2023 GMC Sierra 1500 Fuel system Problems

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

The truck shut off and would just crank. It threw the code P129F. And wouldn’t start up until after 15 minutes.

NHTSA ID

11764687

Incident

Sep 15, 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

purge pump failing confirmed at dealership this part has been recalled on same truck but not specifically this vin . I was told I need to report it to you guys so that it could ge added.

NHTSA ID

11760943

Incident

Aug 10, 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

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

The fuel pump control module went bad and the vehicle shut off while driving. The vehicle is only 3 years old. Everyone I know with a GM truck or SUV has had the same issue and the dealer service writer even told me they get at least 6 vehicles with the same issue per week. There is already a recall for GM SUV's for 2021-22 model years but not for anything else even though many other vehicles have the same issue. They replaced the module under warranty but it is all but guaranteed to just keep happening.

NHTSA ID

11756888

Incident

Jul 4, 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

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.

NHTSA ID

11746738

Incident

Jun 25, 2026

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.

NHTSA ID

11744918

Incident

Jun 12, 2026

After driving my vehicle for a short period of time I stopped to go shopping. When I returned to my vehicle I started it as usual and the check engine light illuminated. I began driving and within 0.25 miles I received an info enter message that stated my vehicle would have reduced acceleration and to please drive safely. My engine fans became noticeably louder and ran the entire trip home (about 15 minutes). After pulling into my driveway I sat in the vehicle and listen to the fans continue to operate. Additionally, my OnStar system, WiFi, and navigation systems quit working. A P1098 Code was returned when using a diagnostic code device. Disconnecting the battery would cause the check engine light to extinguish and for the truck to operate without reduced acceleration; however, OnStar, navigation and WiFi would not work. After shutting off the engine and then restarting the check engine light would once again illuminate and the reduced acceleration message reappeared.

NHTSA ID

11740519

Incident

May 16, 2026

On 18 March 2026 I was driving at night at highway speed with my family (wife, [XXX] son, [XXX] daughter, and [XXX] son) when, without any warning, my 2023 GMC Sierra AT4 with 20,700 miles abruptly and violently shuddered and reduced speed from approximately 65 mph to 30 mph uncontrollably. Shortly after the initial speed reduction the vehicle presented simultaneous alerts that it was in "reduced acceleration mode", the "emission system control" had failed, and the that the check engine light was on. Although the vehicle claimed to be in reduced acceleration mode I was unable to prevent it from continuously slowing to 0 mph. I attempted to use the accelerator to move from the left lane of traffic to the right shoulder without causing an accident. However, the vehicle violently shuddered and would not accelerate or maintain speed. I managed to maneuver around traffic and stop the vehicle on the right shoulder. Due to the unlit highway and my family's emotional state after the incident, I determined the safest course of action was to attempt to get the vehicle to a nearby parking lot. After turning the vehicle off and back on, I managed to slowly drive with my flashers on (despite the vehicle continuing to violently shudder) approximately 1 mile to a Wal-Mart parking lot. Once there I noticed I received an email from OnStar Diagnostics that my vehicle experienced a significant engine malfunction with an associated P129F code. I coordinated for the vehicle to be towed to Bill Cramer Chevrolet GMC Inc in [XXX] the following day. My vehicle had no lights, messages, or symptoms of this issue prior to it occurring. The dealership replaced the fuel pump power control module under warranty, cleared the faults, test drove the vehicle, and returned to me on 31 March 2026. The dealer mentioned they service roughly two vehicles of similar make and/or models daily for the same issue. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11728466

Incident

Mar 18, 2026

While driving home from Phoenix on Hwy 95, 30 Miles out of Tonopah on the way to Reno engine propulsion and the complete engine failure occurred while driving at 75 mph. No warning at all. No cell service, had to use Onstar to be our savior. Thank God they sent a tow truck, although my wife and I with 2 dogs had to wait 4 hours for the tow truck, while semi’s rolled by us going 80 mph. Dealer performed diagnostics on my truck and has to replace the engine due to engine failure. I had the recall completed in September with the new approved oil and cap. I know this is an ongoing problem with GM’s 6.2 engine. Complete engine failure while driving at 75 mph. No engine warning sign. Screen went blank. I will no longer trust this truck or have any confidence in the truck once I get it back. I sure hope GM pays for this. This has caused me endless anxiety.

