below book, and not the book the public can see, but the book they say they go by. They paid me $51K on an $87K truck for trade value. Then they sold the new truck at full price, no break. I was in disaster mode, as I had a large family gathering I was preparing for at our cabin, and did not have time to fight with them. The reason for the low book trade-in value was that the value of these trucks has plummeted because of the very reasons I was replacing it, GM's failure on those engines. My original truck had about 30K miles on it when it blew. The dealer told me that the one I was replacing it with (2026 Sierra HD with 6.6L Turbo Diesel) would get similar mileage, but that was untrue. I get about half the mileage I got in the first truck, and the price of diesel is about 20% more than gas. So they found a sucker on the first truck, then that same sucker bought the second one.

NHTSA ID

11769455

Incident

Aug 28, 2026

At approximately 2 years, 47,000 miles I received a message that I needed to service the transmission soon. I then got a message "Trailer Brakes Disabled Service Required" and another "Service Transmission Now Unable to Shift Soon". I brought the vehicle into my closest GM dealer and they said it is a faulty shift control lever. These are known to have a fault from the factory, but since I am outside of the 36,000 bumper to bumper, they will not cover the cost. It took about 2 months for the part to come in as it was on back order, and now they want $1000 to replace it.

NHTSA ID

11768050

Incident

Jul 20, 2026

The contact owns a 2024 GMC Sierra 1500. The contact stated that while driving 55 MPH, the message "Reduced Acceleration" was displayed and the vehicle decelerated quickly, and the contact was forced to pull over to the side of the road. The vehicle was taken to the dealer on several occasions to be diagnosed. During the first visit, the dealer stated that a transmission error code was retrieved and was cleared before the vehicle was returned. During the second visit, the dealer stated that the engine was consuming an excessive amount of engine oil and recommended that the engine be replaced. The contact stated that the message "Reduce Acceleration - Drive with Care" was displayed, and the vehicle went into LIMP Mode. Occasionally, after shifting to drive(D), the engine revved but the vehicle failed to respond, and the vehicle was taken back to the dealer. The manufacturer was notified of the failure. The failure mileage was 74,200.

NHTSA ID

11767880

Incident

Apr 1, 2026

Mileage

74,200 mi

I purchased a 2024 GMC Sierra 1500 Denali VIN # [XXX] on XXX with approximately 18,599 miles on the vehicle. The incidents are identified below in order. 1) XXX, Vehicle engine failure while driving at high speeds, with my daughter as a witness. I Reported the incident to Elder Ford on XXX, and my sales associate told me to take it to GMC for factory warranty. XXX took the vehicle to Central Buick GMC they performed a test that found no codes and replaced the fuel Pump Module from past experiences. They let me take the vehicle home. 2) XXX Vehicle engine failure while driving at high speeds, had to get it towed to the dealer for repair. Again, they found no codes. Had it for 5 days. Made me take it home. 3) Picked it up on XXX , was driving home and the same thing happened while going 70+ mph on the interstate. Stalled again. Drove it back to the dealer and dropped it off again, same day on the XXX. 4) Again, they found no codes and made me pick it up on XXX I was driving home on XXX and the same thing happened- lost complete power while going down the road at 40+ MPH. I had to get it towed the same day back to the dealer where it currently is at. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11767218

Incident

Aug 31, 2026

Lifters and camshaft failure, loud clanking, & sudden power loss on the 6.2 motor are the first noticeable signs. Instantly when everything happened check engine light, cruise control, & stabilizer lights flashed. The sudden loss of power forced the vehicle to suddenly slow down forcing my camper into the truck. I was hauling a within weight standerd camper but had difficulty bringing both the truck with the camper to a safe stop. There were no early signs or signal prior to sudden cautostrophic engine failure & all service records have been completed by a GM certified service dealer.

NHTSA ID

11763115

Incident

Sep 3, 2026

I was driving north/east on [XXX] just outside of [XXX]. After accelerating to give another driver room to move out of his lane that was ending, I lost propulsion/power. The Sierra went into Neutral and told me something like "Press Start to resume". I had to immediately get off the interstate as I was rapidly losing speed. I was able to pull over to the shoulder of the interstate on the right, just before exit 2. After getting the vehicle parked, I was never able to restart the vehicle. The motor would not turn over. The display screens kept cycling between a blank display and a display that looked like the vehicle was on but the engine never turned on. When I tried to start the car, I got a message of "conditions not correct for shift". We could not even get the vehicle into Neutral. I used OnStar to get State Patrol to show up and put lights behind us for safety. OnStar should have a recording of this call. This was on Saturday XXX in the ballpark of 2:30 pm central time. I would imagine the officer also filed a report, but I did not get it. The vehicle was towed to Billion GMC in Iowa City. Billion GMC said their initial suspicion is the 6.2L motor failed / locked up on us as this is know issue that is subject of a class action lawsuit. These vehicles ARE NOT SAFE to be on the highway, someone is going to get seriously injured, please do everything you can to get these 6.2L engines off the road before someone dies. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11757264

