While looking for items for the 2020 year coach's I
found this item for a recall on a DSDP looked into it and found the whole 2019 year coach's on the list also.
It has to do with the BRAKE RELAY VALVE AIR FLOW.
The full information in COM_NET Bulletins is 543 RSB RECALL 19V381 many pages of instructions in bulletin.
Many new bulletins have been added since last year when I was in them and I have been saying many times you all should be checking them for your year coach both diesel and gas chassis.
INSTRUCTIONS FOR USE OF COM_NET IN
THIS LINK TOP OF PAGE.