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OBD2 PIDs of BMW N-series brake pressure

Posted: Sun May 23, 2021 4:07 pm
by tonytkdk
I found this BMW N-ser PIDs.
https://docs.google.com/spreadsheets/d/ ... sp=sharing

Brake negative pressure Bremsunterdruck 101069 1 0 bar
Linear brake negative pressure Bremsunterdruck linearisierter Sensorwert 101068 1 0 bar
Brake negative pressure raw voltage value of the sensor Bremsunterdruck Spannungsrohwert des Sensors 10106A 0,2 0 mV

May I know how to add these into Laptimer's custom PIDs?

Thanks // Hugo

Re: OBD2 PIDs of BMW N-series brake pressure

Posted: Sun May 23, 2021 4:49 pm
by Harry
Interesting, but I can't provide an out of the box solution here.

Here are some guesses and recommendations.
  • I'd search / investigate the source of the sheet, you may find some hints there on how to interpret it
  • The starting point to make this work with LapTimer will not be the app. Instead, I'd use a terminal application on a PC/Mac and connect to an ELM327 based OBD adapter. Following instructions in https://www.elmelectronics.com/wp-conte ... M327DS.pdf, I'd start to check communication to the adapter, something like entering "ATZ<CR>".
  • Interpreting "2C" as a kind of OBD mode, I'd enter "2C 101069<CR>" now and check if the adapter is coming back with an answer.
  • Looking into custom PIDs for other brands, I know they usually require us to address a specific ECU instead of broadcasting. So you may need to set a proper header.
Especially the last two items are really a wild guess and may proof I have no idea of OBD / CAN mappings. :-) LapTimer communicates one level higher, so it is beyond what I'm working with usually.

Maybe some other user with deeper insights can help?

- Harry