2023 GMC Sierra 1500 Driver assistance Problems

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

The front grille trim moulding failed and flew off on the highway. Also, the forward collision light on vehicle from the front camera not working and needing to be replaced.

NHTSA ID

11764036

Incident

Sep 1, 2026

Purchased above listed vehicle new in XXX. Immediately noticed a 'coolant' smell in cab. brought vehicle in for coolant smell issue on XXX and XXX. We were told that there was no issue until finally on XXX we were told the radiator needed to be replaced at OUR expense. XXX we received a letter from GMC advising the "engine coolant control valve" may fail. In XXX while driving on mountain roads (we live in [XXX]) the check engine light came on and while at 50 mph, the vehicle went into "limp mode" we lost power and speed was immediately reduced. We now know that a symptom of that valve failure is coolant smell in the cab of the car, a problem we had attempted to address with GMC from the beginning. We could have had a serious accident driving on a busy mountain road when this failure occurred. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11763393

Incident

Sep 1, 2026

This vehicle has water intrusion for the power steering harness. The system went out one day. Vehicle has 40K miles on it. i bought it less than a year ago as a used vehicle with 30K miles on it. Less than a year later i end up with a $6,500 bill for it.

NHTSA ID

11763381

Incident

Aug 17, 2026

I was driving my family on the highway and my truck completely shut down. The screen flashed a warning and it slowly started decelerating. Thankfully I was able to make it to the shoulder of the road safely. Engine failure was a known safety issue with my model of truck, but I completed the L87 Engine Loss of Propulsion safety recall testing on 9/18/2025 and was assured my engine passed the testing and was not at risk for engine failure.

NHTSA ID

11748693

Incident

May 24, 2026

The truck side toy down shift and the accelerator was very high…. When I was going to park the reverse was not shifting…

NHTSA ID

11741918

Incident

May 28, 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

I brought this truck brand new. Had issues the first couple days of purchase that was a quick fix, but as time went on things got worse. Truck always stalling out, engine has been replaced once already due to a recall and months after the first replacement, it stalled out on me again in the middle of the freeway and I just got a call from the dealership that it needs another new engine! How is this right! How is this safe! I could've lost my life on every occasion it has happened.

NHTSA ID

11732074

Incident

Apr 4, 2026

The contact owns a 2023 GMC Sierra 1500. The contact stated while reversing, the rear-view camera displayed a black image, and a message advising that the rearview camera was unavailable, was displayed. The contact stated that upon depressing the brake pedal, the rear-view camera screen reset independently. The vehicle was taken to the dealer; however, the failure was not diagnosed. The contact stated that the dealer inspected the wiring harness and the rearview camera display but found no failure. The manufacturer was made aware of the failure, and a case was filed. The contact stated that an engineer was assigned to inspect the vehicle. The engineer performed an inspection; however, the cause of the failure was not determined. The vehicle was not diagnosed or repaired. The failure mileage was approximately 37,188.

NHTSA ID

11730376

Incident

Jun 19, 2025

Mileage

37,188 mi

On March 13, 2026 I purchased a 2023 GMC Sierra AT4 Pickup with 3.0 Diesel Engine. While driving on a state highway in a 35 mph zone I started to accelerate as the speed zone changed. The truck suddenly had the rear wheel lock up for a brief time about quarter to half second then the truck proceeded on. This happened as the transmission was downshifting. Then on or about March 24, 2026 I was using the same truck and towing a 4,000 pound enclosed trailer. This trailer was hooked up within all recommended hookup requirements. In a 225 mile trip I experienced the same rear wheel lock up happen 4 random times during the trip. Once this happened at 65 miles and hour had there been snow or ice on the highway the truck may have crashed. This lock up happened while using the truck in tow haul mode. Two times it happened while the truck was being towed with cruise control active and two times it happened while not using cruise control. Truck was brought to Authorized GM Dealer and inspected and truck had no stored codes from transmission related issues. Dealer blamed this for using cruise while towing. I informed dealer this happened while not using cruise as well. Was told to turn off adaptive cruise when towing. I was unable to find anything in the GMC Manual regarding not using cruise while towing. This appears to be an issue with the valve body in the transmission and customer explained this to the dealer but they denied this claim. When these quick moment lockups happen no codes or engine lights show everything on dash appears normal. Customer is bringing truck to another GM Dealer to be tested and examined.

NHTSA ID

11729261

Incident

Mar 24, 2026

My 2023 GMC Sierra has 60,571 miles for a while now while driving the transmission slips and slams into gears. Recently driving with my kids in the car on highway going 70mph the back brakes locked up multiple times, so scary and dangerous while driving. I now currently have a code P-0747 in the system.

