Does anyone have access to this? I have checked the PDF for this, but it reads as only having (3) wires. (If I'm reading it right) My wiring harness has (4) and the new 02 sensor has (4). Long story short a friend was helping me work on my vehicle and instead of taking his time and releasing the latch on the harness he pulled on it ripping the wires out of the connector going to the wiring harness I have looked all over town, surrounding junk yards and even on line for a replacement with no luck....so I had to cut the new o2 sensor...peel back the covered pair that revealed a black and white wire, which was good but the other two don't match the o2 sensor since one wire is blue and the other blue/yellow....so much for trying to save some money during these hard times......

new o2 sensor has a black, gray and (2) white wires.
ripped wiring harness has black, white, blue, and blue/yellow.

Thanks!

sorry for the late reply; i don't frequent this site that much anymore since i downloaded the pdf FSM file from here....

i have the same year quest

popped the hood and saw the front o2 sensor...

white black white on the wires = 3 wires on the sensor, confirmed

blue-yellow stripe, green, black on the connector side, confirmed

no 4 wire o2 sensor on my vehicle; did you get the correct part? are you sure you're looking at the o2 sensor? (the one threaded into the exhaust manifold?)

also lookup same year mercury villager (this is the last year ford-nissan had made a joint venture for this generation minivan) and confirm part numbers the same!

No problem, I finally figured it out by luck the other day.
O2 sensor black(signal +) goes to Black on wiring harness
O2 sensor gray(signal -) goes to White on wiring harness
O2 sensor white(heater) goes to Blue/Yellow stripe on wiring harness (this doesn't matter if it matches)
O2 sensor white(heater) goes to Yellow/Blue stripe on wiring harness (this doesn't matter if it matches)

This worked for me and my check engine light turned off. After reading some more online, there are ways to test the 02 sensor with a butane torch and volt meter, so I may do that next time before replacing any sensors. I'm not a certified mechanic either, so please double check these codes for yor vehicle.

Cheers!

scratches head...

ooh ok, the 4-wire o2 sensor is the one AFTER the Catalytic converter (DOWNSTREAM)... that's Bank 1?

the FSM only mentions the upstream and downstream o2 sensors

the one I mentioned was the 3-wire UPSTREAM o2 sensor, just for future reference

here's the particular section of the Factory Service Manual:

http://www.nicoclub.com/FSM/quest/2001_Quest/ec.pdf

P0130 HO2S1 (B1) EC-177
P0131 HO2S1 (B1) EC-185
P0132 HO2S1 (B1) EC-191
P0133 HO2S1 (B1) EC-198
P0134 HO2S1 (B1) EC-208
P0135 HO2S1 HTR (B1) EC-214
P0137 HO2S2 (B1) EC-220
P0138 HO2S2 (B1) EC-229
P0139 HO2S2 (B1) EC-238
P0140 HO2S2 (B1) EC-246
P0141 HO2S2 HTR (B1) EC-253

and a better way to test it on the vehicle (without using a torch) is just to disconnect the connector to the sensor and first check for continuity (ohms), then voltage, using the engine's exhaust (start on page EC-196 for more info)

Awesome Thanks!