The 2000 MPV contains no less than four O2 sensors in its exhaust system. But which one actually drives the Check Engine Light?

 

That is a necessary evil by law, I believe, and by OBDII stds for sure. You need one O2 ahead of each catalytic converter, and one (heated & expensive) one behind. You have a V6 w/twin downpipes and twin cats, so 4 is the norm.
They ALL can activate the CEL light, just as any other sensor can cause a CEL. That's what makes modern vehicles SO MUCH FUN!!!

Are you having fun yet?

 

Yeah. I had the CEL checked by Autozone, they know it's caused by a malfunctioning Bank 1 O2 sensor but cant determine which one.

 

I have a 2002 MPV LX with 3.0L V6. The code indicates bank1, oxygen sensor 1 . . . on the exhaust manifold near the firewall and above the cat. It is basically just below the middle of the firewall and I see no way to get to it. I cannot even see it from above . . . and from underneath I can snake my arm up so I can barely touch it with my fingertip, but there is no way to get a wrench on it, much less figure out where the wiring connector is.

I have even tried a crowsfoot wrench on my ratchet but, while I can get the crowsfoot on the sensor, the long, convoluted path to a point I could turn the ratchet prevents any leverage at all. My AlldataDIY.com service manual is no help at all.

Do I need to remove some engine parts? Has anyone successfully replaced one of these themselves without special tools? My usual auto shop said it would take at least 1.5 hours. I have replaced one of these on a Mitsubishi 3.0L engine so I know it is not difficult if I can get to it.

Thanks in advance for any help out there!

Greg