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BMW Brake pressure sensors (E46 & others)

Posted: Fri Apr 01, 2016 1:55 pm
by smallspeed
Has anyone ever "mapped" a brake pressure sensor from the e46 m3 or similar? I believe these pressure sensors are used in all of the e46 era cars with DSC / ABS systems

I already have two in my mk60 ABS system (front/rear) but these do not output any data via CAN - I think they do output on some cars though, and they should be the same sensors..

I've managed to pick-up a couple of sensors cheap, and was planning on using them as analogue pressure sensors for RCP2, however am not sure what the output will be or what that will relate to (ie 0.5v - 4.5v equalling 0-250 bar or whatever). If I can't figure it out I'll keep them as spares and just use the brake light switch and TPS to indicate "coasting"

Hope someone can help

Posted: Wed Nov 07, 2018 5:37 pm
by smallspeed
Circling back on this..
From what I can work out, the sensors read from 0.5-4.5v with a max 150bar
The signal is linear, so..

P = (V-0.5)*37.5

..or..

3.75bar per 0.1v

..or..

0.5v = 0bar
4.5v = 150bar

..depending how you’re programming it in
I don’t believe these poll over CAN so they’re purely available as an analogue signal if required
If I remembered my pins the correct way around..

PIN 1 - GND
PIN 2 - Signal
PIN 3 - +5v

Posted: Sat Nov 24, 2018 11:01 pm
by brentp
Hi, thanks for sharing this information. Are these the specs for the OEM sensor uses in the E46? They seem very similar to the standard 0.5 - 4.5 mapping you see with typical aftermarket sensors as well.