2023 GMC Acadia

My 2023 GMC Acadia experienced a complete electrical system failure while driving on an interstate highway. During the incident, the vehicle lost all electrical power, including hazard lights and steering assistance, and could not be shifted into neutral. The vehicle became immobile in active traffic and required police-ordered towing due to safety risk. This incident was the second alternator failure within six months. The second failure involved a GM-installed replacement alternator that failed prematurely. Both incidents required towing, and the second created a significant roadway safety hazard.

While driving under normal conditions, the vehicle experienced a sudden, violent deceleration. The emergency braking and collision avoidance systems activated spontaneously, as if the vehicle had struck or was about to strike an object. There was no obstacle, impact, or external threat present. This uncommanded braking caused significant physical stress and injury to the occupants. Critically, multiple safety systems failed during the event: The seat belts did not lock, failing to restrain the occupants; The airbags did not deploy, despite the severity of the deceleration; no warning indicators or diagnostic alerts were present before or after the incident. These failures directly contributed to physical injuries, including TBI (concussion, spinal trauma, etc.) which required emergency medical treatment and ongoing care.

I've had the engine stall before coming to a complete stop on several occasions. It also has been shifting hard and has had a delayed shift. The other day all of the lights to to screen and speedometer completely went out while driving then randomly came back on. That's the only speedometer I have is the digital screen.

I am experiencing a recurring P04FB diagnostic trouble code on my 2023 GMC Acadia, related to the crankcase pressure sensor. GM issued Bulletin No. PIP5841C, which attributes the issue to moisture buildup freezing inside the sensor. Their recommended fix is to remove the sensor, blow out any moisture, and reinstall it. However, this is not a permanent solution—the code returns within days, suggesting an inherent design flaw in the PCV system. Additionally, the replacement sensor (Part #12718935) is on national backorder, making it impossible to obtain. Many owners across multiple GM models using this engine (such as the Chevrolet Blazer and Cadillac XT4) are experiencing the same problem, yet GM has not provided a real solution. A properly designed PCV system should not allow excessive moisture to accumulate in the sensor. Instead of addressing the root cause, GM’s bulletin merely delays the issue by temporarily clearing the moisture. This approach does not prevent the problem from recurring, and it does not fix the underlying defect. If the sensor fails or provides inaccurate readings, it can affect emissions and engine performance. The fact that the replacement part is unavailable suggests GM may be restricting access to it, possibly because they know it is defective. This raises concerns that GM is quietly managing a widespread issue rather than issuing a formal recall or warranty extension. I am requesting that the NHTSA investigate this issue, as GM's current approach does not resolve the problem. Owners should not be forced to repeatedly clear moisture from a sensor that is failing due to a design flaw. If GM has internally identified a better solution, it should be made available to affected owners instead of delaying action with ineffective temporary fixes.