In Mode 06 (OBD), one gets a current value, max value and a min value for every MID, TID supported. If the current value is out of the max/min range, that MID, TID is considered a 'Fail'. But there may be a case where the current value is within max limits, but very close to it. Though a scan tool will identify it as a 'Pass' , but its almost about to fail. Say, Cat monitor switch ratio (Bank1) has a max 48, min 0 and current 47. So it passes. But the catalyst is about to fail. What will be a range (call it 'Yellow Zone') where I can say that though the Cat monitor switch ratio test passes, yet it is about to fail? Is there any scan-tool which gives this yellow/warning zone signal?
None that I can think of off hand. I know for sure my Verus doesn't or any Snap-On scanner for that matter. Toyota Tech Stream doesn't offer this. GM Tech2 doesn't, and I'm pretty sure the Ford IDS doesn't either.
Mode 6 decoding is spotty at best even in the professional world, and requires a list of TIDs to even decode what test is what most of the time.