Heres the deal:

I measured the voltage on my signal wire of my oxygen sensor. I got a reading of ".491", that was its peak after it ran for a while....idk if thats .49 volts or 4.9 volts. The meter i have had(on the voltage side) options to change the decimal that said "2, 200, or 2000" which one of those should i choose to get the voltage...so if the voltage is, lets say 4.9 volts that it would read 4.9. any info would help.