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No Connection to The SDconnect Can Be Established (749) for Mercedes SD Connect C4 SN:101044 Solved

No Connection to The SDconnect Can Be Established (749) for Mercedes SD Connect C4 SN:101044 Solved

MB sd connect c4 is hot-selling diangostic and programming tool for mercedes benz cars and trucks. Mercedes sd c4 comes with different serial number. We have the sd c4 with SN: 100925 hot-selling and can support firmware online update. While not all the star diagnostic tool can support firmware update online. One of our customers meet this firmware update failure problem with his mb sd c4 multiplex. Let's check here.

mb sd c4

Problem Display


sdconnect no connection error   

Reason & Solution

this SDConnect with serial number 101044 is B classes, do not support firmware update online, when it diagnose with newest version xentry diagnostic software, firmware will update automaticly, then the sd connect firmware be locked.

sd c4 with sn 101044

—— Send back for supplier for repair


SDConnect power supplier cut down when the firmware update

Solution—— insert battery for SDConnect, then do the diagnostic processing normally to update the firmware


Pls kindly note:


1. VOBDII.COM online shop mercedes xentry have update to 2017.09 version, if customer need to use our 2017.09 Xentry software working for SDConnect not from us, pls be careful to check the sdconnect serial number firstly.

2. 2017.09 xentry diagnostic software works with HQ SDConnect which serial number is 100925, support firmware update online

3. Any problem caused by customer incorrectly using, we will do not responsible for this problem.

Any other questions about mb sd connect c4 diagnosis and programming, please feel free to contact team.


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Sales: Serena
Skype: autodiagnostickit
Whatsapp: +86-13728823315

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