This thread will be devoted to a thorough explanation of the Mb Star C3 system in depth, over time. Another good reference thread can be found here.

First off, some history and background about the system. The MB STAR C3 is a diagnostic system that is provided by the factory for dealerships and independent repair shops, and is used to interface with the cars’ computers to diagnose systems and pull/reset codes, and even to program certain elements of the systems on more modern cars. The system costs upwards of $20,000 from OBD2TOOL, and is applicable for MBs from model year 1989 and newer.

Of course, cars of model year 1989 only had 2-3 computers in the car; however all successive MBs have had an increasing number of computers, and this is where the MB STAR C3 system really comes into its own — with the newer cars. For the purposes of the cars that are the focus of this forum — the 124.036 E500E — and to a lesser extent the 400E/E420 and the later C126 coupes, the computer setups are rather crude and limited when compared to cars starting with the W210 models, which debuted in model year 1996 in the USA.

What I’m saying is that the MB STAR C3 systems are much more suited and capable, coming into its own, the newer the car that it is used with. However, the good thing is that it is able to fully exploit the built-in computer diagnostics as found in the E500E. It does this using a compatibility mode that emulates the Mercedes-Benz Hand-Held Tester (HHT), which was a diagnostic tool that was used for the 1989 and up cars, commonly until about 2001 when the MB STAR system debuted. The HHT is literally a hand-held unit (it is actually quite a handful) that allows the user to pull and reset codes, provides access to “live” engine data on the M119 and M104 engines (though a larger array of live data on the M119s), and generally pull compete diagnostics of the computer systems.

Mercedes Hand-Held Tester (HHT)

The MB STAR system, when it made its debut, was much more capable because it was PC-based (IBM T30 laptop), but it was also very versatile because it incorporated a HHT emulation mode (for backward compatibility) along with a “multiplexer” intermediate unit between the PC and the car, which allowed the connection of a variety of different diagnostic connection cables, depending on which diagnostic system the car in question happened to use. For the oldest cars (i.e. the C126, early R129 SL models, early W124s and W140s, etc.) a “four-pin” diagnostic cable was provided. For second-generation cars, such as the E500E, 400E/E420, middle and later R129s, middle and later W140s, the familiar “38-pin” plug is provided. There are also OBD-2 interface cables for model year 1996 and later cars, as well as a 14-pin cable for European diagnostic systems. All of these cables allow the combination of the MB STAR with the in-line multiplexer unit to fully interface with any particular car’s computers.

As I said, the MB STAR system debuted around 10-11 years ago, in 2001. Because of its expense, it has been very much “out of reach” of most MB owners and enthusiasts. To pull codes and get information about the car, owners were forced to buy limited testers from companies like Snap-On, Trisco, and others that perhaps allowed one to pull and reset codes, and a couple of solutions provided some limited “live data” where the car allowed it. These systems would typically run from $500 to well over $1,000. The other option was to somehow obtain a used HHT (they are occasionally available via eBay, and are quite expensive) or a used MB STAR system – still a huge expense of multiple thousands of dollars used.

In recent years, Chinese forgers, who excel at making fake copies of everything from Louis Vuitton purses to Guess Jeans to Rolex watches, have set their sights on the MB STAR market (and other automotive diagnostic systems for other marques). This has resulted in a cottage industry whereby one could purchase an MB STAR system for anywhere between $600 and $1,200. Over the past year or so, as Chinese copies of the MB Star C4 system have come onto the market, the prices of the MB STAR C3 system have come down to a typical range of $250-450, depending on the vendor and the items included in the package.

These “clone” systems are easily available on sites like eBay and also Alibaba.com from hundreds of vendors. As with any Chinese copy of anything, quality varies and quite often — but not always — one gets what they pay for. The recent reduction in price of the MB STAR C3 systems has made even relatively good quality systems very very affordable for the DIY mechanic and/or MB enthusiast — providing them with the same diagnostic power as the dealership mechanic (but not the same level of training and knowledge). Typical options that are available with MB STAR C3 systems available on the Internet include: an array of cables; a multiplexer; a hard drive containing the MB STAR software package; and instructions on how to set up the system. The software typically includes: MB Xentry, WIS, EPC, STAR Utilities; EWA net; Star Browser; Star Finder; and a recent MB parts price list (which goes out of date quickly). Quite a number of vendors also provide Internet support, including the ability to remotely control systems over the Internet (with the user’s permission, of course) to diagnose installation and software problems.

There has been precious little information on the Internet about the Chinese MB STAR C3 systems, how they operate, and in general how the system operates. This thread will be a thorough, methodical investigation of how the system works, what it looks like, and how it can be used with the E500E (and by extension, the 400E/E420). It is up to the individual owner as to whether they need or would want such a unit. It would be overkill for many if not most owners. However, there are a number of owners who do want to do their own maintenance and want the tools to help them do this properly. For these owners, purchasing an HHT or MB STAR system may be a good idea.

I will not go into the nuances and details of ordering the system. All that should be said is that one should do their research carefully, and pay attention to the ratings from other buyers as to the honesty of a particular vendor. Most of these vendors are based in Hong Kong or on Mainland China. Quite often they speak decent English and are quite responsive and communicative when inquiries and requests are made. It would be recommended that prospective buyers utilize an escrow service to complete the transaction, so as to maximize honesty and straightforwardness of the transaction from both sides.

Some vendors offer free air-mail shipping via DHL or other international shipper. These packages can arrive in as little as three or four days after a payment goes into escrow and the seller is notified by the escrow company that they have received the cleared payment. Once the package is received by the buyer, they inform the escrow company that the package has been received in good order, and the money is then released to the seller. Pretty seamless, and because of the escrow service — a fairly safe transaction. Certainly better than sending off a Western Union or Credit Card payment to an unknown party in a foreign land.

So, the photos below illustrate what is commonly received with an MB STAR C3 package. It is a 4.5kg (10-lb) box that is nicely packed, and includes all of the items described in the seller’s site. A typical package will include the cables, a USB hard drive (or internal hard drive for an IBM or Dell computer, if specified), a multiplexer box and a packet of adhesive stickers that are placed on the multiplexer and the computer-to-multiplexer cable. The box is unpacked and the contents are checked against the web site’s description to ensure that all contents were included. Some sellers also sell individual pieces of the sets, if they are ever needed.

Next, after the contents of the package are ascertained to be correct, the recipient should install the software on a computer. It is HIGHLY advisable that a standalone, separate laptop computer be used for this, seeing as it will be used in a garage (next to the car) environment. For versatility (and because most people don’t own the specific IBM and Dell laptop models that are needed for the internal drives) it is advisable that the buyer specify the external USB hard drive model of the MB STAR C3. This way the hard drive can be plugged into any qualified laptop and used.

Requirements for a laptop that can be used with the MB STAR C3 system are generally as follows:

Must have a SERIAL port
Must have a processor frequency rating of 1.8 GHz or higher
Must have at least 1 GB of RAM; more is highly desirable
Must have a USB 2.0-compatible port
Must be running Microsoft Windows XP

It is best to just purchase a used laptop via eBay or Craigslist that meets these specifications, and use this computer SOLELY as a DEDICATED computer for the MB STAR installation. It can be kept in the garage and used for these purposes. It really doesn’t even have to be connected to the Internet. One can also put the laptop on a dedicated cart, which allows the computer, cables and a printer (if desired) to be rolled around the workshop/garage next to specific cars. Although the cables are quite long, it’s nice to have the computer next to the engine when using it.