Fascinating defect
I presume you have observed this discussion?
The audio circuit is responsible for an unwanted battery drain; what are the solutions?
Indeed, Mk4 compared to Mk5, yet there might still be some utility. It appears that this issue is relatively prevalent.
I'm unclear about your reference to "All fuses out," but please review that discussion. The auditory apparatus... I have encountered analogous erroneous diagnostic codes stemming from electrical system malfunctions on one of my Mk4.5 vehicles; for instance, I received persistent "Water in Fuel" alerts and General Electrical Faults, which ultimately were traced back to a faulty (intermittent) ground connection at the Trailer Light Control module. Thus far, at least...
To be honest, I find myself somewhat perplexed regarding your current situation, but it may be prudent to temporarily overlook the information provided by Forscan and several battery chargers.
I would begin anew with the fundamentals to ensure clarity. Verify the parasitic current consumption. Adjust your DMM to the 2Amp setting and utilise high-quality crocodile clips to establish a secure connection between the Chassis and a point along the Battery Ground cable. Deactivate the vehicle, allow it to enter sleep mode, then detach the Battery Ground connection from the chassis, ensuring the DMM clips remain attached to prevent the car from detecting a battery disconnection and maintaining its sleep state. Subsequently, observe the actual current draw you are receiving.