0x5A=90For what it's worth, on mine 0x21 0x5c returned:
7E9 07 61 5C 0D D0 00 50 5A
That was with the engine off, however.
I don't think that is correct. I don't have access to a JK but other vehicles I have worked with that have the old gateway architecture pass CAN-C straight through to the DLC. If CAN-D were truly a separate network then it would require a termination resistor in whatever plugs into the DLC and that is a no-no according to SAE specs. I suspect if you have the ability to monitor broadcast messages, you will see there tons of messages coming through the DLC. There is no reason to do that unless the DLC is directly connected to CAN-C.When you're talking to the CAN-D bus (the diagnostic bus via the OBD-II port), you are not able to electrically communicate directly with the CAN-C or CAN-interior busses. The TIPM module acts as an electrical gateway between CAN-D and the other two.
Agreed but there should be 120's on each end of the bus. If the TIPM creates a separate bus then I would think there would be just one termination resistor there. At that point you would still need another, I don't know where that would be. Maybe they create a properly terminated bus completely internal to the TIPM where the DLC/tester is just a node. Either way this is the first gateway vehicle I've heard of that behaves like that.Remember, too, that the DLC is effectively a node in the middle of the CAN-D bus, so it doesn't need termination there. The TIPM is the termination point of the bus, internally.