im fairly certain i have a bad O2 sensor somewhere.. so im wondering what i should do to check them (i dont think autozone or advance will test them)

so.. do i unplug the O2 sensors from above somewhere in the engine compartment, or do i attach the voltmeter directly to the sensors themselvs (it would probably mean more crawling around just to get to them)

if i can just remove the leads from topside and attach them, where would the leads be so that i could get to them?

The easiest and best way to test the o2 sensors is with a scan tool that can display the real time data stream.

whats a suitable scan tool cost?

i may get a scan tool, but if i dont, where are the leads for the o2 sensors so that i may test them with a voltmeter?

U cant really test it with a volt meter, and if u dont know where the leads are then u really shouldnt be attempting to test with a volt meter. Y do u think u have a bad o2 sensor, is there a code, running rough, running rich? The only ones that would cause a running issue are the front 02 sensor, which u only have one.

yeah.. i got a code saying "circuit condition (heated oxygen sensor bank 1 sensor 2)"

then below says probably causes are a defective oxygen sensor, or running very lean or rich

got another code that says governor pressure sensor offset voltage too high or low with an internal transmission failure as probably cause (not sure what to do about that... ill feature it in another post)

and in case i forgot to mention, its a 4.0 engine

anologe meter will not work must bedigital

anolog meter will not work must be digital

well, the downstream sensor was replaced, no more check engine lights now, so all is well