Hey, i have a 5.5 Maxima. I've been looking up the codes and everything, but I thought Bank 1 Sensor 1 was a secondary. However, i think it might be a primary. Can you guys help me which sensors I need to buy according to these codes? p0031,p0051 , p0037, poo57. I'm sure 37/57 is secondary.Which are Upstream/Downstream? Also we should buy Bosh sensors right? Part # would be a great help. thanks guys!

I'm no expert, but based on those codes you need to replace both sensors on bank 1. Google "maxima o2 sensor location" and look at "images".

Yeah but there have been a few posts stating that the the P0031 code is Bank 2....where some posts say Bank 1 if im not mistaken...

This chart has been noted to be slightly incorrect.... some say p0031 is bank 1 sensor 1... and other posts have said its bank 2....

http://www.nicoclub.com/FSM/Maxima/2002/EC.pdf

DTC P0031, P0032, P0051, P0052 HO2S1 HEATER

http://www.courtesyparts.com/images/a33b/a33b_226-4.gif

Part # 22690 Both say Bank 1 Sensor 1.... So I'm guessing that's Upstream (Primary) So I just need to get the Bosch Upstream sensor right? Which one is which on the diagram though? like bank what sensor what? I've figured that the P0057 / P0037 is the Bank 1 Sensor 2 Rear Downstream ... Bosch 15225

For VQ35DE engine
P0031 & P0051: Primary 02 sensor near the firewall
P0037 & P0057: Secondary 02 sensor with white wire
Causes: clogged or deteriorating precat
Temporary fix: Replace 02 sensor with OEM genuine Nissan parts only.
Permanent fix: gut both precat (one near the firewall and one near the radiator )
Install nonfouler to the two secondary 02 sensor.

the colors on Bosch don't match oem. but the white one would be rear downstream right?

I have a 5.5 and got a P0051 recently and it turned out to be Bank 2, Sensor 1 which is easily seen when looking down behind the radiator attached to manifold right off the engine and the connector goes to the blue O2 connector at the front of the engine. I don't know about the other codes, however, but I can tell you that it's definitely Bank 2, Sensor 1.

Best price I could find was here:
http://www.rockauto.com/catalog/more...id=445&jpid=14

Here's an illustration.



Good luck!

I would swap out the upstream (primaries) with new ones and SIM the downstream (secondary) sensors.


An o2 sim is cheaper & easier to install than the sensors.


If you have emissions testing, simply hide the SIM somewhere the inspector wont see it.


02simulators.com