2026 GMC Sierra EV 20-mod battery, 19kW 15-mode charger

Vehicle keeps displaying a warning message to service drivers assistance system. Taken the vehicle to the dealership multiple time and the condition still persists. Dealership contacts GM tech support and are being told that GM is aware of the problem, programing issue, but they have no solution after several months. Multiple vehicles at many dealerships have the same problem. I don't feel safe driving the vehicle. Drivers assistance system includes multiple cameras and sensors. This condition could cause severe accidents of even death if the system gives false or wrong information

ENGINE LOCK UP WITH 5018 MILES ON, IT IS A THE 6.2 MOTOR ROD AND CRANK BAD

Driving on the PA turnpike at speed with traffic and the engine lost power and started squealing. No lights came on, I was able to get to the side of the road and the truck shut off. When I restarted it, it sounded terrible. Had it towed to dealer and dealer stated that the engine had a terminal failure with the crank bearings and needs replaced. I was fortunate at the time of the issue that I was able to get off the road since the truck lost all power.

Complete engine failure at 1838 miles. Need complete engine replacement. Estimated time unknown for replacement parts.

Driving approximately 30mph, the engine shut down. Vehicle shifted into neutral until stopped and shifted to park. Unable to place in neutral to pull off the road. Check engine stated transmission needed service. Dealership states seized engine. Engines are on back order. Vehicle has 2980 miles on the odometer. I'm active duty Navy and have a permanent change of station this summer and no vehicle to move in and I also haven't gotten a rental.

The motor on my 2026 GMC Sierra stalled 2 weeks ago with a p0016(crankshaft position sensor issue). Was able to clear code and limp home. Vehicle did stall on a busy road and stop abruptly. Scheduled service and was advised to drive it in. Was experiencing irregular idle when warmed up, and a slight hesitation in the pedal. Service advisor started the vehicle and claimed no codes, and everything appear OK. Later in the afternoon the service advisor called to inform me that the vehicle had a siezed engine and had siezed during a test drive on the highway. Currently waiting on warranty information, and engine replacement information but i've been informed it will require a whole new engine. This is the same 6.2l L87 V8 that has been in near constant recalls from GMC over the last 6 years.

Engine Failure at 18,000. Knocking noise started immediately followed by vehicle going into low power mode. Dangerous to drive in traffic in low power mode. No other warning lamps or indications that something was wrong. Dealer inspected and found a bearing went out in the engine.

Radio has zero sound - the issue is the radio sound also has the blinker sound, hands free safety/navigation guidance along with the On Star safety function. None of that is functional. The dealer states it's a known issue and parts are not available. How can this be when they keep building new units. GM has been contacted with zero help and no response around my safety concerns. While it seems like a small thing when we say radio I'm not concerned with the lack of music but this system controls way more than music.

While driving on the highway my 2026 GMC Sierra 1500 Denali Ultimate the vehicle lost propulsion and the dashboard went dark because it shut off. I was exiting the highway onto a skybridge and rolled to a stop before reaching the top on the skybridge. Vehicle would not start again and needed to be towed. Dealership concluded my 6.2L V8 engine needed to be replaced due to crank shaft seizing. Engine had 1861 miles. This put me in a very dangerous situation due to the limited space on the skybridge with passing traffic.

MY 2026 GMC Sierra AT4 1500 6.2 L87 engine had a catastrophic failure with only 3347 miles. It stalled twice while driving home, when pulling into my driveway it stalled a third time and would not start after that. Before having my vehicle towed to the Dealer from my home I connected my code reader and it posted code P0016. After being diagnosed by the dealer they informed me I needed an entire new engine. There were no warning lights or message prior to this failure My vehicle was purchased 9 week prior.

I had this truck as brand new for approximately 24 hours when it had a major failure. It had 450 miles on it at time of purchase, but was sold as new. While driving at 45MPH it had a check engine light, service power steering message, lost power steering, lane departure system failure, and reduced power amongst several other lights on the dash. I limped the truck into a gas station parking lot. After turning the truck off, it would not restart. I unhooked the battery for a minute and hooked it back up. The truck did restart with no messages or check engine light. I was able to safely get it to the dealership. As a result of this issue, I forced the dealership to cancel the trade.

