2025 GMC Sierra 1500 Engine Problems

The contact owns a 2025 GMC Sierra 1500. The contact stated that while driving approximately 5 - 10 MPH, the vehicle went into LIMP Mode and failed to properly accelerate, and the transmission unexpectedly downshifted. There was an electrical malfunction, which caused the transmission to downshift. An unknown message was displayed on the instrument panel. The contact stated that the network was not operating at the correct voltage due to the wiring harness. The engine light illuminated after the failure. The vehicle was towed on two occasions to the dealer to attempt to duplicate the failure. The dealer was unable to determine how to repair the vehicle. The vehicle was driven to the dealer in LIMP Mode. The manufacturer, General Motors, was contacted by the dealer, and the contact also reported the failure to the manufacturer. A General Motors service engineer had inspected the vehicle. The failure mileage was approximately 34,637.

NHTSA ID

11765016

Incident

Sep 2, 2025

Mileage

34,637 mi

When updating the vehicle as prompted by the entrainment system the next day when attempting to start the vehicle it did not start. Vehicle had to be jumped then 6 warning lights came on and disappeared shortly after driving.

NHTSA ID

11763207

Incident

Sep 9, 2026

On XXX my 2025 gmc sierra 6.2L v8 engine experience catastrophic engine failure with no preexisting alerts or warnings. It was towed to Baglier gmc in [XXX] on XXX and is currently awaiting diagnostic evaluation. Upon restarting the vehicle after failure, the engine light did turn on. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11762694

Incident

Sep 5, 2026

So I spent many months trying to aquire a GMC Sierra Denali and with all the issues with the 20 - 24 6.2 engines we were assured by the dealer that all the issues were resolved with the 2025 6.2 models. So we spent big to aquire an 2025. So I bought one new. My truck had 8000 miles on it with 2 oil changes. So we booked a trip to [XXX] at considerably a large expense and loaded up our Harley's on my light aluminum trailer, less than 3.5k pounds and headed that way from [XXX]. We made it to [XXX] and spent the night. Next morning we were heading to [XXX] and the truck blew up on the XXX. We were pulled over on a very busy hi way and had to get truck and trailer towed back to [XXX]. We were stuck there for 3 days while GMC installed a rebuilt motor in my 83k truck and totally missed our entire vacation. On line it said GMC would cover hotel and 40.00 dollars a day food. I am so disgusted after being reassured that GMC had fixed the 6.2 and putting our life in danger blowing up on a major highway, and afterward GMC only gave us 200. For our inconvenience. Our room alone was more not counting the money lost on out trip accommodations. I am so completely disappointed with this truck that we bought new and spent more than we ever had on a vehicle, and am afraid of ever taking another trip in it. How can GM be allowed to do this to people. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11762000

Incident

Jul 25, 2026

Engine making noise during a trip took to dealership and they reported engine is bad and needs to be replaced because it would freeze on the road. Vehicle has 7000 miles.

NHTSA ID

11760628

Incident

Jul 12, 2026

ENGINE STARTED KNOCKING AT 18K MILES AND TOOK TO DEALER AND THEY FOUND METAL IN THE FILTER AND INSTALLED A NEW ENGINE AND ALSO REPLACED THE MIDPLATE GASKET ON THE VALVEBODY DUE TO A HARSH DOWNSHIFT WITHOUT CODES IN THE SYSTEM THIS ENGINE IS GOING ON 2K MILES AND IT SEEMS TO BE FINE NOW BUT THE PROBLEM WITH 6.2 WAS ONLY SUPPOSED TO BE ON THE 21-24 MODELS AND MINE IS A 25 MODEL AND ALREADY HAD A REPLACED AND NOTHING FROM GM WAS SAID TO EXTEND THE WARRANTY ON THIS MODEL AND POWERTRAIN

