Please bear with me, as I'm a bit of a noob when it comes to ODB2 & CAN Bus matters; last time I played in this neighborhood you popped out the ROM and read it in a ROM reader, so that'll give you a little context
In any event, I'm wondering if the RR community has a list of Range Rover-specific PIDs. I know the lower range (let's say coolant temperature) are standard, but the vast majority are not. Let's say that I wanted to build a little ATMEL device to watch for the ignition starting and in response send the command to turn on the foglights. I'd start by mocking this up on a laptop with an ODB2->USB (or serial) device from one of the vendors.
But how on earth would I ever figure out what PIDs coming across the bus would tell me that the engine is starting (ok, I could use oil pressure I suppose, and that's standard), let along how to send a command to the Body ECU or whatever unit controls the foglights?
I would imagine that just watching the stream of command and hoping I spot the right one when I manually turn on the foglights would be hopeless, since there's so much other chatter on the bus.
Can someone give me a really brief braindump introduction on how to monitor for, interpret, and send custom PIDs like that? I really need a hobby, and this sounds like a fun one if I can get started