Re: EF Falcon start issue
Just under the screw at each corner of the dash near the windscreen (next to those speaker grills) and slide the panel off (towards the rear of the car) then you see a bolt near the windscreen at the centre (almost directly below the rear vision mirror) this will have 2 earth wires under it with ring terminals; ensure this bolt is tight. You cam use your multimeter to check that the relay sockets in the fuse box are earthed but this is not a foolproof way as a loose earth bolt will mean you have an earth but a very poor and intermittent earth.
To get the Smartlock codes turn the key to the run (final) position and count the flashes of the Smartlock warning light (0, 2,3, 4, 5, 6 or 8 flashes). if you get a code it's likely the BEM has a dry joint.