NHTSA ID

11760587

Incident

Aug 14, 2026

FROM DEALER ASSESSMENT Concern - CUSTOMER STATES WHEN VEHICLE IS ACCELERATING THERE IS A RATTLE Correction - test drove and was able to duplicate rattle/knocking from the engine. checked oil level and condition verified both are good. checked for bulletins and followed 23-NA-170. compared vehicle noise to noise is video and noise is nearly identical. removed oil filter and inspected for debris, found heavy amounts of metal debris present in the filter. performed crankshaft end play mesasurement and found that the crankshaft end play is way over spec at 1/4 of an inch. recommend replacing the engine assembly per bulletin Parts) 1x ENGINE 2x (S)GASKET $0.00 $0.00 6x (S)BOLT 1x BOLT 1x exhaust pipe connector gaskets both sides $0.00 8x (S)GASKET 1x fuel feed pipes all $0.00 1x (S)SEAL KIT 1x (S)GASKET $0.00 1x (S)SEAL 1x W-(S)RADIATOR $0.00 1x (S)HOSE 1x coolant $0.00 1x oil filter 1x oil $0.00 Approved 2026-08-18 Labor: $0.00 Parts: $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 Subtotal Line B: $0.00 *Subtotal is before Shop Charge and Taxes

NHTSA ID

11760562

Incident

Aug 17, 2026

Confirmed as catastrophic engine failure by dealership. New engine has been ordered.

NHTSA ID

11760443

Incident

Aug 26, 2026

I own a 2025 GMC Sierra 1500 Denali equipped with the 6.2L V8 L87 engine, VIN [XXX]. The vehicle had approximately 35,000 miles when the engine experienced a catastrophic engine failure. Prior to/during the failure, the vehicle experienced abnormal engine noise and a loss of power. Multiple warning/alarm lights appeared on the dashboard, including the Check Engine and Traction Control warning lights. The engine failure resulted in a loss of motive power and made the vehicle unsafe to operate. PHONE# [XXX] The sudden loss of engine power while driving created a serious safety hazard because the vehicle could no longer operate normally in traffic and could potentially cause a crash. I am requesting that NHTSA document and investigate this engine failure as a potential safety defect involving the GM 6.2L L87 engine. I am also requesting that NHTSA determine whether 2025 GMC Sierra 1500 vehicles equipped with this engine should be included in an appropriate safety recall or other corrective action. The vehicle is a 2025 GMC Sierra 1500 Denali with approximately 35,000 miles. The engine failure and warning lights occurred during normal vehicle operation. The vehicle and repair records can be made available for inspection, and I can provide dealer repair orders, diagnostic information, photographs, and other documentation concerning the failure. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11760197

Incident

Aug 9, 2026

Engine shut off. It did restart after placing it in park. I did own a 2022 Sierra Denali and the motor failed on that vehicle. I swapped out to the 2025 to get away from what I thought was a problem on that vehicle and now learning this is an inherent problem with the 6.2L motors that include this year. As a consumer, I am very infuriated that the problem has been in place for years and still is today. The DOD system in these motors is also a problem and will eventually rear it's head out of warranty. You can go purchase a DOD delete kit and pay someone to remove and install the kit but at an additional 2500 in expense for parts and labor. This needs to be addressed!

NHTSA ID

11759705

Incident

Aug 24, 2026

The 2025 GMC Sierra 1500 with 18,675 miles and the 6.2 gas engine failed during a road trip. I was on my way from [XXX] to [XXX] on the Interstate when about 7 hours in, just outside [XXX]. I was noticing a lack in power when I pulled out of a rest area. The truck would not accelerate over 60mph. I slowed down and as I was pulling off the side of the interstate, the truck died. There was knocking sound as I started to pull over. I attempted to restart the vehicle; it did not restart. I called roadside assistance and the tow truck to myself and the truck into Edwards Chevrolet Cadillac in [XXX]. They diagnosed the issue as spun or bad bearing in the engine, and it would need replaced. They told me that the last 6.2 engine took 60+ days to receive and they were now on backorder, plus they already had a truck in the shop waiting for one. There were no warning indicators on the console, and all my service has been done at GM dealers. The biggest safety issue was being stuck on the side of the interstate with rushing semi's going by. I was also going to be stuck in [XXX] until a resolution was found. I ended up purchasing a new 2026 GMC Denali Ultimate with the 3.0 diesel. It was the closest package that was on my 2025 and I wanted to stay the same, minus the 6.2 engine. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11759266

Incident

Jul 23, 2026

One evening while driving home from work, the transmission warning light illuminated on my dashboard, indicating that the vehicle would soon stop. The notification specifically stated there was a transmission problem. The following morning, I brought my truck to GMC for service. After running a diagnostic, GMC confirmed an issue with the transmission. A few days later, GMC informed me that they were waiting for a replacement part to arrive. The part did not arrive for almost a month. During this waiting period, I was forced to pay for a rental car. Since my truck was still under warranty, GMC should have covered the cost of the rental car for the weeks my vehicle was awaiting repair.

