Hello all, i connected my OBD scanner its reading error code P0051 bank 2 sensor 1 on my '07 lexus rx 350 (japan build), im looking to buy Denso sensor but really don't know the part number to order on Amazon. Is it the air fuel sensor or the oxygen sensor thats deffective ? Please help im really confuse and need some clarification. Thx in advance !!!

 

First thing to replace is the O2 sensor. On those vehicles their are four. 2 pre cat and 2 post cat converter. Each is different in cord length and connection fitting. Make sure you purchase the correct one for whatever bank you are purchasing. Sensor 1 is pre cat sensor two is post cat. Bank one is a set of 3 cylinders that feed into the exhaust manifold, bank two is the opposite set that feed into the separate exhaust manifold opposite of bank 1.

 

Bank 2 is next to the fire wall. sensor 1 is on the top of the exhaust manifold. Parts stores call sensor 1 an "upstream" sensor.

 

Bank 2 sensor 1 is right in front of you as you open the hood and look down. It is also known as the Left, Upstream sensor. Japanese built RX of that year uses a different sensor than Canadian built. You need a Denso sensor part# 234-9008. Only use Denso as it is OEM. Double check everything, CEL, etc. Bank 2 sensor 1 Japan built is Denso 234-9008.

 

So, the diagram above is wrong? It shows Bank 2 Sensor 1 as the one at the back/firewall side.

 

Not sure about the diagram, but I understood bank 2 to face the radiator, and bank 1 to be on the firewall.

 

Go to the Denso global website and search for your spark plug.

Or else google is your friend.

Good luck!

 

That looks correct. I just realized the previous picture also shows an 8-cylinder, so that isn't specific to the RX. Thanks for posting.