How Important is it for Flex Fuel Sensor to have 12V *During Cranking*

[lxcoupe]

There are two methods of powering the flex fuel sensor... 12V key-on (cuts 12V while cranking) and 12V ignition on (keeps 12V while cranking). Is it mandatory that the sensor maintain 12V during starter cranking?

[07GTS]

id say yes as if not then it will prob go to the default failed setting, i made sure i wired mine to ignition 12v whilst cranking

[str8dum1]

of course important. with no value, ecu has no idea what fueling to target