For some reason my Mach3 system has started failing on the Auto Tool Zero script.
Its behavior is normal to begin with. It travels down to the probe at reduced sped. Stops when it touches the probe unit. This is where it goes wrong.
The Z value is around -35.00 (as is the Machine Co-ord). The value returned for the GetVar(2002) is very different. Say 1.5. So when the probe should retract 1-2mm. It actually travels up to the +1 position (+36mm)
This used to work well. I have also used various other scripts. And ALL produce the same issues.
Any guidance would be really appreciated.

Did anything change in your system?
Are you using a motion controller? If so, which one. Many do not support GetVar() properly.
If nothing has changed, try replacing your .xml file with a backup.

Yes, there have been a few changes recently. I was thinking along the same lines.
All of the Motors have been upgraded from 2A versions to 4A (Nema 23).
And i have added a Remote Handset.

Having thought about this. My plan is to revert to a known good point. And see if things improve!
In summary. The Motor upgrade included changes to some DIP settings. And the remote handset another plug-in.

Thanks for your reply. I will feed back once i've made these few changes.