vats system

I'm wondering, i know with the plxr bypass module you wire it in as if your bypassing a passlock 2 system. My question is, could use a 555L to bypass the system also?   Only reason why i ask this is because everytime i goto measure the resistance value in the key, i get the wrong value. I found the listing for all of the different ohm resistance that GM used. Also found one that had where the # of the key matched up with what the resistance value is.

You may have to turn your meter up to 100k or so to get the resistance reading. This reading should be very close to the value that you have matched up to the keys, and you should get the same reading every time, considering that the vehicle must get the same on every time.