SD Connect C4 – what you can & cannot do?

car diagnostic tool

With SD connect C4 on Mercedes, what can you do & what can’t you do? Here you go.


What can you do? 

So what’s possible with a SD Connect C4 kit. You would see by now, that the software will provide you with an astonishing array of information to come to terms with. I won’t say the possibilities are endless, but they are certainly vast.

From a learning perspective – you have everything you could wish for. Theoretically you could be satisfied with a copy of the WIS alone, since that serves as probably the most comprehensive learning tool for the vehicle.

From a diagnostics perspective – you will be satisfied with multiplexer and XENTRY/DAS. The range of tests which you can run and actuations you can trigger will let you fully examine each part of the car. You can generate detailed test reports, seeing when faults occurred exactly in each of the computer modules – and believe me, there are a lot of those. The W205 has upwards of 50 control units with each of those capable of logging and tracing out detailed errors and fault finding.

From a configuration (Adaptations) aspect, there are some minor things (often referred to as ‘Teach-in processes’) possible (e.g. Airmatic level calibration) but it isn’t a treasure trove for those willing to tinker with the vehicle (see next topic). One aspect I also didn’t delve into further within this review is that you can also configure and update module software from within XENTRY (a process called SCN Coding) which is only available online for the W205 (i.e. you need an authorized Mercedes user account to do so). There are Chinese vendors who will sell you a ‘session’ for online SCN, but it can get expensive quite quickly. In reality it is not something you would do other than to perform major update tasks (e.g. after replacing an ECU or other module) if the car was outside of warranty.

What can’t you do?

If you’re looking at ways to change significant default behaviors in the W205 vehicle systems (e.g. allow Video in motion, disable your start-stop, change variant codes etc. ) then you will probably be disappointed. MB has gone to some length to ensure that certain changes are extremely difficult to achieve. Offline coding was to a large extend abandoned with the W204 to guard against incorrect configurations. That’s not to say there isn’t a way, rather that these lock-downs are probably in place to avoid introducing configuration errors inadvertently during maintenance or by amateurs who don’t know what they’re doing.

There are more extensive changes possible with a software product called Vediamo, which is a factory tool used to perform complex black magic best not brought up in this review (makes sign of the cross; heck I’m not even religious!). Regardless of your skills in Vediamo, my research and impression leads me to believe that most changes also require Online SCN coding, which leaves you with little room to achieve known outcomes. Given that people do like to tinker or hack technology I’m sure this topic will become somewhat irrelevant in the future. Yes, people will find a way – whether that’s a good or a bad thing, I shall not judge.


So.. your glass of wine is empty and you’re wondering “What the the heck did I just read that for!). If you were to ask me again “Is it worth purchasing a kit like this for your car?” I would offer you an unreserved “Yes” – although with a disclaimer.

If you are the type of person who shows an interested in learning the in’s and out’s of your vehicle, then I can’t think of a better way than to own one of these setups. There is such a vast amount of content and useful reference material that it serves as a valuable library to learn more. Whether your goal is to perform self-maintenance, troubleshoot issues or simply to see for yourself what is going on inside of your vehicle, then this is without a doubt the toolset which allows you to do so.

If on the other hand you would prefer to say “here you go – fix it”, or perhaps rather be ‘told what’s wrong’ with your car, rather than ‘know what’s wrong’, perhaps you’re better off saving your dollars for other toys.

The W205 is undoubtedly a computerized marvel on wheels. Many of the systems and technical aspects of the car are completely obfuscated from the regular plebs like us. A diagnostic kit such as this certainly allows you to delve under the covers and go as deep as your curiosity wants.