James Matus and The Werk Shop were able to correctly diagnose multi-function display lockup
on my 2010 S 550 Mercedes. Red color message said "Battery Not Charged" and would not go
away after checking alternator and battery. Both were good.I was misinformed by dealer that if
message did not disappear in a few days that my alternator was bad. After diagnostic testing
The Werk Shop found that I needed a new sensor and SAM - signal acquisition module. Both
were replaced. The SAM had to be ordered and specifically programmed at factory and shop
for my Mercedes VIN. Right now my S550 and complex electrical CAN are operating very well.