2023 GMC SIERRA 1500 Complaints

OnStar module failed. Unable to fix and needs replaced. Thousands of other individuals having same issue. Car can shutdown without warning while driving. This issue must be addressed by GM.

On March 3rd 2026, I went to a doctors appointment. Halfway into the 50 minute drive, I noticed the on the infotainment screen that my GPS was still showing me being at home. It was working normally a couple days prior to parking the truck. After my Dr appointment, I did some online research and followed recommended procedure to do a hard reset of the infotainment/radio to try and refresh the signal. Didn't work so I checked the recommended fuse and it was good. Realized that the OnStar and truck's cellular/data was also not working. After more research, I found that it's a very commonly reported issue on 2022-2024 trucks. Apparently the Telematics module will freeze/glitch or fail. Took my truck down to American Chevrolet on April 13th for the Data Gateway Module recall# N242435631 and asked their service advisor if he could find out what's going on. After the recall was performed, he verified that the Telematics module is indeed dead but, because I'm at 39,000 miles, they could not fix it at no cost. The biggest reason why I've been driving this truck so frequently is because it's the safest truck we have and the Automatic Crash Response & Emergency GPS gives my girlfriend some piece of mind when traveling with our two sons. She now refuses to travel with me in the truck. I'm also upset that the cellular data is paid up until I believe March of 2027 and now I can't use services paid for but, I'm more concerned about the safety features that are no longer working. For this part to completely fail or lock up at under 40k miles is absolutely absurd. I'm going to request a Good Faith repair through GMC but, I want this to be documented. Thank you for your review of this problem.

I was driving down the road at 55 mph on 4/12/2026 and had let off the gas for a 45 mph zone when I experienced a violent downshift of the transmission that squealed the tires momentarily and felt like someone had hit me from behind. It startled me and caused me to lower my speed down to 20 mph. I continued driving to my destination and when I let off of the gas doing 45 mph for a slight curve I had another violent downshift that felt again like someone hit me from behind. I contacted a GMC dealer on 4/13.2026 to see if there was a recall on the transmission that I wasn't seeing online and was told no. I described what I experienced to their service department and was told to flush out the transmission fluid and replace the filter. I did experience another bad downshift at a slower speed (about 25 mph) on 4/13/2026. There wasn't any warnings or lights that came on when these three incidents occurred. When looking online I did see there was a similar recall for 2020-2022 GMC Sierra's where customers were experiencing similar violent transmission downshifts and am wondering if this issue is affecting more than just those three model years.

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.

The plastic piece above the front grill detached and flew off the truck. I’m not sure the name of the part.

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.

The contact owns a 2023 GMC Sierra 1500. The contact stated that while driving on several occasions at speeds above 30 MPH, the vehicle shuddered abnormally. There was no warning light illuminated during the failures. The vehicle was taken to a dealer, where it was diagnosed, and determined that the valve body needed to be replaced. The vehicle was repaired, but the failure recurred approximately six months later. The manufacturer was notified of the failure. The failure mileage was 81,000.

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)

While driving under normal conditions, a front grille trim component detached from my vehicle without any impact or external cause. The piece became airborne and struck my windshield, creating an immediate safety hazard and risk of loss of control. There was no prior damage or warning. This represents a failure of a vehicle component under normal operation and indicates a defect in materials, design, or installation. Exterior parts should not detach and become projectiles at roadway speeds. The manufacturer has been notified but has declined responsibility. Given the safety risk, this may not be an isolated issue.

My vehicle is a GMC Sierra 1500 Duramax diesel. The vehicle experienced a failure of the DEF (Diesel Exhaust Fluid) system, which was diagnosed by the dealership as a failure of the DEF tank heater. The heater is integrated into the tank assembly, requiring full replacement of the DEF tank. As a result of this failure, the vehicle became unusable and has been out of service since March 3, 2026. The dealership confirmed that the required part is on national backorder with no confirmed availability date. This condition creates a significant reliability and potential safety concern. When the DEF system fails, the vehicle can enter a reduced power or speed-limited mode, which may occur during normal driving and could create unsafe conditions in traffic. Additionally, there appears to be a broader pattern of similar failures affecting other vehicles of the same type, combined with extended delays in obtaining replacement parts. The lack of parts availability results in extended periods where the vehicle cannot be safely or reliably operated.