Kein Wunder, OBD II ist seit 1996 !! verbindlich für in den USA hergestellte Fahrzeuge vorgeschrieben. Europa hat dann erst 2001 nachgezogen.
Ist auch kein "kleines Bus System", sondern der J1850 Bus, der damalige Industriestandard, genauso wie heutzutage der CAN Bus.
SAE J1850 VPW (variable pulse width — 10.4 kbit/s, standard of General Motors)
Bus idles low
High voltage is +7 V
Decision point is +3.5 V
Message length is restricted to 12 bytes, including CRC
Employs CSMA/NDA
ISO 15765 CAN (250 kbit/s or 500 kbit/s). The CAN protocol was developed by Bosch for automotive and industrial control. Unlike other OBD protocols, variants are widely used outside of the automotive industry. While it did not meet the OBD-II requirements for U.S. vehicles prior to 2003, as of 2008 all vehicles sold in the US are required to implement CAN as one of their signaling protocols.
pin 6: CAN High
pin 14: CAN Low
CANH signal voltage level: 3.5V (min/max 2.75 to 4.50)
CANL signal voltage level: 1.5V (min/max 0.5 to 2.25)
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'First shalt thou take out the Holy Pin. Then, shalt thou count to three. No more. No less. Three shalt be the number thou shalt count, and the number of the counting shall be three."