I am the owner of a 2026 GMC Sierra 1500 Denali Ultimate equipped with the 6.2L V8 L87 engine (VIN: [XXX] ), purchased new approximately three months ago. I am filing this complaint proactively. I have experienced no engine failure or symptoms to date. However, I am filing based on a documented pattern of L87 engine failures in 2025 and 2026 production vehicles, confirmed by multiple GM dealership technicians, which suggests that the manufacturing defect underlying NHTSA Recall 25V-274 may not have been fully resolved by GM’s stated production improvements dated June 1, 2024. NHTSA Recall 25V-274 (April 2025) covered 597,630 vehicles from model years 2021–2024 for catastrophic L87 engine seizure caused by connecting rod bearing failure and crankshaft defects. GM excluded 2025 and 2026 model year vehicles based on a claimed manufacturing fix. However, multiple 2026 production vehicles have since experienced the same bearing failure at extremely low mileage. Open NHTSA Investigation EA25007 is already examining vehicles outside the original recall window, and Recall Query RQ26001 is investigating the adequacy of GM’s remedy. I am requesting that NHTSA consider expanding the investigation scope to include 2025 and 2026 model year vehicles. As a 2026 owner of a $90,000+ truck with the identical engine configuration, I believe my vehicle warrants inclusion in any expanded investigation or recall action. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My engine seized up on me on the highway. I was stranded and couldn’t start the vehicle and it was freezing outside.

I was out of town and driving on the highway around 75 MPH, when the motor suddenly lost all power. I was driving in the far left lane approaching an overpass. The sudden loss made it next to impossible to make it off the overpass on a very busy freeway safely while trying to navigate many cars trying to pass me. The truck came to a complete halt on the white shoulder line, 50' off of overpass SH 31. The truck would not restart or do anything i could not push it any further off road. I excited the e truck and stood off the freeway for my safety, as the truck was on very edge of freeway. GMC Roadside assistance took my truck to nearest dealer. This occurred on a Friday, dealership gave me a loaner car to get home as i was from out of town. They stated it would probably be the following Tuesday maybe Wednesday before they could tell me anything. I never heard from dealership service department, so i called them on Thursday morning and was told my truck motor had seized up and a new motor was needed. Service advisor stated GMC had been contacted and paper work started and I would be getting a new motor. The service advisor also stated that he had called and left a message. We verified my phone number and he had correct number, however I still never receive a call or voice mail. I still have not received any documentation on the failure or a repairs needed.

"Vehicle is experiencing symptoms consistent with the 6.2L L87 engine bearing failure investigation (NHTSA Probe January 2026). Despite two repair attempts, the dealer claims 'operating as designed.' I have experienced persistent engine stumble,hesitation, erratic tachometer needle flutter and significant vibrations felt through the floorboard and seats during operation. These defects substantially impair the use,value and safety of my vehicle.This is a serious safety concern as it creates a risk of catastrophic engine seizure at highway speeds. Manufacturer has been sent a formal 'Last Chance' letter under NJ Lemon Law." Reference # 1771884

Vehicle stalled in busy intersection in McKinney Texas, unable to start are shift into a neutral position on transmission to remove from extreme dangerous intersection, sheriff advised that road side assistance that was contacted is not going to be in time (90min)to keep from causing an ongoing traffic backup, sheriff dispatched their own towing service to resolve the situation from getting extremely dangerous.vehicle and my wife was towed to McKinney Buick gmc dealership.

Odd noise from bell housing area at 1200 miles that went with engine rpm. Took the truck in to the dealer and they said they couldn't recreate it but to bring it back in if it returned. Jan 27th at 5200 miles on the truck, I was driving down the highway at 60mph and got a reduced acceleration message on the dash along with a check engine light. Brought it to the dealer and was informed it was a bad thrust bearing and needed and engine and turbo replacement. Still waiting for the truck to be done.

My 2026 GMC AT4 3.0L Duramax had a catastrophic engine failure on Sunday, February 8, 2026. It went into reduced acceleration and also fault code PO6DD. Thankfully I was not on a highway. The truck would not run over 45 MPH on flat ground, and then by the time I got it to a safe location 5 miles away it would not run over about 30MPH. This obviously resulted in the truck being towed to a dealership. I have been told the entire engine will be replaced. Upon further reading, I suspect this is a thrust bearing failure that is a well-known issue in this LZ0 Duramax engine. What I have read, this issue is occurring mostly on trucks built from May-Sept 2025, and my truck has a 7/2025 build date. This could have been major safety hazard if the engine had failed in a major freeway/highway.

