Ok, here is the result, straight from my garage :) The signal below was taken from pin 14 of the blue ISO connector, with a connects2 VRNX001 interface hooked up instead of the stock CDC.Quote:
Originally Posted by Vicne
Horizontal: 2ms/div -- Vertical: 5V/div
Horizontal: 0.2ms/div -- Vertical: 5V/div
Ground level was set at the vertical center. As you can see, low signal level is not entirely 0V, but definitely not 3V. It turned out to be less than 1V. High level is pretty much 12V, as could be expected. Data at pin 14 appears about once every second. Pin 13 seems idle, unless keys are pressed on the HU or stalk. Low and high levels at pin 13 are equal to those on pin 14, i.e. 1V/12V
My suggestion to you to get rid of the annoying 3V bias would be a comparator like a simple LM324 with a threshold set at around 6V.