NHTSA ID

11723729

Incident

Mar 7, 2026

Getting off on highway and when I got to the light the truck stuttered and shut off. will not turn back on. when I try to start it it stutters and will not turn on

NHTSA ID

11722475

Incident

Mar 4, 2026

On Saturday at approximately 5:30 p.m., while driving on a two-lane city street with vehicles around me, my GMC Sierra began malfunctioning. The gauges flickered, warning lights appeared, and a transmission warning activated. As I attempted to safely pull over, the vehicle began stuttering and then completely stalled in the middle of traffic. Cars swerved and honked to avoid hitting me. Fortunately, no collision occurred, but the situation was extremely dangerous and frightening. AAA towed the vehicle to the GMC dealership. When I informed them of the incident, I received a text asking whether an over-the-air update had been performed prior to the stall. I confirmed the vehicle had received an update within the past three months. I was then told there is a bulletin stating that after an over-the-air update, the vehicle may suddenly lose communication with multiple modules and stall. The foreman indicated this was likely the cause and that they were consulting Technical Assistance. I asked when it is considered safe to drive a GMC vehicle following an update, as I was never warned that the vehicle could suddenly lose power and stall without notice. I was told they were investigating further. Yesterday, I was informed that engineering directed them to replace the ECM (Engine Control Module) and the Fuel Pump Control Module, with the ECM expected to arrive next Wednesday. I have not been given a confirmed timeline for completion. This appears to be a serious and known issue within GMC, yet there has been no recall and no warning provided to consumers. I was unknowingly driving a vehicle susceptible to sudden and complete power loss. This failure placed my life, my family, and the safety of others at significant risk.

NHTSA ID

11721008

Incident

Feb 21, 2026

Driving along a main road at 40-45 MPH and coasting toward a traffic light, the engine stalled out. Traffic light turned green and the vehicle would not accelerate. There were no warnings, check engine lights, or sounds. I could not pull to the shoulder due to traffic and had to pull into a left hand turn lane. The truck would not restart. Electrical systems seemed fine. Engine would turn over but not start on multiple attempts. One attempt finally got it to start but it immediately stalled. I was stuck in a dangerous situation at a busy intersection and no way to move the vehicle. It has been towed to the dealership.

NHTSA ID

11720968

Incident

Feb 27, 2026

Engine lost all power while I was attempting to make a left turn at a very busy intersection. Dash kept saying “check battery”, jump pack did nothing. Engine wouldn’t start.

NHTSA ID

11718939

Incident

Feb 18, 2026

I was driving on an overpass and suddenly loss propulsion in my vehicle. My vehicle stopped all of a sudden and while driving, leaving me stranded in the middle of the roadway blocking traffic. Numerous motorists stopped to give a hand but the vehicle would not switch gears from PARK, to neutral to even give me a hand moving the vehicle out of the roadway to the side/shoulder. Due to this issue, authorities were dispatched to my location to conduct traffic control and subsequently called in aide of a tow truck to safely move my vehicle to a better location. I used OnStar in my vehicle and also spoke with a representative who notated the incident and I was advised that a tow truck would take approximately 90 mins to 2 hours to reach me. In this instance, that was too long of a wait for events going wrong with the vehicle itself and was subsequently transferred from the roadway to a GMC dealership, namely Group 1 South on the Gulf Freeway. They are handling my repairs and have diagnosed that the engine needs to be completely replaced and are in the process of repairs. If any information is needed regarding status or repairs, please contact the dealership directly as I do not have any physical or written information on the status of my vehicle. Attached is the towing receipt.