I am submitting this complaint regarding a recurring transmission issue in my vehicle. The transmission consistently jerks and shifts erratically, particularly in the morning during initial operation when at cruising speeds of about 50-75 mph. This behavior occurs when the transmission temperature is below approximately 100°F and happens on a daily basis. The gear changes feel harsh and abrupt, kind of like it doesn’t know what gear to be in its raising concerns about both drivability and long-term transmission reliability. I brought the vehicle to an authorized dealership for inspection. After evaluating the issue, the dealer informed me that the behavior was due to the vehicle being in “Sport Mode.” However, this explanation does not resolve the concern, as the severity and consistency of the jerking appear abnormal and occur regularly under the same temperature conditions. Given the persistent nature of this problem and its potential safety implications — especially during acceleration and low-speed driving — I am requesting that this issue be formally documented and investigated. Thank you for your attention to this matter.

The contact owns a 2026 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle made an abnormal sound and failed to accelerate as needed. There was no warning light illuminated. The vehicle was taken to the dealer, who determined that the engine needed to be replaced. The vehicle was not repaired and remained with the dealer. The manufacturer was not made aware of the failure. The failure mileage was approximately 6,000.

"Vehicle exhibits a severe RPM flutter and rhythmic harmonic vibration at idle. These symptoms are consistent with manufacturing defects in the connecting rod and crankshaft currently under NHTSA RQ26001 and EA25-007 investigations for the GM 6.2L L87 engine. The defect presents a substantial risk of sudden engine seizure and loss of propulsion while driving. Vehicle is currently out of service at Jim Curley GMC for its first repair attempt. The dealer has stated repairs will not begin for several days."

Total engine failure at highway speed with loss of propulsion. Catastrophic engine loss with 3,000 miles. GMC never fixed the problem with the 6.2 l87 like they said

I heard a loud metallic knock that was not consistent with normal engine noise. I noticed the oil pressure was on the lower end of the scale but not abnormal based on how it is displayed. I decided to take the vehicle to the dealer ASAP for an oil change (that was coming due) and discuss with them. I drove roughly 20 miles from start of noise until delivery at the dealer. The truck gave me a "Reduced Acceleration, drive with caution" message 10 miles prior to the dealership but no associated lights, engine codes, check engine light or associated alerts on the myGMC app. Dealership found oil pressure ranging between 4-8 psi, and a failed oil pressure control solenoid, heavy metal debris in the oil pan including parts of the thrust bearing and oil squirter. Entire engine and turbo replacement was required. Truck had 143 hours on the engine and 6,300 miles. It was produced in August of 2025 with a purchase date of 17 October 2025. Produced: 8/25 Purchased: 10/17/25 Failed: 12/30/2025 Returned with new Engine: 1/23/26

GMC SUPER CRUISE MALFUNCTION NO WARNING BEFORE SUPERCRUISE SHUTS OFF PASSING A CAR ON FOUR LANE HIGHWAY (SUPER CRUISE ENABLED) SUPER CRUISE SHUT OFF AND TRUCK CONTINUED HEADING FOR THE CENTER GAURD RAIL.(I CAUGHT IT BEFORE IT BECAME AN INCIDENT). SUPER CRUISE ABRUPTLY SHUTS OFF (NO WARNING) AND WITHIN A COUPLE THOUSAND FEET IT TURNS ON. MY FIRST TIME USING SUPERCRUISE AZ HIGHWAY 87 N BOUND JUST BEFORE RYE AND AZ HIGHWAY 260 BETWEEN PAYSON AND CHRISTOPHER CREEK I CALLED MY DEALERSHIP BUT IT WAS LIKE UH HUH OK I'LL LET GM KNOW.- NO SUPPORT! THE ONLY INDICATOR IS ON THE STEERING WHEEL A RED,GREEN OR YELLOW LIGHT.RED IS OFF-GREEN IS ACTIVE, AND YELLOW LIGHT NO SERVICE. RED LIGHT COMES ON AND SEAT VIBRATES SUPERCRUISE DROPS OUT.

2026 GMC Sierra Elevation X31 with 3.0 Duramax Diesel engine, 132-miles, thrust bearing 1.53-mm out of tolerance requiring engine and turbo replacement. Engine build date 25219 (07 AUG 2025), vehicle assembly date August 2025, purchased 10 OCT 2025, entered service for engine and turbo failure on 11 NOV 2025, returned 10 JAN 2026.

