Bank 1 Sensor 2 O2 Replacement
 

Some people have asked me to post this when I was done and I have noticed this has been a problem for alot of people recently. So here it is!

I was pulling codes P0139 and P1147. I had reset them before and they came back twice so I knew they weren't just a ghost code.
I ordered the O2 sensor from Dave B and he had it here in two days. :doublethu

Here are some pics of the exact sensor you will need for B1 S2.

http://epacy.com/MaximaPics/IMG_0381.jpg
http://epacy.com/MaximaPics/IMG_0386.jpg
http://epacy.com/MaximaPics/IMG_0387.jpg

The wire and sensor are the exact same in every regard to the factory one. As you can see there are five clips on the wire that are used for wire placement so it does not lay on any exhaust parts.
For the existing wire I pretty much just ripped out the existing clips as some were in very tight spots and it was next to impossible to take them out normally. Just be sure you have ahold of the right wire. The red harness O2 sensor runs along the same line pretty much as the white.
Here are the tools I used minus the typical jack and stands.

22mm open end wrench - I had bought the O2 sensor socket but it was too long and the way the O2 sensor was positioned on the y-pipe it made it impossible to get on as the downpipe was in the way. At least I have it for next time. You know there will be a next time with these cars. The O2 sensor doesn't require nearly the strength you think it would to loosen it. I have a skined elbow to attest to that.
11in Pliers - You could pretty much reach all the other placement clips with a regular set of pliers, but the second clip from the O2 sensor is pretty far up there.
Allen Wrench - This was to gain easier access to the O2 sensor plug (dark blue) right under/next to the engine cover.

I cleared the code with my CP9145 and I drove around a little bit. Although it usually takes 2-4 days for the code to pop again if there is still a problem with the O2 sensor. I doubt it will come back, at least for that sensor.
http://epacy.com/actron.jpg

So far no light. The TSB says to replace both rears at the same time. Hopefully only one needed to be replaced.

keep us posted

Good thread, thanks Eric. And yeah keep us posted.

Does a bad o2 sensor show any noticeable power/performance difference?

i have this code also. how much u pay for the sensors?

i thought this was just the sensor was just oversensitive. I chronically throw p0138-139's. That was "rear bank" o2 sensor, right?

I paid $108 shipped for the one sensor.

I don't think it does.

I just went through this exact scenario. I only replaced the one, and it's been over a week and no codes have back. You really don't need a picture or anything to look at. The 02 sensors are color coded. I did the same thing as you EPacy, just yanked the little clips out. I'm sure soon I'll have to replace some of the others, as I'm at about 85,000 miles.

Thanks for the writeup Eric, I have this exact same sensor to replace now so I am glad that you did it before I did. I picked up my new B1-S2 from Dave B at Maxus on Saturday so now I just need to do the damn thing.

Actually, this can be a significant gas mileage reducer since you will be running rich (in most cases). Performance wise, you won't see much difference.

I believe the rear O2 sensors just monitor they don't actually affect anything. I have a document on this but it is at home. I notice no mpg decrease while my sensor was bad. My idle was pretty rough though during that period.

i noticed my gas mileage go down. i dont know how accurate my trip computer is but it shows 17mpg and before i used to get around 21pmg.

Was that over a period of time? A tankful?

yeah that was a tank. i got 200 miles from a tank. i just bought the 2 sensors that the tsb says to replace.

Let me know how hard it was to replace the other sensor. Incase I have to do it.

Just finished replacing the B1-S2 and it took me about 15 minutes. I have the car unplugged right now for the overnight hours and will see how it runs in the morning.

yeah i had my car battery disconected overnight and today when i turned it on, the cel was gone but i know it will come back. my sensors are supposed to be here this week.

Dave B hooked me up and brought my sensor to Maxus on Saturday along with two new front upper strut mounts. I am hoping replacing just the one sensor will fix the issue but who knows? The old sensor is sitting right here and looks fine to me.

how was maxus? i wanted to go.

Maxus was definitely a blast and getting to meet everyone that I have conversed with online for the past two years was great. Maybe you can make it next year, I hear Vegas is an option.

that would be the bset.

Just changed my P0138 Bank 1 o2 sensor.
 

Well I just changed mine sensor and the SES light was still on. I disconnected the battery for like 15 sec. and it was still on. So I guess the battery should be disconnected for a longer period of time, or what??? How did it work with your Max guys.

I left mine unplugged overnight but I think there is a certain ECU reset procedure for the 3.5Ls.

i changed mine today but i have yet to start and drive the car casue my batter is dead. now i have to go down to costco and pickup a optima redtop. lucky me.

I went to Jiffy Lube and they reset it for me.

Did they charge you anything? And how long did it take?

Shurik, I sent you a PM.

Well I have driven on the changed O2 for almost a week now and no codes have popped up since I changed it. I just drove 230 miles to KC and still no code. I am most pleased. I didn't reflash my ECU I just reset it. I might eventually get it reflashed.

Update
 

Ok, another update on how the car runs after the changed O2 sensor.

I drove to KC and back this weekend. Here are some specs on the trip back.

Average MPH: 83 on highway-77 overall

MPG: 29

Temp: 77-82

I am most pleased with the MPG. Shows everything is operating well and it is more than the Max is rated for. I understand some of the things I have done to the car should help the MPG, but just pleased with the number itself.

The fuel was a mix of 1/2 tank of 91, since that is the highest they had in Blue Springs and 1/4 tank of 93. Both from Phillips 66.

Glad everything is going well after the repair Eric. :thumbsup:

Hey Eric, was that mpg number computer indicated or what your actual calculations told you?

I also have not had the CEL come back on since replacing the O2 sensor last week, but my gas mileage seems to have gone down (is that possible? probably not, lol)

That is what the trip cpu gave me.

That is weird your mpg went down. How much did it go down?

Who knows -- all I know is that I was at 230 miles on the odometer with just below half a tank left when I changed the sensor and then from there it was only 90 miles until I was on empty.

Lots of good info. I just purchased an 02 and it was giving a P0158 code at the dealer. It was an ebay motors purchase, so I didn't have time for the guy to fix it before getting on the road to get back home. Dealer replaced the o2 sensor in the front of the engine, by the radiator, and the light was off. As soon as I drive the car away it comes back on. Guy ran the code again and it was still P0158, did he replace the correct sensor? Or does it just need to be reset overnight? I've tried to reset procedure of waiting 3 secs, gas pedal pumping, etc but no luck getting it to reset so far. I think my timing is off a little, the stickies say timing is critical. Either way, does anyone have a scematic showing all the O2 sensors, or can tell me the difference between bank 1, 2, etc. Thanks,
Jason.

I have a O2 Sensor Fault PO155. Sensor 1, bank 2. Did anyone reprogram the ECM when replacing the O2 Sensor?

Dude, just replace the sensor and reset the ECU (disconnect the battery for >20 minutes) and you should be good to go...

I just reset my ECU as well. Does anyone have specific knowledge of what the reprogram/flash of the ECU does? It wouldn't make much sense to pay for .5-1 hr of labor if it doesn't specifically do anything other than what the reset does. I hope someone has intimate knowledge of what the reprogram does.

igsy: Now I'm just responding to bring my responses above the required 15. btw: If you don't have one, Canadian Tire has the OBD II Code Reader on sale this week for $150 + Tax... Its the older one that has the book listing the fault codes, but it works just the same as the one with the code definitions built in for twice the price.

Another update
 

Been over two weeks and still no code. MPGs are good and car runs well.
Looks like replacing only one sensor was the fix.

I'm pulling code P1147 for the 2nd time in 2 months. I'm getting about 320-350 miles per tank.