NHTSA ID

11724873

Incident

Mar 8, 2026

This complaint involves a sudden failure of my vehicle’s Anti-Lock Braking System (ABS) and Forward Collision Warning system, both of which are critical safety systems. While driving my [XXX] son to school, multiple warning lights suddenly appeared on the dashboard without any prior indication of a problem. The vehicle displayed a warning message instructing me not to exceed 36 miles per hour, and several system alerts activated simultaneously, my ABS brake system failed and a transmission failure warning. These issues appeared suddenly while the vehicle was in normal operation. Prior to this incident, the vehicle had been functioning perfectly. The evening before, I had driven the vehicle to pick up my son from wrestling practice with no issues. The following morning, during a routine trip to school, these critical safety warnings appeared without warning. Because the warnings involved the braking system, I immediately took the vehicle to Beach Buick GMC for inspection. The dealership diagnosed the issue as a software failure affecting the braking system and informed me that the vehicle required a software update and system download in order to restore proper operation of the brakes and related safety systems. I was required to pay over $300 for this repair because my vehicle is approximately 3,000 miles outside of the warranty period. However, I believe a failure involving the braking system and safety warnings should not occur suddenly in a properly functioning vehicle and should not be treated as a normal maintenance expense. I contacted **General Motors customer service to ask why a failure involving a critical safety system would not be covered or investigated further. The only explanation provided was that the vehicle was outside of the warranty period. I requested a written explanation of their decision for my records, but I was told that providing written explanations is against company policy. I have more to say but I am out of characters... INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMA

NHTSA ID

11723265

Incident

Feb 3, 2026

Onstar module stopped working

NHTSA ID

11718685

Incident

Feb 12, 2026

The contact owns a 2023 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle shuddered while in first gear. The contact stated that the transmission sounded strained and shifted rough before slamming into gear. The vehicle was taken to the dealer; however, no cause for the failure was found. The dealer diagnosed the vehicle and determined that the vehicle was oversteering while turning to the right. The dealer replaced the valve and torque converter. On another occasion, while driving at an undisclosed speed, the vehicle accelerated independently. Most recently, a burned transmission fluid odor was coming from the front of the vehicle and entered the cabin through the A/C vents. There oil stains found on the ground on several occasions. The vehicle was taken back to the dealer and the valve body was replaced, the fluid levels were checked, and the transmission filter was replaced; however, the failure persisted. The contact called the dealer, and the dealer towed the vehicle. The dealer determined that the oil cap was loose. The vehicle remained at the dealer unrepaired. The manufacturer was made aware of the failure, and a case was opened. The failure mileage was 8,496.

NHTSA ID

11715151

Incident

Oct 8, 2025

Mileage

8,496 mi

Vehicle will show lane keep assist system as active but provide no intervention and allow vehicle to travel into the next lane intermittently. System will also move itself to the next lane unexpectedly when near the lane markers of the original lane. Navigation system and radio will freeze, stop working all together, and at times fully reboot, randomly while in operation. While these issues are frequent, they are intermittent. No repair suggestions by dealer or manufacturer

NHTSA ID

11714987

Incident

Sep 19, 2025

This malfunction is ongoing and the dealership cannot fix the problem. The first time it happened in September 2025. I was driving down the road and the gauges started to go crazy. The screen on the dash said reduced acceleration. Then it said Service ESC. Then it said Service Traction Control. It would not let me go over 40 mph. I took it to the dealership and they told me I needed a valve body replacement. They installed the valve body and that did not fix the problem. It happened again and said reduced acceleration took over forcing me to pull over on the side of the road. The GMC dealership said to bring it in again but they could not reproduce the malfunction after driving for a week. It happens randomly. The third time this happened I was traveling up interstate 24 at about 70 mph. There were semi trucks around me when the malfunction happened and my acceleration and speed was reduced throwing the RPMs as high as they would go, and I was almost hit by a semi trying to move out of the way and onto the shoulder of the interstate I tried to accelerate to get out of the way of the semi truck but could not. I had to swerve over almost losing control of my truck. I informed the dealership that this had happened again and they asked me to bring it in. I did. They told me they were going to clean corrosion off of ground wires, and that should fix the problem. It did not. This keeps happening and I feel that the vehicle is not safe to drive. I do not know when it will happen again. I travel for a living and I feel the vehicle is unsafe to operate.

NHTSA ID

11713221

Incident

Sep 12, 2025

The contact owns a 2023 GMC Sierra 1500. The contact stated that on several occasions while in reverse(R), the rear-view camera was fuzzy, obstructing the view of the rear of the vehicle. On several occasions, while the vehicle was in reverse (R), the camera was fuzzy, and after shifting to drive(D), the front camera displayed a black screen with a camera and a RED line. The vehicle was taken to a dealer; however, the cause of the failure was not determined after 8 weeks. The manufacturer was not notified of the failure. The failure mileage was approximately 34,000.

NHTSA ID

11681270

Incident

Jun 16, 2025

Mileage

34,000 mi

Driving on the highway under normal driving condition, my check engine light came on and said service transmission. This then put the truck into "limp mode" and I was stuck going 60mph in a 75mph zone. Dealership scanned and found that the coolant sensor control flow valve is faulty. This part is in such demand for these vehicles that it is unknown when the part will be in.