NHTSA ID

11758808

Incident

Jul 15, 2026

On July 25, 2026 when starting my vehicle, it began to shake violently and I receive numerous errors, including a check engine light and displays in the infotainment, indicating there were engine and transmission errors with the vehicle. I received a text message notification and in app notification from GMC indicating that there was a critical error and provided error code P0352. This appears to be an error related to a faulty engine, this is the 6.2L V8, which is known to be problematic by GMC. Had this happened while I was driving on the interstate three minutes later, it could’ve resulted in great bodily harm or death to both myself and the general public around me. GMC was later able to reproduce the issue at the dealer, confirming the faulty equipment on the vehicle with less than 16,000 miles on it. The component was replaced by the dealer, however, the vehicle is available for inspection.

NHTSA ID

11758626

Incident

Jul 25, 2026

The engine shuts off while slowing down. It cuts off cleanly and the entire dash lights up and the transmission shifts to neutral. The driver display says to put the truck in park and hit the start button. After you do this the truck runs fine for about 2k-3k miles and does it again. I has done this 5 times within 10k miles. The dealer says nothing is wrong with the truck because the computer doesn't record any codes. This happens regardless of whether the auto stop/start feature is on or off.

NHTSA ID

11757365

Incident

Sep 10, 2025

Engine started making a loud knocking noise and it sounded like the engine was about to throw a rod. Turned engine off and called GM. Vehicle was towed to dealership and it was diagnosed with a thrust bearing failure. My truck only had 14k miles on it. To fix the bearing issue, it will need a new engine. GM does not currently have engines to replace the faulty ones so it has sat at the dealership for 3 weeks with No ETA as to when it will be fixed. This is apparently a common problem in the 2025-2026 models LZ0 3 liter diesel. They are still selling these affected vehicles currently, knowing that they may have a problem. GM needs to issue a recall and take these vehicles back.

NHTSA ID

11753415

Incident

Jul 10, 2026

Going down the highway at highway speeds engine fully seized up almost cause an accident,, totally locked up engine, got towed to dealer and they said total engine failure just like in the priare years., been waiting for a new engine for almost 3month due to these failing on other cars,, they will be replacing my old engine with same engine that in prone to locking up. only a matter of time till the new one does the same thing. i want a buy back but they say it has 70k miles and its over the warranty and they wont buy back

NHTSA ID

11753374

Incident

May 5, 2026

What component or system failed or malfunctioned, and is it available for inspection upon request? The engine/powertrain failed. The vehicle is a 2025 GMC Sierra 1500 equipped with the 6.2L V8 engine. The engine developed a severe knocking noise and loss of power at approximately 5,545 miles. The vehicle was taken to the GM dealership, where an engine replacement was approved. The failed engine/component may be available for inspection through the dealership or GM, depending on whether it has already been removed or returned to the manufacturer. How was your safety or the safety of others put at risk? The engine failure created a safety concern because the vehicle experienced reduced power/loss of propulsion while being operated. This could have put me and other drivers at risk because a sudden loss of engine power can make it difficult to safely maintain speed, merge, tow, or move the vehicle out of traffic. The issue occurred at very low mileage and without enough warning to prevent the failure. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. The problem was confirmed by a GM dealership. The dealer diagnosed the engine failure and GM approved an engine replacement under warranty. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? The vehicle was inspected by the GM dealership. GM was involved in approving the engine replacement under warranty. To my knowledge, the vehicle has not been inspected by police or insurance representatives. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? Prior to the failure, the vehicle developed a severe engine knocking noise and reduced power/lack of power. These symptoms appeared shortly before the engine failure at approximately 5,545 miles. I do not recall any specific warning lamps or messages before the failure, unless the dealership records

NHTSA ID

11748763

Incident

Jun 29, 2026

The engine blew

NHTSA ID

11744393

Incident

May 9, 2026

Notice during startups and slow speeds engine making taping noises. After bringing my truck in for service I was told my sound was my lifters on the passenger side.

