GM HSLAN specifications

[george]

I am designing a module to Read only the high speed can bus of a gm vehicle. I know the data I am trying to read using a scan tool and software. The scan software says the data bus is running at 500kbps. I am running the standard CCS PIC 18 can bus software in mode 1. The baud rate was calculated by using a software program and the appropriate registers updated. I am able to make two can modules talk together at 500kbps, however when I attach reader to vehicle, it is unable to read the gm bus.

Any Ideas?

Thanks Geo