NHTSA ID

11671349

Incident

Jul 2, 2025

The active cruise control does not appear to be able to be completely turned off, you can only cancel a particular speed you have set. I have experienced multiple times in a parking lot situation when trying to park that as steering wheel was spinning, it is very easy to hit the toggle switch that sets/resumes the cruise control, at that point vehicle may acclerate to the set point as you are trying to park. You must quickly either hit the cancel button or the brake to disengage the cruise control that you have no intention of engaging. Although I have been able to get the situation under control, had another moving car or pedestrian been close by, not sure if I would have same result. I have gone through the operating manual provided with the vehicle, and from what I can tell, there is nothing in the manual that even tells you how to operate the active cruise control. It seems like there needs a “system off switch” so the set/resume button is not active, until the system is turned on. I have owned many GMC Products, and none have had the design where the toggle switch sticks out from the steering wheel and is easily inadvertently engaged. Usually the controls are flat/smooth like the “cancel” button on this vehicle…….which can’t easily be engaged accidentally. Luckly, I have not had a crash or injured a pedestrian

NHTSA ID

11663971

Incident

May 26, 2025

While driving on the interstate, my vehicle started losing speed. I pulled over to the shoulder of the interstate and put in neutral so I could coast further to the exit ramp where I would be in a safer location. My vehicle has 14037 miles on the odometer and has now gone through 2 engines. It has always been serviced by GM.

NHTSA ID

11641203

Incident

Jan 27, 2025

The issues with my vehicle began when the radio intermittently cut off or froze. Despite several attempts by the dealer to resolve the problem, they were unsuccessful. Early on, various electrical components failed to load or perform correctly, with the dealer attributing this to software updates. Currently, when the radio cuts off or freezes, I experience additional problems: the headlights randomly flash between dim and bright, the heads-up display fails to load or shows incomplete information, the collision detection activates with no objects around, and dynamic cruise control becomes unreliable or fails to engage. The wipers operate randomly, and the vehicle stalls when the auto start/stop feature is engaged. Random warning lights appear on the dash, and each day brings new, different issues. A new symptom involves the vehicle not recognizing the keys are inside, causing it to shut off and lock me inside. This recently happened while I was driving at low speed in a parking lot, which poses a serious safety risk. On the interstate, safety issues are more concerning: headlights flashing on and off, dynamic cruise control failing, BLIS and collision control activating unexpectedly, and the vehicle locking me inside with keys in the truck. My children are scared to ride in the vehicle due to these issues. The dealer claims they cannot replicate the problems, despite videos I’ve provided showing malfunctions. They acknowledge the issues but blame them on software updates. Multiple updates have been applied, but the problems continue and are becoming more frequent, affecting more systems. The vehicle is under warranty, but as of December 13, 2024, the dealer has refused to service it. After the dealer completed some work, an independent inspection confirmed the issues persist. Warning messages and malfunctioning lamps have been captured on video. Problem has been reported from first service approximately 6/2023 as radio malfunction / electrical issues

NHTSA ID

11630691

Incident

Dec 14, 2024

Purchased vehicle new June 23 2023 and Super Cruise never worked and if engaged acted erratically . Vehicle spent over 40 days in several GM dealerships for the issue and one dealer even charged me for installing a warranty part.. GM filled a case 9-10220813020 but were not helpful in dealing with dealers and to add insult to injury would not even reimburse me for warranty work or in any way compensate me for my time and efforts to fix the issue. Frustrated with GMs indifference I traded the vehicle in March 2024.

NHTSA ID

11584185

Incident

Apr 20, 2024

The contact owns a 2023 GMC Sierra 1500. The contact stated that while operating the vehicle, the rearview camera, front view camera, and side view cameras became inoperable. The vehicle was taken to the local dealer to be diagnosed. The contact was informed that the camera module needed to be replaced; however, the part to fix the vehicle was not available. The manufacturer was notified of the failure. The failure mileage was 8,500.

NHTSA ID

11575712

Incident

Jan 15, 2024

Mileage

8,500 mi

Front blind spot visibility is dangerous and GMC does not provide a forward facing camera standard. Blind spot warning also not standard and visibility is subpar.

NHTSA ID

11558188

Incident

Dec 3, 2023

Traveling at 70 mph on cruise control, tapped breaks to turn off, multiple warning lights flashed, vehicle lost power, and breaks with multiple messages including “Break system failure, top speed 62 mph”. I lost all breaking control on the highway and nearly crashed into other vehicles due to inability to stop. Was able to pull over, turn off vehicle, and turn back on, when the breaks were working again but the vehicles acceleration was very slow. Currently at authorized repair shop. When dropped off, there were 8-9 active codes.

NHTSA ID

11545089

Incident

Sep 14, 2023