How to Read Fiat MJD8F by Foxflash Successfully?


Is it possible to read Fiat Marelli MJD 8F by Foxflash ECU Programmer? via OBD or bench?

Here is the answer:

Yes. You can read and write with foxflash via OBD or Jtag mode.

If you use bench mode, it can read ID but will fail to read data and appear “error Boot1”.

The reason is that Foxflash can read and write Marelli MJD8F full system. It will read the whole backup. No need to connect BENCH BOX when reading this ECU.

Foxflash read/write Fiat MJD 8F in Jtag mode:

MARELLI MJD 8F, 8S, 8DS — FIAT, Suzuki [Diesel]

Connect the multifunction cable as follows:

Pin 3, Pin 50, Pin 88: +12V (Red)

Pin 2: GND (Black)

Solder the rainbow flat cable on the PCB:

To read and write use the following driver:




-> MPC 55xx

Foxflash read/write Fiat MJD 8F via OBD:

Make sure the power voltage is enough.

If the voltage is low, you can read/ write/checksum OK with foxflash ECU Chip Tuning Tool, but may appear “Error Inject”.

In OBD you need minimum of 13V try 3 or 4 times however reading is minimum 1h!

It is reading marelli. Foxflash software does not upload injector codes file when finishing writing. Gotta get the injector codes back.

You need to do code injectors read with a scan tool when you work with Marelli via OBD every time.

Flex just deletes the injectors code even if you just make a read by OBD.

The safest way is that you’d better use an Autel scanner or similar tool and take note of the lettering code of the injectors. Then just write them back with an Autel or similar scan tool after the mod.

Even if we backup the injectors code with flex, you can just make it to write them back correctly.

Somehow, the reading of that memory position does not work well.