Originally Posted by
Blacky
VAT ignition cycles is usually only non-zero while the vehicle is in production at the factory. That allows various operations to be performed on the ECM without the technicians having to be concerned about security issues. The VAT counter should be set to zero by the time the vehicle leaves the factory. If (for some unknown reason) the vehicle leaves the factory with the VAT counter left at non-zero, it counts down to zero at each ignition cycle. That means within a short amount of time the vehicle will return to full secure mode. Once the VAT counter has reached zero it cannot be increased above zero again.
It is most useful when a new PCM is installed in a vehicle and that ECM might have a VAT counter value of 200 or more. Instead of cycling the ignition 200 times you can just set it to zero using that option in EFILive.
Regards
Paul