So i just bought a 2000 maxima se and life was good. Until 2 days ago i go to drop my friend off and i am coming home and whamm.. service engine light comes on. I was hoping it was either the gas cap or my cold air intake became lose again. Check them both and nothing. So i try disconnecting the battery and still came back. So i went to get it checked out and it came back with code p0139, which is a bad o2 sensor in bank 1 sensor 2. The guy there said he didnt know if it was after catalytic front or after catalytic converter back, and there is a huge price difference and honestly i cant afford to buy both. So does anybody know if it is front or back for code p0139. My car is a 5sp manual the mechanic said that made a difference.

 

start in this thread......its actually stickied

http://forums.maxima.org/5th-generat...bs-inside.html

P0139 - Heated Oxygen Sensor 2 Circuit Slow Response (Bank 1)

its the precat, the one before the main cat....you have a 2000, so its the one in the actual Y pipe...and that is actually the rear precat

the front precat = THE precat directly in front of the radiator and inside the engine bay

the rear precat = THE precat directly below the firewall, typically what you would replace if you got a y pipe

my suggestion is to just replace the o2 sensors, CHECK OUT www.sparkplugs.com, and https://www.automedicsupply.com/inde...80&height=1050

 

 

It's the one after the rear pre-cat (if cali spec) or main cat (if federal spec). If replacing with OEM sensor (not universal) it's the one with the white wire.
Diagram below is for California spec vehicles.

 

I got a 2000 Maxima with CEL for about a month now and can not figure it out. I stopped by autozone and the code read, Po171 Bank 1 and Po174 Bank 2. Which o2 sensors are these? Thanks for any help! Could it be a bad MAF? Car seem to run fine.

 

For a lot of org members, replacing the MAF seemed to have cleared those codes and solved the problem.

 

But I dont have the MAF issues. Like stalling or hesitation.......

 

I didn't go too deep while searching for those 2 codes and possible solutions. I did find out that it's fuel injector related. I would try one of those injector cleaners before starting replacing parts. Also, I would monitor the fuel efficiency very closely to see if there's any decrease in the mpg's, provided you have something to compare it to.

 

I running some fuel injector cleaner now. Also going to change the filter, check for leaks, and clean the MAF. Hopefully that will do the trick.

 

Do you know if the 2000 maxima has that U shaped wire? This pic was from a 2002 maxima. I took my sensor out to clean and did not see it....

http://farm4.static.flickr.com/3145/...633cc7ae_o.jpg

 

Last time I cleaned my MAF it did not have a "U shaped wire" on it too (2000), check the "clearn MAF for under $10" thread and there's more info on that.

 

5th gens have seperated temperature sensors.

 

How do i figure out if my car is federal spec or california specs?

 

Under the hood, there is an emission related label. Towards the buttom it reads "this vehicle conforms to US EPA NLEV regulations applicable....." . If that label has the word "california" in it, it's a California spec. Also, if the numbers of connectors right between the front of the engine and the radiator is 4, then it is a Cali Spec. Otherwise it is Federal.

 

Thanks its federal specs

 

Damn my CEL came back on.
Freaking same codes as before - Po171 Bank 1 and Po174 Bank 2

Dont know if it the o2 sensors, the MAF or fuel injectors? I ran some fuel injection cleaner, could not find any leaks and cleaned MAF.
What should I do?

Do I start with the MAF then the o2 sensors..........

 

I have a 2000 SE with 90K miles and I just replaced this O2 sensor. There is a TSB for it here: http://maxima.theowensfamily.com/tsb/NTB02-051a.pdf

It is not too hard to replace, it is right in the middle so I jacked up the front end and crawled in from the driver's side. Mine was in tight and the exhaust system had too much flexibility to get a good torque on it so I had someone hold a long 2x2 against the bracket to provide some resistance while I reefed on it.

It helps to have an O2 socket so you can put an end wrench on the socket and get some extra leverage. I couldn't get a good bite with just an end wrench on the sensor.

The code has not come back so far. Hope that helps.

 

Since both are reading too lean I would expect it to be something that relates to both, like the MAF. They both came on at the same time it is unlikely that both failed at the same time. Unless it was your very first time driving at highway speeds after you bought the car.

To test the MAF get on the highway at about 50 MPH. Floor it and if the engine revs up (~4,000 RPM) but there is no power and/or it doesn't shift then it is probably the MAF. If it pulls fine then your MAF is probably okay.

Caveat - from what I have read MAFs fail in a myriad of ways and what I described above is just how mine failed and how I determined it failed. You can also just check the voltage at various RPMs, but that is a little more intrusive.

 

I have 2002 6-speed. Got the check engine soon warning, changed the sensor at the gas tank and light went out. Now 3 weeks later the light is on again. Do ya think it is the O2 sensor?? Thanks Gary

 

No idea until you pull the codes.

 

Sorry but a dumb question. How do I get the codes?? I have had 2 of these cars (Maximas) and not like my old 76 honda civic which i serviced myself. Time to join the 21 century. Any advice would be appreciated, Thanks G

 

The same way you got them (codes) in your first post LOL, just go to any auto zone in your area they check it for free,also if you just got the car I would change all fluids with the best brand in my opinion and dont beat on it everyday if you dont want more problems

 

Without reader:


Do not start the engine
Precise timing is very important!
Long blinks - 1st digit, short blinks - next three.
10 long blinks mean 0

 

does anyone have the issue where the SES light comes on, then a few days later, it goes off..then a month or so later, it comes back on...few days later its off...anyone? I took it to Autozone and it's the O2 sensor bank 2 i think they said. But if its bad why does the SES light go on and off??

