Brake Pressure Offset/Length

Discussions on CAN mapping for ECUs, sensors, PDMs, and more.
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Joined: Sat Oct 16, 2021 11:18 pm

Brake Pressure Offset/Length

Post by MattyYagr »

I'm working on brake pressure for my Mk7 Golf R and believe I've located the channel but I'm struggling with the offset and length. Offset 2 directly correlates with my pedal inputs, the value at zero pedal is 100 and cycles up to 255 as I increase then cycles back to zero and up again as I continue increasing. At the exact moment it's resetting Offset 3 shows a value of 4 (up from zero) and the next time Offset 2 hits 255 Offset 3 shows a value of 5 suggesting maybe that it's a multiplier? I tried plugging in an Offset of 2 with a length of 2 in the channel and it's sort of working but not exact. The value on the gauge starts off normal then suddenly jumps very high and starts to act normal from there as I continue to increase brake pressure. I'm sure I have the offset/length incorrect, or perhaps the formula is wrong? I can provide the spreadsheet if anyone thinks they can help. None of the other values on that channel seem to match up with the pedal inputs.

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Re: Brake Pressure Offset/Length

Post by brentp »

If it is cycling 255->0 and over again, then it sounds like the low byte of a 16 bit value. Try treating it as a 16 byte value and choose either big or little endian for the adjacent high byte.
Brent Picasso
CEO and Founder, Autosport Labs
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