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· Registered
C350e / 2017 and SLK 200 / 1999
19 Posts
Discussion Starter · #1 ·
(This is cross-posting from SLK World which I publish here in the hope that it will be useful to other people as well)

I bought a multiplexer and cables (38-pin, OBDII and analogue) directly from OBD Factory in China. My contact at OBD Factory was very service-minded and dispatched my stuff as soon as I had made the payment through Paypal. Delivery was via courier and took just a few days. All in all (purchase, handling charge, shipping, customs), I spent less than $90. I am very happy with the way OBD Factory handled my purchase, no complaints whatsoever.

OBD Factory also have a cheaper product without the multiplexer but since different subsystems in the car deliver their data on different pins of the 38-pin connector, I thought it was a good idea to have a multiplexer that selects the right pin automatically rather than me having to move a wire manually between pins.

Attached with the package was also a mini-CD with the Carsoft MB 7.4 software. As it turned out, this was a pirated copy that contained a virus or trojan that my anti-virus software warned against. Although it was easy to remove, I managed to find a virus free MB 7.4 'elsewhere' which I installed on an old laptop running Windows 2000. Installing the software was a hassle but as long as you read the instructions carefully you should be OK. I had read that people have had problems using the software on newer machines that lack a necessary RS-232 serial port. Apparently USB-to-RS-232 adapters are not good enough, you have to have a PC with the real deal i.e., a built-in RS-232 port. Unfortunately you don't find them on newer machines so you have to find an old one. I got my 10-year old Dell Latitude CPx junk laptop for free from a friend of a friend who was just about to throw it away. It is perfect for a garage computer since you cannot use it for anything else anyway.

The Carsoft software, at least my version MB 7.4, looks its age to say the least. It is quite apparent that the guys who designed it know cars better than software engineering (I am a software engineer myself so I think I understand these things). The user interface is primitive and there is no useful online help or anything, you are more or less on your own when it comes to learning how to use the program. Luckily it's not difficult:

First you have to tell the program which type of interface to use (OBD or 38-pin). Then you proceed to the Digital Test menu and start by selecting Complete Diagnosis. This test scans a number of subsystems (26 in my case) and prints a screen with the status: OK, ERROR or no response. I was surprised to see that most of my subsystems did not respond but after further investigation I concluded that most of the unreachable subsystems are not installed in my car. It is documented somewhere in the software that in case of unreachable components you may have to turn off and turn on the ignition several times to get a response. I haven't really tried that so I don't know how it works. The systems that gave me a response were:

ME (petrol engine control unit)
ABS (anti block system)
BAS (brake assist)
Instrument cluster
AIRCO (air condition)
PSE (pneumatic system)
VD (vario roof)

Most of these systems gave me ERROR, indicating stored error codes. To read the errors you have to test the subsystems individually, which will produce a list of error codes and (maybe) a textual description of the failing component and error. For instance, this is what I got from VD:

B1490 Pump relays
B12670 Trunk lid open and trunk lid closed limit switch activated simultaneously
B1272 Hardtop closed switch activated while hardtop open switch is not activated
B1279 hardtop (locked) switch (left or right)

After this, you can go to another menu to erase the codes (after all, they can have been there for ages and it's impossible to know whether they are still relevant). If you then use the car, error codes of faulty systems should re-appear the next time you run the test.

There is also a menu that produces live data when the engine is running. Most of these functions seemed to do their job, although I can't claim I understand how to use the data. If you understand the engine better than I do, it is probably useful. I don't know whether the functions which didn't seem to work are at all applicable to my car, the software is meant to handle many different Mercedes models.

The system does not 'exercise' the roof, it only reads stored error codes. The only system that was noticebly 'exercised' in my case was the air conditioning system, which made clicks and noises during the test cycle. I guess this depends on how the subsystem was designed to respond to test inquiries. The subsystems are all delivered by different manufacturers (Hella, Bosch, ...) which is shown in the test results.

To summarise, my Carsoft version is quite primitive but it seems to do most parts of its job decently well. I definitely think it was worth $90 to get the connection kit, as the mulitplexer and the cables should be useful for other cars as well, as long as you have the appropriate software.

If other people who read this have experience from Carsoft, please comment, particularly if you have managed to get data from other subsystems than the ones I listed above!

· Registered
Two 1998 SLK230s, 2003 SLK230 SE, 2002 ML320
921 Posts
Same experience. You can use a PMCIA or Cardbus COM adapter if your laptop doesn't have a built in COM port. There is already a very long thread on this topic. Thanks for sharing your experience.
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