 

The O2 sensor can come back in range. There are several codes associated with the O2 sensor (see here) and if they come back in range the code can reset. I don't know the exact mileage or duration for it to reset and if it is only for specific codes, but that could have been what happened.

For example, I had P0138 and P0139 for the rear O2 sensor. After about a week the SES light went off, presumably because there was nothing wrong in the first place (my MAF was on the fritz).

Best thing you can do is when the SES light comes back on pull the code. It is not bad if it goes on and off (caveat, it is bad if you reset it without diagnosing and fixing the problem). How many miles are on your max?

 

Just bought a 1999 Maxima SE. The wife put about 10 gallons of 87 octane when the low fuel light came on. I filled the tank with 93 octane and checked the fuel cap, but the SES light stays on. Had the OBD scanned and came up with O2 sensor and Knock Sensor codes. I authorized the shop to clean the fuel system--they did not say this would clear the SES light--but I went ahead and had it done. There are no drivabilty issues. Could the lower octane trigger the SES light?

 

The low octane gas caused your engine to knock. Your engine detected the knocking and set the SES light. I am surprised it would happen with only one tank of gas, but these engines (at least mine) knocks badly with anything less than premium.

I am not sure why the O2 sensor was on, but my guess is that it didn't have anything to do with using regular gas. Do you know what the code was for the O2 sensor?

Cleaning the fuel system has no affect on the knocking. Unfortunately that was probably a waste of money. Or should I say an investment in your local auto shop

Either get the actual codes, or run through a couple tankfuls of premium.

 

I did not get the code for the o2 sensor. Is it OK to drive the car with the SES light on?

 

Yes, you can drive the car with the SES light on if you have no other issues, but at some point you may have to deal with it. Give it some time with a different (premium) gas and see if the SES light goes out. The O2 sensor code and the SES light may have been triggered by a higher amount of ethanol (puts more O2 into the exhaust) in that particular gasoline that your wife bought, particularly if you have a marginal O2 sensor or cat. BUT, the pinging by itself will not set a code, or put on the SES light. A "failed" knock sensor will also NOT put on the SES light, but as you do supposedly have the code for the knock sensor it may actually have failed. But run for a bit with the premium gas and see if that stops the pinging no.1, and see how the performance is (lots of "snap", and reasonable fuel mileage), and also see if the SES light goes out. Some members on this forum in the past have reported poor performance (probably from retarded timing) and then later on discovered the failed knock sensor.

 

Thanks for the info. I will run a few tanks of premium and go from there.

 

Ive sneaking up on 118,000... I changed out the O2 sensor with a Bosch one I got @ autozone, but it came back on last night... DAMNIT

 

its acutally not very good to be switching up gas like that. Once you start with one, stick with it. I would recommend trying a fuel additive before changing fuel types. I've personally stuck with mid grade and every 4 months use the BG 44K fuel additive.. Works great! Look into that...

 

Berto210.......I don't know where you got that idea from, but it's incorrect. The Maxi's recommended fuel is a minimum rating (US/Canada) of 91 octane to start with and changing immediately to the recommended fuel is an advantage and not what you suggested (and don't get me going on additives!!). Limiting the use of fuel with ethanol (I know that's difficult in the states) if you can, may be helpful if you encounter what happened to eutecticpt.

 

When did you change the O2 sensor? If it is less than 20K miles (assuming you changed it around 100K) it is probably not the O2 sensor. Has your MAF been replaced?

 

I stand corrected. Thanks for the clarification. Just goes to show you that you should never trust a noob.

 

Seems like no one really answered this question.
I had same code & just replaced mine today on 2000 SE 5 SP Federal emissions. There are only 3 Oxygen sensors on this car.
The Bank 1 Sensor 2 is furthest towards back of vehicle (almost mid way, under drivers seat) AFTER the Cat converter. You can Borrow (for free w/ deposit) a "oxygen sensor remover kit" from Auto zone or Orielly auto parts. After you unscrew the sensor from the pipe on one end, you will then need to unplug it on the other end. Follow the wire and you will see it goes up through the floor of the vehicle under the drivers seat or center counsel carpet.
You DO NOT need to remove the seat, console or carpet!!!
You can unplug the sensor under the vehicle by:
1st pulling down on round black plastic cap (wire runs through it)
2nd Use a screw driver or socket extension to "push up" on the white foam liner (that you can see looking up through the hole under the car) push it up a good couple inches & then hold it there.
3RD This will allow you to gently pull the wire until you see the green plug appear in the hole. Gently pull the wire and use one finger to work the green plug into the vertical position. Remember you have to push up the white foam at least 2 inches before you can do this.
THEN, you will be able to gently pull the green plug down through the hole and unplug it.
Remember, You will NOT be able to pull plug through in the horizontal position because the hole is not big enough, you need to get the plug vertical 1st.
Reverse these steps after you plug in the new oxygen sensor.
Hope this helps someone & Let me know if this works for you!

 

The is very good info, especially the part about pushing up on the foam and rotating the plug vertically to get it through the hole.

Also, the plug itself is a little tricky if you've never seen one like it before (though they are all over these cars). Push in and down on the lever to release. Then, from the inside, poke a little plastic piece out that the lever will pop back out. This "resets" the plug back to its original position. Now you can plug in the new o2 sensor.


keywords: downstream o2 oxygen sensor rear bank 1 sensor 2 replacement plug

 

PB blaster FOR the WIN