SD Connect Device not in use & DAS Fault (1.2)-2.503.9901 Solution

These are Mercedes MB Star diagnosis DAS and MB SD Connect C4 communication solutions by obd2tool technicians:

DAS Fault (1.2)-2.503.9901 with the error “Communication failed”


MB SD connect c4 main unit displays “Device not in use”


This issue usually can be solved as follows:

– re-set IP address:

1) Connect MB SD Connect C4 with LAN cable
2) Open Virtual Network Editor and use vmnet0 (Auto-Bridging )
3) Install (2 ) Local Area Connection
4) Set IP:

Local Area Connection ( 1 ) IP 172.29.127.XXX this for IP MUX
Local Area Connection ( 1 ) IP 192.168.1.XXX this for IP network or IP Network you use

5) Make configuration for SD connect wireless,

(SD C4 usually solve the issue after IP re-match)

– setup the PC date

The date must be the same as the software version

E.g. Your DAS is 2016.09 version, then your PC date should be 2016/09

– replace the Config file in c:\program\mecredes-benz\config

(this is for Mb Star C3 users)

STAR C3 Config file download



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