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.

- White Lake, MI, USA

Purchased Vehicle Oct.21 2022. In first week, vehicle left my wife stranded twice, and myself once. When error occurs, vehicle goes into limp home mode and cluster illuminates all lights, says serivce brakes, transmission, engine, fuel tank reads "E" (when is was just full), PRNDL buttons are flashing and will not allow park, does not respond to throttle inputs... only way to be not stranded as the vehicle will not restart is to disconnect battery or wait 15-20 minutes as the vehicle seems to incorrectly "heal" its errors and allow the engine to restart. I noticed this when the tow truck came to pick it up, and he "drove" it on to the flat bed. 45 Diagnostics showed up on the scan tool, all relating to CAN bus communication. My concerns are the following: 1. How can a 2023 vehicle with <400 miles leave some one stranded 3 times because of a CAN bus comm error? There is an electrical gremlin (likely from lack of quality control) causing to leave a customer to having to limp to the side of the highway. 2. Why is the error able to incorrectly "Heal" itself, ie. the fault reactions seem to debounce and allow engine to restart (as mentioned prior) after a certain amount of time. This only leads to potentially putting the customer back at risk as they just were. 3. GM dealer is yet to start troubleshooting, its been 2.5 weeks. Claim is that they "need a transmission guy to look at it since the codes causing the check engine light are transmission module". Although, the vehicle has approximately 45 active codes, relating to many different modules and all pointing to CAN bus error. The vehicle has an electrical issue, causing my wife to get stranded. first warning on cluster before being stranded : "Service: Transmission Now Unable to shift Soon. " What does this even mean"??" this does not tell me, what the problem is, and what I should do about it. I am an experienced OBD Engineer from an auto OEM and this does not follow best practices. Please help.

- Livonia, MI, USA