Hi mate, when you disconnected the negative battery cable, the
bem & smartshield may have stopped communicating unfortunately. Do a AFF search, punch in "au smartshield problem" & see what comes up.
I have a AU1, not familiar with AU2, so hopefully other members with experience on this matter will chime in soon, also while your at it, check your inlet manifold bolts are tight & secure, good luck!
cheers, Maka