Odp: Odp: Motronic 2.4 (BMW motorcycles)

[Marek Skrzypiec]

Hi Nils
Sorry that you've  had to wait for my reply so long ,but  I'm very busy and
sometimes I haven't time for nothing.
First to comunicate with ECM you MUST have some scantool.It could be
stand-alone device like Bosch KTS ,Sykes-Picavant , DIY and etc , or you can
'talk' with ECM by PC using  a special inteface.That interface must ensure:
two lines - L unidirectional (PC -> ECM ), K bidirectional (PC <-> ECM);
signal levels : logic 1- 12v, logic 0 -0V , both with tolerance +/- 20%;
serial transmision with the parameters like wrote down above;
and of course the software.Mine I'm writing only in polish.
That wil be enougth to DIY scantool.
If have you any question , you can ask me .

Marek
elemark at friko4.onet.pl


>Marek Skrzypiec wrote:
>>
>> Hi
>> Bosch usually use their own transmision protocol , which is accorded with
>> standart ISO 9141-1.
>> Usually transmision is bidirectional via line named -K , but sometimes
are
>> used two lines :
>> 1)bidirectional K for transmiting datas
>> 2)unidirectional L only for begining .
>> In this case I think that it is one wire transmision.
>> To begin the protocol you must send byte $10 to ECM with baud rate
>> 5baud(1start,7data,1oddparity,1stop).
>> After that you should recive six bytes , with  value $55 at begining -
baud
>> rate is 4800baud(1start,7data,1oddparity,1stop but for first byte $55
>> :1start,7data,1parity,1stop).
>> Characteristic of ISO code is :
>> 1byte - synchronization -always $55
>> 2,3byte - family of ECM
>> 4,5byte - key word
>> 6byte -check sum.
>> When you will send !3byte (inverted) .At now transmision perform block by
>> block  with baud rate 4800baud(1s,8d,1s).Characteristic of block is :
>> 1byte-dimension 31 bytes
>> 2byte-title
>> 0<byte<29-informations
>> 1byte-check sum.
>> I wish you succesful
>> Marek
>
>G'day Marek
>
>Thanks for the reply. Unfortunatly whilst I have a good practical
>knowledgeof EFI, I do not have your expertise with digital systems or of.
>programming. With this in mind could you spare the time to explain in a
>little more detail the steps you described - keeping it as simple as
>possible please.
>
>I agree it is a single line bi-directional transfer of data but in
>practice what do we have to do to get the codes.
>
>Hope you can help
>
>Cheers
>Nils
>
>
>