MS42 Pinout (Siemens DME Bench Pinout)

Bench pinout for the Siemens MS42 DME. Use the pins below to power the DME and talk to it over K-Line when reading or flashing on the bench. All bench connections are on the 9-pin power connector, the first connector on the left (circled in green).

MS42 DME bench pinout diagram showing 12V pins 1, 2, 7, 8, 9, ground pins 5, 6 and K-Line pin 3
MS42 DME bench pinout – 9-pin power connector highlighted.

MS42 bench pins

FunctionMS42 pin(s)
+12 V1, 2, 7, 8, 9
Ground5, 6
K-Line3

Which cars use the MS42 DME?

The Siemens MS42 DME is used on the M52TU six-cylinder in late-1990s-2000s E46 and E39 BMWs. Not sure what you have? Use our ECU identification guide.

How to bench flash an MS42

  1. Connect a stable 12 V supply to DME pins 1, 2, 7, 8 and 9, and to the KDCAN cable’s 12 V pin (OBD pin 16).
  2. Connect ground to DME pins 5 and 6, and to the KDCAN cable’s ground (OBD pins 4 and 5).
  3. Connect the KDCAN cable’s K-Line (OBD pin 7) to DME pin 3.
  4. Open your K-Line software and connect to the DME as you would over OBD.

The KDCAN cable needs 12 V and a ground shared with the DME to communicate, just like it gets from the OBD port in the car. Tip: double-check every connection with a multimeter before powering up, and use a power supply rather than a weak battery charger.

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