How to connect BDM100 with Marelli ECU to read data

ECU Chip Tunning

Possible to have a BDM100 programmer read Marelli ECUs?

It should be YES!

In detail…

In case of a Marelli ECU the power distribution cannot be provided by special pads of the BDM port. Use separate wires to connect GND and +12Vcc to the pins of the main connector


(The main connector of the Marelli ECU)

The voltage is provided by a stabilized power supply or by the main connector of the ECU at the cable harness of the car.

Warning!!!! Please always remind, if the open ECU is connected to the cable

harness, it is already connected to the battery!

Please, ensure that the ignition is switched off at beginning!

Before you can start to read out or program a Marelli ECU, you must solder out the zero-ohm resistor witch is next pin19 of the component with SO28 package in the corner of the ECU board


(The location of the zero-ohm resistor witch will be out-soldered.)

There is also another Type of the Marelli MJD- ECU which has another PCB-layout and some other components. There the zero-ohm resistor is placed near the flash- EPROM


(On this Marelli MJD-ECU (with another PCB-design) the resistor is already out-soldered.)

Don’t forget to solder the zero-ohm resistor on its place again when the work with the BDM100 equipment is done.