26’ GMC Sierra 1500 AT4 3.0l Duramax experiencing Harsh shifting occurring sporadically while accelerating and deceleration. More frequent and severe during quick deceleration. Severe clunking/rear wheel lock up while reversing. Very repeatable. Truck was a dealer demo and had 2400 miles on it when I bought it last week. Took it in to the dealer today and they said I need a complete new transmission.

2026 Sierra 1500 AT4 with 3.0L Duramax Diesel. Three major issues. 1. 2960 miles, thrust bearing failure caused low oil pressure and internal damage. Vehicle needs complete engine replacement. The truck is still at the dealer with no ETA on engine arrival and replacement. 2. Vehicle has severe electrical issues. battery replaced on second day of ownership due to over charge and smoking. The truck would randomly lose the ability to produce sound through infotainment system on start. This includes warning sounds and audible turn signal sound. Dealer said it’s caused by faulty Amp which was replaced. 3. The truck shut off (full system shutdown) and the transmission failed over to neutral while driving on the highway and failed to restart. Barely restarted on second attempt. Dealer has no idea why it is doing it. However the vehicle was throwing multiple code related to transmission module failure, brake module failure, transmission module failure, etc.

3.0 Duramax Engine Failure - 2026 GMC Sierra 1500 Denali Ultimate at just 6,755 miles and only 77 days of ownership. Within the first few thousand miles, the truck intermittently had warnings appear of “reduced acceleration, drive with care”. The truck would limit its ability to maintain speed. When it occurred during highway driving, it was particularly dangerous. The check engine light would also come on. After parking the vehicle for a bit and restarting it, things returned to normal. At the dealership, we reported the issue and leaned the computer reveled a P06DD code which required them to check the crankshaft for excessive play. Our truck was out of specification requiring complete engine replacement at just 6,755 miles. “Service Bulletin 25-NA-307 which states this code may set due to thrust bearing failure. following 25-NA-307 checked crankshaft end play and got a reading of 0.3400 in. the maximum spec is 0.0124 in.“ GM and Laura Buick GMC should not have sold this truck to us without inspecting it for this known issue. This extensive repair required complete removal of the cab from the chassis.

My 2026 GMC 1500 is equipped with the 2.7L L3B & 8L90 Transmission. At approximately 1000 miles, I noticed that in 2nd between 2700-3200 RPM, a vibration could be felt throughout the cabin and would occur whether with or without throttle application. I am able to recreate the issue during hard acceleration or placing in manual mode. No matter the Vehicle mode selection (sport, normal, snow, tow/haul, etc.), the issue still persists. I took the vehicle to a local GMC dealer at approximately 6K miles to diagnose. I requested that we test drive another 1500 with the same 2.7L and Transmission. They brought out a 2026 Elevation Quad Cab with the 2.7L; less than 20 miles on the odometer.The same vibration was present in 2nd gear at same RPM band. I requested that the issue be escalated to a local GM rep. for further investigation. However the response from the dealer was inadequate and basically stated that no warranty work would be considered because it seems to be “normal operation”.

The contact owns a 2026 GMC Sierra 1500. The contact stated that upon starting the vehicle and shifting into reverse(R), the vehicle failed to move while depressing the accelerator pedal. The contact felt a hesitation while depressing the brake and accelerator pedals, and the contact then attempted to restart the vehicle. The contact restarted the vehicl;e however, while attempting to accelerate, the brakes independently activated. Despite the repeated failure, the contact was able to pull into a gas station to restart the vehicle. The contact stated that after several attempts, the vehicle finally resumed normal operation, and the contact drove the vehicle to the residence. The next day, the contact test drove the vehicle, and the failure reoccurred while the contact was attempting to park the vehicle in a parking spot. The vehicle was taken to a dealer, where a diagnostic test produced 7 fault codes; however, the mechanic was unable to repair the vehicle. The manufacturer was notified of the failure, and the manufacturer stated that there was a communication disconnect between the contact and the dealer. A case was filed with the manufacturer. The vehicle was not repaired. The failure mileage was approximately 300.

I do not have an official communication from the dealer who is servicing my vehicle. However, they have had my vehicle for almost 3 weeks and they tell me that the engine has failed and needs complete replacement. They said the engine lost compression and quit running, it now cranks and does not start. Although the engine has not been disassembled we believe the point fo failure to be in the rotating assembly of the bottom end of the engine.