NHTSA ID

11743745

Incident

Jun 8, 2026

Either while stopping while driving or parking (forward or reverse) the engine RPMs go up thus wanting to move the vehicle in that direction causing the breaks needing to be applied harder. When you shift into neutral the RPMs go way up (3000). This has happened on this vehicle 3-4 times of which I have video of the latest occurrence. When put into R or D the RPMs are still over 1000. This also happened on the courtesy vehicle same make and model) I was given but on this one the RPMs went up to 5000 of which I also have a video. The dealership has not been able to duplicate the issue as of yet. My fear is that the vehicle will hit someone or something if the break isn't pressed to the floor. It happens very randomly. The dealer currently has my vehicle trying to figure it out. They say GM says there's nothing they can do. No warning lights or messages appeared.

NHTSA ID

11742881

Incident

Jun 1, 2026

Rough idle started at 11,400 miles. Took to GMC dealer near me and had thrust bearing clearance measured. Measured .0054"(within spec). They released truck back to me. 19,400 mile oil change found large metal(non magnetic) slivers in the filter media. I cut filters to check for issues due to known issues with this engine(metal). I called gmc corporate, i was told to not drive the truck. I paid out of pocket for the tow 142 miles away. Dealer told me they checked thrust bearing and came in at .0055", no noises, and no check engine light. Idle is very rough on start up. GM corporate stated a service advisor will call. Never got a call. I have sent and displayed the evidence and offered to show oil filter contents to both dealer and corporaten both have not done anything about this safety issue. This is a SEVERE safety issue. Engine is highly likely to lock up and cause serious injury to both me, my family, and others on the road. Dealer has released truck back to me and my family with clean bill stating they didnt find anything wrong. They refused to see my documentation of metal slivers or the 3 rimg binder full of maintenance records. As of now i will be escalating this to higher up in GMC corporate. SEVERE safety risk for my family and everyone on the road. GMC dealers refusing to diagnose.

NHTSA ID

11742413

Incident

Jun 2, 2026

6.2L crankshaft failed

NHTSA ID

11741495

Incident

May 13, 2026

In normal operation on Tuesday May 26,2026, the engine experienced catastrophic failure. The engine is the GM L87 6.2 Liter. This was on a highway in the country and I was able to maneuver the truck off the road before an accident occurred. It did leave me stranded and I was required to get it towed on a roll off (It was not drivable) to the dealer where I purchased it. The dealer [XXX] ) inspected my truck and has informed me that the issues with my 2025 Sierra match the issues for the recall GM had for the model years 2021-2025. It will require a new engine, radiator, among many other parts. There weren't any previous warnings. A check engine light only came on once the engine was engine came apart. An oil change on the vehicle by GM was done a month ago. The truck is a 2025 and has approximately 6,600 miles is all. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11740590

Incident

May 26, 2026

My GMC sierra AT4 with the 3.0L Duramax Diesel, has 1,500 miles on it, when the engine failed. I was traveling from [XXX] to [XXX] , towing a trailer, when the check engine light came, and the truck entered reduced power mode. It immediately slowed the truck without warning - which made for a very dangerous situation for all of the vehicles behind me and for my vehicle. After getting the vehicle and trailer to a dealer, disconnecting the trailer, and then getting the truck in the shop, the dealer defined the OBDII code as being P06DD - Engine oil pressure control solenoid valve stuck off. U0146 - Lost communication with central gateway module, and U1605 - Lost communication with side obstacle detection control module - right on private CAN Bus. The dealer indicated that the P06DD code meant that the thrust bearing on the crankshaft failed and the engine would need to be replaced. The ending only has 1500 miles on it. It turns out that there are MANY GM 3.0L diesel engines that have failed for this issue and that GM issued a Technical Service bulletin in 2025 for this issue - TSB 25-NA-307. I work in the medical device industry and when there is a safety issue with your products - you initiate a RECALL. To date there has been no recall simply the TSB. What is the NHTSA going to do about ensuring that GM, and other manufacturers, are making engines safe? These engines can literally explode - sending metal shards through the engine into the passenger compartment. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11738058

Incident

May 7, 2026

15000 miles and the engine spun a bearing and the engine blew

NHTSA ID

11737139

Incident

May 9, 2026