You only need to connect all ground together with your power ground.

Regarding the switch you cannot switch between branch without refactoring the code to merge both branch in one.

Nice ! Ah yeah, that could be very nice to now that !

Yes it is a very complicated calculation, even worth now with de-pollution systems. the misefire could be coming from a lot of things ... That's why it is nice to now of the software works when you want to diagnose an issue !

Very nice project! would it be possible to share the SBL for the DENSO ? I did a similar thing on old Fenix 1B (Renault 2L Turbo ECU that I put into a Clio RSi with a mercedes compressor added to the engine) that was based on 68HC12 MCU, I finally was able to rebuild on paper the complete formula ...

Oh ... at least 2 month working on it by night when my child is sleeping... That's also why I'm sharing it, making win time to people who need it. I understand ! Have you made a SBL for the SH7055 ?

No, from what I suppose, B4 command is only working on High speed CAN devices, for example CEM 0x50, CEM on low speed CAN at 0x40 isn't working with B4 command, this is the same for DIM. That's my finding. My SBL is implementing the B4 command once it is loaded and running

Have you tried my tool ? I was able to dump the DIM with it but yes, without the B4 command while uploading the SBL, after the SBL is running, the checksum are verified.

Ok, my SBL will not work for that MCU, don't even try as it can have unknown effect on the CEM, in the better case just reboot it, in the worth case burn it by setting a wrong configuration on the MCU. I don't know the register architecture and opcode on M30855F.

Regarding the xiaofei204716's ...

I don't have a P2 CEM so I don't know what MCU is inside but if it is a 9S12, chances are high for this to work with maybe some modifications.

Is it a 9S12 MCU inside ? If yes you can edit my SBL to do this job