(Solved) Kess and Ktag error reading Magneti Marelli

Post starts with Kess and Ktag error reading Magneti Marelli description, then provide solutions.


Kess and Ktag error reading Magneti Marelli.

I just bought KESS V2 V5.017 and Ktag K V7.020 Master Clone from a vendor recommended by a friend. Both are reformed by the seller to ensure proper operation. At all times the vendor has been very serious and the friend who recommended it to me assured me that it was trustworthy

When I got both interfaces, the vendor made his installation.

All very well up there, but when I try to read the first 2 control units (Magneti Marelli 4MV and 4BV) which I have urgency to read, in none of the cases was it possible to read

I put the details of the procedure below to see where you think the problem may be:

Procedure with Magneti Marelli 4MV Skoda fabia 1.4 Engine: BBY

Tool used Kess V2 using OBD2

This first reading was done in bank, proceeded with the pin-out correctly

The first error I receive is:

Warning, unknown ECU. For a correct procedure you must send log files and Reading to the technical support. Proceed anyway?

When giving OK, the program managed to read me the HW information

HW: MARELLI Boot 4MV r06

Upg. SW 036906034FD 4823


Then the next poster is:

Error while transferring data in Reading


Modify the speed of reading with each one of the variants that the Kess brings, but all in vain


Then connect directly the Kess to the OBD2 port of my car (Skoda fabia 1.4 BBY) that has an ECU equal to the aforementioned and the results were the same.

– When I tested on my car do not use external charger (The voltage was a little below 12V)

Do you think the solution is to increase and stabilize the voltage through an external charger?

Is the correct voltage just as important for a reading?


Procedure with Magneti Marelli 4BV VW Gol 1.0 Engine: AZN

Tool used KTag using Boot-Mode


In this particular case I decided first to check that the control unit worked properly, for this mount the ECU in the bank, with its correct pin-out but without connecting the gray cable boot mode, and proceeded with a reading of the ECU supporting me in the Vag-Com. Then the vag com could read the ecu, see fault codes, etc.


Already the possibility that the ECU did not work was ruled out.


Then I removed it from the OBD2 adapter and made the connection as the Ktag indicated, connecting the gray cable in its correct boot mode, etc. (I am sure that all the connections were made correctly)

When I give it to read, it gives me the following error:


Communication error with the ECU: control all connections; if the problem persists, send log file to the assistance


In this case as a power source use the original transformer that brings the ktag that also does not reach 12v.


Could this also be the cause?

I can connect directly to the Ktag in the power outlet that he brings, a 13-14V source, or it is advisable to connect directly from the external source to the control unit without going through the Ktag.

Can the ktag break if instead of using the original transformer that he brings, I connect an external source of 13-14V, 2Amp?

I have doubts too, it is correct that when the ktag with its original transformer connected if the voltage is measured in the red wires (+) is 0, but when I read it the ecu in the ksuite if it gives the 12V. Is this operation normal?


Given all these problems, contact the seller and he told me the following:

Magneti Marelli is the worst type of ECU are not reliable and can not always be read.


What do you think?

I see that both control units are on the kess list as the ktag, so they should be able to be read without any problem, I think.

Or are you in agreement with this and it is true that many times they give problem and can not be read even if they are on the list of ecu supported by alien-tech


The seller also told me to try other cars to see that everything was going to work properly, but to be honest I am afraid that trying to read a control unit of a car is going to block and stop stepping paper and more even being a beginner in this subject.

Is there a risk that the ECU can be blocked just by trying to read it?


Friends the truth that I have the head done a mess with all this and I do not know how to proceed in the future. I would like you to give me your opinions and comments to see what you think of all this. (lágrimas)(lágrimas)(lágrimas)



  1. You need to open ecu take metal cover off eeprom(soic8)and bridge pins 4 and 5 with a wire. then you can read with fgtech via kline.


  1. I could read the Magneti Marelli 4MV and 4BV ECU, with Kess V2 using OBD. I also read a Bosch Med 7.5.10 with the Ktag. I think the success was in maintaining a stable voltage with a regulated source.

I am very happy with the reading.