Incident

Aug 15, 2026

transmission shift hard and slipping. When step on gas to go faster transmission shifts really hard like going drop on ground. Sometimes wont shift at all only goes up to 69 till left off gas and then transmission will shift. Start happening with about 10000 miles on truck and GMC said this is normal. Now need a torque converter and shift module in it.

NHTSA ID

11756150

Incident

Jul 17, 2024

Was traveling home and started losing power going up a hill on XXX. The truck was surging, the check engine light came on and an audible warning of no (low?) oil pressure. The truck shut off on a busy interstate highway and barely got onto the shoulder. The tow truck driver had to lay on the ground with part of his body in the lane of travel to place "skids" under the rear tires because there is no way to place this vehicle in neutral for a tow without a special GM tool. When I contacted Harry Robinson GMC service center in [XXX], they told me that it was no longer a safety recall because the truck had passed diagnostics and new, high viscosity oil was put in the truck XXX. The GMC app says code P0016 which is the dreaded 6.2L camshaft to crankshaft alignment that accompanies engine component failure. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11755885

Incident

Aug 9, 2026

Ever since I bought this truck new, I noticed a lot of metal shavings and debris in the oil filter every single time I changed the oil. I took it to the dealership multiple times to have this looked into before the engine recall came out. The dealership took pictures of the metal and sent them to a General Motors engineer, but the engineer just told them it was "normal." Later on, the truck went in for the official recall inspection, passed the PICO test, and nothing was fixed. Then on August 4, 2026, I was driving on a crowded expressway right through a construction zone with absolutely no shoulder to pull over on. Out of nowhere, the truck started hesitating badly, lost power, and the engine started making a really loud knocking noise. It was barely running, and it was incredibly dangerous because there was nowhere to go and traffic was heavy. Luckily, I was able to limp the truck along just far enough to clear the construction zone and pull over safely.

NHTSA ID

11755085

Incident

Aug 4, 2026

While driving on XXX I received a message on the dash: service transmission, will not be able to shift soon. I went to the nearest GMC service center, located in [XXX]. Their diagnostics indicated that the Gear Shift Control Module needed to be replaced with new PN 86421783. That part was not available until XXX, but old PN 86274946 was available at a few dealersships, and it acould possibly be ordered and arrive sooner than XXX. I was told that driving the truck would be okay, but the part should be replaced as soon as possible. I live over an hour's drive from [XXX], and with the assurance that driving the GMC was okay, I chose to have the part shipped to and replaced at the dealership in [XXX], the nearest one to [XXX]. I drove back to [XXX], stopping at the Waldoboro dealership to make an appointment for their inspection of my truck, their troubleshooting the problem, and ordering the necessary parts to repair the transmission. When the part number went into their ordering system, the dealership was advised that no parts were available and no availability date was known. I contacted GMC Customer Assistance to express my concern and request assistance in locating the parts, but she was also unable to locate the parts or speed their availability. Again, on the assurance that the truck was okay to drive, on XXX I drove to my storage units near [XXX], and when I tried to leave and shifted into reverse the truck would not move. AAA towed me to the dealership in Waldoboro, and the replacement parts search began. Finally, on 7/28/26 I was advised that the part was at the dealership, and on XXX I picked up my repaired GMC truck. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11754176

Incident

Jul 15, 2026

I was driving on the highway when the vehicle started to make clinking noises. The vehicle started to lose power as I accelerated it would feel like something was pulling me in the opposite direction and the knocking noise would get louder. Ultimately, I had the vehicle towed to a dealership. This vehicle passed the L87 recall not too long ago, and the vehicle is barely used.

