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Mercedes STAR Diagnosis and DAS

Revision 1

by llandowtuninguk@gmail.com
Add curated starter reference (2026-11-10-mercedes-diagnostics)

This is a historical revision. Read the current page or return to its history.

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STAR, DAS and the rest of the system

STAR Diagnosis, often called SDS or Mercedes Star, describes a family of Mercedes-Benz workshop diagnostic systems: a diagnosis computer, software, vehicle interface and appropriate cables. DAS here means Diagnosis Assistance System, the diagnostic application used for many older Mercedes vehicle and control-unit generations. In other documents DAS can instead mean the vehicle's drive authorisation system; read the context.

Earlier STAR installations also included HHT-WIN for legacy functions. The later XENTRY environment can open DAS for supported older model series. Mercedes confirms this integration for the limited scope of XENTRY Pass Thru EU. Selection depends on the model and system, not a universal changeover date.

Workshop functions

Depending on the vehicle, release and authorisation, the environment provides a quick test, control-unit identification, fault-memory reading and clearing, actual values, guided tests, actuations and control-unit commissioning. Coding, adaptations and programming are distinct operations: a tester that can read a fault does not necessarily have the data, interface or rights required to replace or update the controller.

WIS is the workshop information system containing repair instructions and reference data; it complements diagnosis rather than replacing the diagnostic application. Match the procedure to the VIN, model, engine, control unit and market.

Historical example: SCN

A 2007 Mercedes service document for models 639 and 906 describes obtaining Software Calibration Number (SCN) coding data through the SDflash central service and then writing the coding through DAS. It also documents a historical alternative: request the data by fax and receive coding information by reply fax or on an SCN repair CD. That was a manufacturer-supported process for the specified applications; it does not establish that the fax or CD service is available today, or that every later SCN operation can be done offline.

SCN identifies a software and coding configuration in the documented emissions-related context. It is not the same thing as a fault code, a complete ECU flash file or a general-purpose offline unlock. See legacy networks and ECU coding for the earlier HHT and resistor-plug examples.

Using a system today

Confirm which software release, diagnostic computer, multiplexer, vehicle cable and online rights the intended vehicle and job require. Older installation media may not include newer hardware support, and current software or services may not reproduce every historical feature. Record original identification, fault data and available coding before replacement; follow the manufacturer procedure and use stable supported vehicle power for programming.

Sources

Curated reference notes. Applicability follows the cited sources; hardware testing by this wiki is not implied.