[arpad_m]

I'm not sure about your interpretation, because the diagram indicates open ground by default on 45-48 (bank 1) and 49-52 (bank 0) and an activation switch inside the ECM.

The ECM has several grounds indeed, but they are not specific to injector banks, let alone individual injectors, so that can be ruled out.

How would catch injector pulses with anything less than an oscilloscope when these only last a few milliseconds even at WOT and in fact barely longer than 1ms at idle? I'm no mechanic, but since each injector pulse will only take a small percentage of total elapsed time, I'd think one needs a proper tool to see if the ECM actually sent the signal to fire an injector, you can't observe these fast and short voltage changes or power bursts with normal garage tools.