I got a code P0157 for O2 B2S2 low voltage. I replaced the O2 sensor. The voltage is still pretty low at 0.03 and now the light came back on.
The car has stock header, JoeZ exhaust, and Injen intake, everything else is stock.

- I was told the O2 sensor Bank 2 sensor 2 is located at the passenger side, so I replaced that sensor. A friend of mine told me Sensor 2 should be on the driver side, so I'm consfused and not sure where would the sensor 2 be????
- In case I really replaced the right O2 sensor and didn't solve the problem, what else can I check?

Thank you,

 

Bank1 is Right
Bank2 is Left
(Think LHD vs RHD)

Sensor1 is upstream (before Cat)
Sensor2 is Downstream (after Cat)

Soooo. Guessing it's an LHD (American ISF) so that'd be driver's side after the Cat, which is quite often an air leak causing that O2 to read lean. As usual, start with easier/less costly fixes, there's lots of info via search:

https://www.clublexus.com/forums/is-...s-welcome.html

https://www.clublexus.com/forums/is-...-2011-isf.html

 

I've found a few post on CL and everyone is saying the cylinder layout is
Engine cylinder layout:
8 7
6 5
4 3
2 1
v
(Front of Car)
If that's the case? would bank 1 be on the left side and bank 2 is on the right side?
Today, I found out the problem is most likely exhaust leak. B2S2 voltage is really low compared to B1S2. It only increase at really high rev and won't go pass 0.5V.

 

Last night mine threw a code; P0137 -- B1S2;
So I went and took a pic of the Right Side header flange (where I've had a leak previously) and immediately saw a small hole beside-behind a weld.