NHTSA ID

11715606

Incident

Jan 23, 2026

Engine shut off on the interstate with no warning. Would not re-start. Forced to cross lanes on traffic with no engine power or power steering. Dealer stated it was the "Fuel Pump Control Module." Stated it was a common issue with parts most likely in stock, but it would be at least 6 weeks before they could even look at the vehicle.

NHTSA ID

11714981

Incident

Sep 8, 2024

Vehicle stalled out, lost power, left me stranded on side of road. No warning, check engine lights or any other inclination prior. Turn out to be fuel pump control module.

NHTSA ID

11707207

Incident

Dec 25, 2025

ECM - Engine System code P0700 and TCM - Transmission System code U0073. The truck went in to first gear and wouldn't go over 5 MPH on the highway. The dealer is saying it can't be replicated but it's happened multiple times to the vehicle in the past week. The truck was taken to the dealership and inspected but they claim nothing is wrong. The check engine light came on as well as the aforementioned codes.

NHTSA ID

11698192

Incident

Nov 4, 2025

While stopped at traffic signal, vehicle suddenly stops running. Restarted vehicle and had to feather the throttle to keep it running. Engine began to run normally so I continued driving. When I reached approximately 35 mph, a loud rattling noise started and experienced a severe loss of power. Fortunately I was able to safely get out of the traffic lanes to the side of the roadway. I inspected the vehicle, no oil leaks, no coolant or transmission leaks. No warning indicators on the dash. Oil pressure normal. Temperature normal. I limped the vehicle home to be towed to dealer. Approximately 2 months ago this vehicle passed the recall inspection and had the recommended oil change. There was a previous warranty repair performed on a stuck exhaust valve in the #8 cylinder. The vehicle was also brought in to the dealer for suddenly cutting off while driving approximately 50 mph. Again I was able to pull off safely. The vehicle then started normally and I proceeded to drive. The dealer inspected the vehicle and could not replicate the issue, and found no electrical or mechanical trouble codes. There were absolutely no warning indications prior to each of these events.

NHTSA ID

11697942

Incident

Nov 5, 2025

The vehicle has suffered repeated systemic electrical failures all while being under 8,000 miles. What component/system failed? Power distribution/fuse block, starter, fuel pump control module, horn circuit, body control module, instrument cluster, and charging system. Error codes documented include P0627 (Fuel Pump Control Circuit), U0100 (Lost Comm ECM/PCM), B1325 (Control Module Power Low), U0140 (Lost Comm BCM), and B1000 (ECM fault). All repairs are documented by the dealer, and the truck remains available for inspection. How was safety at risk? The truck lost propulsion at speed, emitted smoke from the engine bay, and became disabled in traffic, placing my family, including my toddler, in immediate danger of collision and fire. Electrical defects also disabled horn and instrument cluster, removing critical warning and signaling functions. These electrical issues have been ongoing for months and GM refuses to replace and can't seem to fix it. Has it been confirmed? Yes. Each failure was diagnosed and confirmed by an authorized GM dealer. Components replaced include fuse block, starter, fuel system computer, horn assembly, and cluster. Despite repairs, issues recur. Inspected by others? GM corporate case managers are aware and have acknowledged defects, though they have refused to issue written determinations. Insurance has not yet been involved, but records are available. The dealer has attempted to repaid more than 4 times with no success. Warning lamps/messages? Yes. Prior to and during failures, vehicle displayed repeated “Service Electrical System,” “Low Voltage,” and communication fault codes. Cluster intermittently blacked out. Smoke in engine bay indicated immediate fire hazard. Cumulative out-of-service days exceeding 20. The failures pose unacceptable risk of fire, sudden propulsion loss, and loss of critical safety functions. I have ALL calls with GM recorded and transcribed as I am in SC (single party recording state) and can provide those.

NHTSA ID

11687675

Incident

Aug 18, 2025