This might be a dumb question, but there's only one ABS pump on the bike correct? So if you activate the rear ABS then you are cycling the pump. Is it necessary to activate the front ABS as well? Obviously that will test your valves etc. in the front end, but wouldn't make any difference for the pump would it?
Correct - just one pump. As we know there are 2 types to ABS units - linked and non-linked. The solenoids and valve are activated each time the bike is started and ridden a short distance then the ABS light goes off - it's supposed to stay ON if a fault is detected. The pump is not activated during the initial self-test process.
Smitty's problem, mine and a relatively small but slowly growing number of other owners of the early (non-linked & separate circuit system) bike find that the ABS light goes OFF but the rear brake will fail to apply upon first and subsequent applications - no rear brake whatsoever, just a solid pedal that cannot be depressed.
The linked system seems to be fault free in this regard from what I've seen and read.
The behaviour of the ABS system is different between the linked and non-linked systems while the
linked system will exhibit different behaviour dependent upon the type of surface each tyre is in contact with - because the front & rear are linked.

MOB, gen 1 faults are retained within the ABS ECU memory even when it's removed from the bike and can only be deleted by following the prescribed procedure when powered up. If his ABS light never came on it never recorded a fault.
As the KDS3 can be connected to the ABS unit it may be a good move to have the faulty unit checked that way before disassembly to see if KDS3 detects something that the self-test system does not - just a thought.
FWIW, and as I'm sure you already know, the gen 2 unit is a little more complex electrically due to TC and consequent connections to the bike's ECU and has a different fault display/retrieval/delete.
Finally, there is a similar discussion happening on 'the other' forum which I and others here are watching or posting to.