NHTSA ID

11752276

Incident

Jul 22, 2026

The vehicle suffers from a persistent transmission defect including shuttering bucking slipping torque converter failure valve body failure twice metal debris improper down shifting chirping noises and related liability and safety issues. The vehicle has undergone multiple unsuccessful repair attempts at authorise GM dealerships. These repairs include torque converter replacement valve body replacement twice solenoid replacement fluid services software updates. The transmission problems have persisted despite these efforts and the vehicle has been out of service for more than 22 business days including a breakdown driving to Florida. I have filed a claim through GM but it seems like it just keeps getting pushed further and further away this is a serious safety issue as I fear for those driving around me and myself that I may cause an accident with the bucking slipping and failure to operate properly on the road.

NHTSA ID

11748050

Incident

Feb 10, 2026

Issue is with the transmission as it harshly shifts into a low gear when on an incline. This causes me to lock up my breaks as it feels like the truck was rear ended by another vehicle. I’m concerned that this is going to cause an accident. This problem has not been reproduced by the dealer. I’ve taken it to the dealership several times. No warning lamps or messages.

NHTSA ID

11744152

Incident

May 28, 2026

My truck engine has failed due to metal shavings in the oil related to the L87 engine recall, and the failure occurred after GM had replaced the truck’s oil as part of the recall remedy. The recall remedy did not prevent the failure of the engine.

NHTSA ID

11743967

Incident

May 28, 2026

My truck engine has failed due to metal shavings in the oil related to the L87 engine recall, and the failure occurred after GM had replaced the truck’s oil as part of the recall remedy. The recall remedy did not prevent the failure of the engine.

NHTSA ID

11743965

Incident

May 28, 2026

I was driving down the highway when all of a sudden felt a hesitation and then seen message low oil pressure turn off vehicle and was just able to pull of the exit ramp of the highway when the truck had complete loss of power and then Died..called dealer right away and was flat bedded to the dealer..This just happened yesterday (06/08/26)

NHTSA ID

11742868

Incident

Jun 8, 2026

The vehicle received the official N252494001 recall oil remedy on 06/27/2025 at 15,438 miles (but suffered catastrophic engine failure and loss of propulsion at 33,661 miles on 05/30/2026).

NHTSA ID

11741282

Incident

May 30, 2026

Check engine light illuminated with service transmission. The next day transmission started slipping and finally would not engage in reverse. Dealership Has it now and after diagnosis they advised that they had replaced the electronic control module to which, on the test drive, the gauge cluster blacked out and they got more codes. The cpdes that the vehical threw were the transmission valve body needed to be replaced.The truck has 24k miles on it.

NHTSA ID

11739083

Incident

May 17, 2026

Burnt engine oil, breakdown of viscosity, low oil warning light prior to required change, and oil consumption. Multiple events and oil changes with same results of oil fluid conditions and consumptions with low-mileage engine and overall vehicle.

NHTSA ID

11735643

Incident

Nov 6, 2025

The contact owns a . The contact stated that upon restarted the vehcile experienced harsh restarts and lurch forward. The contact indicated that the failure and become more frequent. The vehicle was taken to the local dealer was unable to duplicate the failure and no service was performed. The manufacturer was notified of the failure.. The failure mileage was 33,400.

NHTSA ID

11735449

Incident

Sep 1, 2025

Mileage

33,400 mi

Engine seized

NHTSA ID

11732188

Incident

Mar 19, 2026

When I begin to accelerate on the highway, and the truck downshifts, it locks up the rear brakes.

NHTSA ID

11730614

Incident

Apr 11, 2026

While driving west on Hwy 20, near Augusta, GA my vehicle motor blew without any warning. I had to guide my dead but rolling truck and trailer to the side of the Hwy against a high retaining wall. The truck shut down and set the brakes after stopping and would not restart, shift into neutral, or move without special two equipment. **when I received the first recall notice I call my GMC dealer and they said their was nothing they could do yet. Later I received a second notice and responded to GMC dealer where the changed the oil and cap. A few weeks/months after that the motor blew. GM has refused to be any help and replacement motor has been on back order for 3 weeks and counting.

NHTSA ID

11729098

Incident

Mar 12, 2026

While driving a "Service Transmission" message appears on the information center. The truck shifts slowly, sometimes slamming into gear, doesn't seem to have smooth acceleration through the gears until a high gear is reached. Unusual sounds occur during the shifting sequence. The vehicle was dropped off at the dealer for service. Dealer claims that since they were not able to duplicate the conditions reported to them, the vehicle was fine and not in need of any further investigation or service. Transmission problems are a known concern with vehicle as recalls have been expanded to include this class of truck in the recall but GM is not including this vehicle.

NHTSA ID

11727368

Incident

Mar 25, 2026