2023 GMC Yukon electrical system problems

“I have a 2023 GMC Yukon SLT. The OnStar/telematics system stopped working. The blue OnStar button does not function, and the vehicle no longer communicates with the myGMC app, resulting in the loss of OnStar and connected services. A GMC dealership diagnosed a failed OnStar/telematics module and advised that replacement will cost approximately $1,200. This creates a safety concern because OnStar provides emergency services, including Automatic Crash Response and the ability to request emergency assistance from inside the vehicle. A module failure could leave an occupant without access to these services when they are needed most. I am also concerned that OnStar and telematics failures appear to be reported by owners of multiple GM vehicles, suggesting this may not be an isolated failure. I am requesting that this issue and similar complaints be investigated to determine whether there is a broader defect requiring a recall, warranty extension, service campaign, or other corrective action.”

“I have a 2023 GMC Yukon that has been to the dealership 3 times in a weeks time, and as of today, 8/31/26 will be the fouth time. On 2 occasions, the SUV has entered Limp Mode while driving. I had the SUV towed for the first limp mode, and the dealer claimed it needed recalibration modules. I picked up the car and drove home eight miles, and the check engine light came on. I returned the next day for readings and TCM P0700, P1789, U0101, U220F. The dealer's solution was to recalibrate the gateway module this time. I drove the car about 20-ish miles, and at highway speeds on the freeway, I got limp mode again. Off to the dealership, having the SUV towed again. The dealership has claimed the electrionic car codes clear themselves and because of that they can't re-create the codes to find a solution. I am scared to drive my SUV, I do not feel safe in it let alone my children.”

“On August 22, 2026, I was driving my 2023 GMC Yukon Denali with the 6.2L V8 at highway speed when the vehicle began struggling to maintain power while climbing a hill. The engine then developed a noticeable knocking sound. Shortly afterward, the engine shut off completely while the vehicle was moving, causing a sudden loss of propulsion. I was able to bring the vehicle to a stop, but the engine would not restart. The electronic transmission also would not shift into Neutral and displayed a message indicating that the conditions required to shift were not met. Because the vehicle could not be shifted out of Park, the towing company had difficulty loading and unloading the vehicle. The failure occurred during normal highway driving and created a significant safety concern because the engine shut down without warning while the vehicle was in motion. I am aware of NHTSA Recall 25V-274 / GM Recall N252494000 involving certain GM vehicles equipped with the 6.2L L87 engine, as well as NHTSA Engineering Analysis EA25-007 concerning engine failures and loss of propulsion. At the time of this complaint, the dealership has not yet confirmed the specific mechanical cause…”

“I have a 2023 GMC Yukon AT4. The OnStar/telematics system stopped working. The blue OnStar button does not function and the vehicle no longer communicates with the myGMC app, resulting in loss of connected and OnStar services. A GMC dealership diagnosed a failed OnStar/telematics module and advised that the module must be replaced at a cost of approximately $1,200. I am concerned because this failure affects access to OnStar communication and emergency-related services. I have found reports from other GM owners describing similar telematics/OnStar module failures, and GM has issued service information addressing K73 telematics-module communication faults. I have also opened a case with GMC Customer Assistance. I am reporting this because I believe the repeated failure of a system used for emergency communication warrants investigation.”

“On June 25, 2026 my 2023 GMC Yukon Denali with 53,456 miles was brought to an authorized GMC dealership after displaying a Service 4WD warning light and exhibiting a groaning noise when shifting into Drive and Reverse. The vehicle was diagnosed with the following brake system fault codes: P25A2, C0511, C0517, C1595 and C1596. These codes indicate brake control module failure and wheel speed sensor faults which are safety critical components. The dealership confirmed these findings but stated the repairs are not covered under the GMC powertrain warranty. Given that these are safety critical brake system failures on a nearly new vehicle with only 53,456 miles, we contacted GMC Customer Care on July 1, 2026 to request coverage under goodwill warranty as we believe these failures constitute a manufacturing defect. A case was opened however after 7 days no case advisor has been assigned and no decision has been made despite two promised timelines not being met. The brake system failures on a nearly new vehicle represent a serious safety concern as these systems directly affect the vehicle's ability to stop safely. The vehicle has been at the dealership since June…”

“The contact owns a 2023 GMC Yukon. While the contact's wife was driving approximately 5-10 MPH on a city street and approaching a stop sign, the vehicle experienced a failure and became inoperable. The contact stated that while the driver was attempting to restart the vehicle, the battery warning light and engine warning light illuminated, and the "Low Battery - Start Engine" message was displayed. The vehicle was towed directly to a dealer to be diagnosed. The dealer was unable to determine the cause of the failure but provided an estimate for the valve springs inspection. The vehicle was not repaired. The manufacturer was notified of the failure and was working with the dealer to determine how to repair the vehicle. The failure mileage was approximately 71,481.”