Questions, have code "P0140 bank 1 sensor 2 no activity"

[MTZI30]

So i have to get my car smogged next month and I have a cel. Code is P0140 bank 1 sensor 2, no activity. There is a tsb that says replace both rear 02 sensors. Just graduated college so cant spend too much. I do get a disocunt on parts but even with it, im looking at 150 per sensor from Nissan. I've used rockauto.com before. To me, for the most part an 02 sensor is an 02 sensor. Rockauto.com has companies like bosch and desno...does it really matter? They both have one year warranties. Can i get away with just doing one? Im wondering why the tsb says to replace both. Any other suggestions? Help is appreciated. TTTTTTTThanks!

[loystock]

You can replace HO2S2-B1 sensor only at this time and most likely it will fix the problem, assuming you don't have any other fault code. The OEM Bosch O2 sensors is really expensive, @ $150, but an NGK/NTK OEM-compatible, P/N: 24574, is good and priced right. Most sites sell this for @ $90 + shipping but you can get it right now from Amazon for $73 with free shipping. See link below.

http://www.amazon.com/NGK-24574-Oxygen- ... B001PN8TJA

That particular O2 sensor is mounted in front of Bank 1 Pre-Cat (horizontal mounting below engine) with a WHITE harness and a 4-wire connector in front of the radiator. Safely jack up the front pax side and then look at the exhaust manifold below the engine. You should be able see the HO2S2-B1 sensor. It is highly recommended to use an O2 sensor adapter (@ $10) but for this particular application, a 7/8" open end wrench will do the job. Apply a liberal amount of WD-40 and the likes before attempting removal. NEVER DROP an O2 sensor as it can get damaged. Make sure you apply anti-seize compound (comes with the part) during installation.

[MTZI30]

Right on buddy thank you! Do you have any idea why that tsb says to replace both rear sensors? Maybe just to match two new sensors? Do you happen to have any updated disgram? I searched and saw the older one is just a red x now.

[loystock]

If you have the resources, it's a good idea to replace both sensors. An O2 sensor has a typical lifespan of 100,000 miles. In fact, the ECU uses the front O2 sensor for fuel metering while the rear sensor is mainly for diagnostic. Below is a link for O2 sensor location, etc.

http://infinitihelp.com/diy/i/projects/ ... cation.htm

[MTZI30]

Hey man do you know the ntk part number for the other rear 02 sensor? I;ve gone on a few sites but they seem to be confused because of the posistioning of the sensors.

[loystock]

HO2S1-B1 NGK/NTK P/N: 24619. Sensor is mounted on vertical portion of Bank 1 exhaust pipe with 3-wire connector near main engine harness, rear pax side. See link below from our sponsor, NGK.com, a.k.a. "sparkplugs.com."

http://www.ngk.com/results_app.asp

[MTZI30]

Once again thank you! Thats what i thought and when i went to order it, it said "THIS PART DOES NOT FIT YOUR CAR!"

[loystock]

The web site admin at amazon or other site needs to do further research as it is a not uncommon response for this kind of inquiry.

[MTZI30]

Hey buddy so im looking at that diagram and it shows 24619 as a 3 pronge front 02 sensor. I was thinking i needed h02s2-b2 to go along with h02s2-b1 to cover both rear 02 sensors? However on NGKs site it says that 24619 is a 3 pronge rear 02 sensor? Im so confused lol. Arent both the rears 4 pronged?

[loystock]

Did you read my previous post. 24619 is the Bank 1`front sensor. Bank 1 is located at the rear of the engine, Bank 2 in front. If you need Rear O2 sensor, then look for the listing that show Post (after/downstream) Catalyst. All fronts sensors have 3-wire connector while rear sensors have 4-wire connectors.

[MTZI30]

Oh ok. I wasn't differentiating between location on the car and location on the piping. I need the two post catalysts 02 sensors that are both 4 prong to complete the tsb...

[loystock]

Then it will be 24572 (HO2S2-B2) with RED harness and 24574 (HO2S2-B1) with WHITE harness. Sensors are close to one another and connectors are side-by-side, facing the radiator.