Hi I have a 2000 durango with this code p0161 everyone says I should have 4 02 sensors in Ca. I can only find 2 and if it is the second one downstream then how do you remove it? You cant even see or get to the pigtail to unplug it.do I just get a universal and cut the wires. Is there an inspection plate above the transmission which would allow you to get to the plug . my hands are to big to even move the wire-harness to look for the pigtail. any help would be appreciated Thanks TJ

 

I believe in CA. they require 3 or 4 cat. converters as well, two are right after each exhaust manifold for sure. As for the O2 sensors, there should be 4 only in CA. and 2 for other states, but I want to say in your case 3 are for just monitoring the cats. and one is for adjusting your fuel/air raito. If the O2 sensor that is bad is only for monitoring a cat. just go ahead and replace it with a direct fit cheap one from autozone (I'd stay away from universal ones no matter what the case), if it's for adjusting your fuel mixture then go straight to the dealer and shell out the cash for a new one.

To remove the sensor you either need a 7/8 (I think) deepwell socket or open hand wrench. To install them you're best off just using a special O2 sensor socket.

 

I dont have a problem unscrewing the sensor I can't get to the wire connector I still can only find 2 02 sensors on the driver's side 1 befor the cat and 1 after the cat

 

The connector before the main cat is mounted to the transmission housing and the connector for after the cat is mounted to the transfer case housing, but these are for the pipe after the Y pipe going down the passenger side.
On the drivers side you might be talking about one of the cats after the manifold and before the Y pipe. I never messed with a D that has the CA. exhaust on it. Possibly someone was in there before and just spliced a universal one on, if you find butt connectors on the wires. If the wires go all the way into a harness maybe since they are so close to the front, or added on later for CA. they just don't have connectors.

 

some misinformation in here,
CA emissions vehicles have 4 O2 sensors: correct

there are 3-4 cats: close enough, there are 3, one on each bank and one in the main exhaust line before the muffler

3 of them are just for monitoring and one is for adjusting a/f : INCORRECT
there are 2 on each bank of cylinders, one pre cat and one post cat, the pre-cats monitor mixture, and the post cats monitor cat performance.

from what he is describing he does NOT have california emissions, sounds like he has the standard emissions which only has 2 O2 sensors, one pre-cat (monitors mixture of both banks w/ one sensor) and one post cat (monitors cat efficiency)

If the O2 sensor that is bad is only for monitoring a cat. just go ahead and replace it with a direct fit cheap one from autozone:incorrect many people before you have made this mistake and ended up at the dealer for the o2 sensor bc the autostore unit didnt work as intended, sure some people get lucky, but the vast majority have problems, save yourself the aggravation and just get the dealer sensor that WILL work

if you are still having trouble finding the sensor after his description of where to look for the plug (it should be there) then go to the FAQ thread and download the manual for your year (98-00 will dl the 98 manual, 00 should be there, and 01-03 should use the 02 manual)

 

well it turns out I have 4 02 sensors and 3 cat. now if my code is p0161 book says downstream 02 sensor heater circut problem So would that be the passagners side 02 after cat?that one I think I can remove

 

P0161 says bank 2 sensor 2 so that sounds about right to me. To double check, if you have a multimeter, just check for some resistance on the 2 white wires coming out of the sensor, if you're getting an open or shorted closed reading then it's deffinatly that one.

 

yup sounds like you got it

 

Bank 1 is on the drivers side, bank 2 is on the passenger side.

Bank 1/1 is drivers pre
bank 1/2 is drivers post

Bank 2/1 is pass pre
Bank 2/2 is pass post

Some systems have 3 sensors. one each side pre cat, and 1 post cat for a total of 3.
Bank 3/1 is drivers pre
Bank 3/2 is pass pre
Bank 3/3 is post

 

Just want to thank everyone for your help. You need to be a verry small person to get these things out . what wuld happen if I just spliced the wires (bad things) bought this car for my last one in my old age didnt realize i could not afford to have it worked on. ahh the golden years the only reason they call it that is it just costs you more Gold