Hello,

I have this also posted in the GS forum, but as it could be across the Lexus range I am asking here too

I am planning to make my own OBD-II reader as part of my carPC using the ELM327 chip ( www.elmelectronics.com ). There are a few different OBD-II formats .

J1850 VPW--The connector should have metallic contacts in pins 2, 4, 5, and 16, but not 10.
ISO 9141-2--The connector should have metallic contacts in pins 4, 5, 7, 15, and 16.
J1850 PWM--The connector should have metallic contacts in pins 2, 4, 5, 10, and 16.

The full pin-outs of the connector is:
Pin 1 - Blank
Pin 2 - J1850 Bus+
Pin 3 - Reserved
Pin 4 - Chassis Ground
Pin 5 - Signal Ground
Pin 6 - CAN High (J-2284)
Pin 7 - ISO 9141-2 K Line
Pin 8 - Reserved
Pin 9 - Reserved
Pin 10 - J1850 Bus-
Pin 11 - Reserved
Pin 12 - Reserved
Pin 13 - Reserved
Pin 14 - CAN Low (J-2284)
Pin 15 - ISO 9141-2 L Line
Pin 16 - Battery Power

My 98 GS300 has pins 4,7,13,14 and 16! so it is a part ISO and a part CAN, does anybody know what OBD sub-protocol it is??

Thanks