Cambridge Avionics has a device called CAV13 (http://www.cambridgeoperations.com/CAV13_Manual_3_0.pdf) that reports ECU status information from the CANbus, and one error is called the "interlane keepalive discrete signal failure", and it is only present on 915iS engines, distinct from the "interlane communication failure" present on both. I assume this status is triggered if an interlane watchdog times out. I know what interlane communication is and I know what a keepalive is, and I can guess why it's necessary to use discrete keepalives (to distinguish between a lack of interlane status information and lack of a functional interlane) but why do only 915iS engines report this status and not 912iS? Do 912iS engines not have an interlane keepalive or do they report interlane keepalive time out as an interlane comm failure or do they just not report if the connection times out (I suppose that's what it means by failure)?
Do I perhaps have to take an iRMT course like "9 Series Injected Diagnostic Course" to find out the answer?
