2024 GMC Sierra electrical system problems

“My truck has experienced recurring diagnostic trouble code P244B on [XXX], [XXX], and [XXX], 2026. The latest occurrence included a check-engine warning and reduced engine power. On [XXX], at 40,833 miles, Neil Huffman Chevrolet GMC in Frankfort, Kentucky, diagnosed a damaged diesel particulate filter differential-pressure sensor connector. The dealership's written estimate states that the connector had shorted, begun melting, and had broken wires at the back of the connector. I am concerned about the cause of the electrical overheating, the possibility of additional wiring damage, and the risk of unexpected reduced engine power while driving. I have also experienced intermittent transmission-related warnings and communication fault codes, although I do not know whether these problems are related. I understand there are GM technical bulletins addressing wiring-harness damage on certain 3.0L Duramax vehicles. I am not claiming these bulletins establish the cause of my failure, but I would appreciate having my experience evaluated for a possible safety-related defect trend.”

“At approximately 2 years, 47,000 miles I received a message that I needed to service the transmission soon. I then got a message "Trailer Brakes Disabled Service Required" and another "Service Transmission Now Unable to Shift Soon". I brought the vehicle into my closest GM dealer and they said it is a faulty shift control lever. These are known to have a fault from the factory, but since I am outside of the 36,000 bumper to bumper, they will not cover the cost. It took about 2 months for the part to come in as it was on back order, and now they want $1000 to replace it.”

“While driving on a divided two lane state highway at approximately 60mph my vehicle suffered a catastrophic engine failure causing immediate loss of power in traffic at highway speeds. I had to negotiate highway traffic to steer the vehicle onto a narrow shoulder and continue under reduced power to a location where the vehicle could remain stopped safely. There were no warning signs and no warning lights prior to the issue. The vehicle was towed to Faulkner GMC where it was eventually inspected and determined to be an engine failure consistent with the open recall affecting GM 6.2 L87 V8 engines. A replacement engine was installed under warranty. Additionally, a defective tailgate switch was discovered and replaced. A prior unrelated incident had occurred where the tailgate switch activated on its own lowering my tailgate while the vehicle was in motion. The tailgate lowered onto the tongue jack of a trailer I was towing causing damage to the tailgate. This issue occurred multiple times throughout my ownership of the vehicle until the switch was replaced. GM acknowledged the switch was found to be defective but refused to take responsibility for the damage.”

“My vehicle has experienced repeated and unresolved electrical system failures and unexpected loss of power steering assist. The problem involves multiple warning lights, module communication faults, drivability issues, and simultaneous malfunctions affecting systems including power steering, traction control, transmission, four-wheel drive, and other electronic controls. Repair records, diagnostic information, and videos documenting the failures are available for inspection upon request. The most serious incident occurred on August 23, 2026, when the power steering failed unexpectedly while I was driving. The sudden loss of steering assist made the vehicle difficult to control and nearly resulted in a collision with an oncoming vehicle. The failure created a significant safety risk because it impaired my ability to safely steer and control the vehicle. The condition has occurred multiple times over several months and has resulted in repeated dealership visits. Repairs have included replacement an HVAC controller, but the failures have continued. The vehicle has been inspected multiple times by an authorized dealer, and the manufacturer has been notified through…”

“My 2024 GMC Sierra Denali Ultimate 1500 experienced a catastrophic powertrain failure that created a serious safety hazard. On XXX, while driving at highway speeds, the truck unexpectedly shifted into neutral, causing an immediate loss of propulsion. During this event, the electrical system was also affected. The battery power dropped, power steering assistance was lost, and due to the electronic push-button start system, the vehicle could not be restarted while in this condition. This placed me and surrounding motorists at significant risk of a crash. I initially brought the vehicle to Point GMC, where I was advised no issue was found. After the problem continued, I returned on XXX and a dealership technician rode with me. During the test drive on [XXX], the truck again shifted into neutral, confirming the defect. The vehicle was then towed to the dealership, where diagnostics revealed DTC P0016. I was informed the engine had seized and required a complete engine replacement. The engine was replaced by an authorized GMC dealership in New Jersey. After only about 2,000 miles, the check engine light returned and the vehicle began experiencing additional…”

“My truck has completely shut down/ loss power on several occasions. Happened when I was l slowing down or completely stopped. Everything goes dark. Had to wait several minutes before truck would start.”