Which is bank 1 on a lexus ls430 year 2000. my manual says passenger side and lexus forum says drivers side i,m confused. fualt i have is sensor1 bank 1

no year told at all,
LS430 is a what/
2004 Lexus LS 430 with RWD
well a cars S1 is front sensor O2
bank 1 is the bank that has cylinder 1,
this is called basic basic engine tech ASE class day 1, stuff.
4.2L Lexus 2000 year, first one. to 2006, says engine wiki !
real name is
4,292 cc (262 cu in) 3UZ-FE V8
cylinder 1 on all V engine made is that bank that sites most forward of crank main pulley and cam drive.
looking from the top of any V engine this is clear as day, views
end day1, class


google finds this in 1 second flat
using real engine name.

bank 2 facing front of engine is left.
so B1S1 is right bank front sensor not rear.of cat.
cyl1 is more forward of cyl 2. as V8s all do,
the rods can not occupy the same place on the journals.

It is located on the exhaust manifold and you will need a ratchet and a oxygen sensor socket in order to replace it.

Here is a forum from Lexus owners discussing the same problems that you are https://us.lexusownersclub.com/forums/topic/64288-code-p0171-b1-too-lean

There is 4 of them, one behind each of the exhaust manifolds. Driver side being bank 1 sensor1, passenger side being bank 2 sensor1. And one behind each of the catalytic converters. Driver side being bank1 sensor2, passenger side being bank2 sensor2.

Bank 1 is always on the same side as the number 1 cylinder. Bank 2 is the other side of the engine. Sensor 1 is always before the catalytic converter. Sensor 2 is always after the catalytic converter.

Bank 1 sensor 1 is on the passenger side before the catalytic converter.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

bank 1 is pass/side exhaustpipe/converter bank 2 is on the driverside,this car has two converters, so you have 4 oxygen sensors, one before and one after the converter on each side, so bank 1 sensor1 is pass/side before the converter, bank 1 sensor 2 is pass/side after the converter, then bank 2 sensor1 is driverside before the converter, before means starting at motor, then bank 2 sensor 2 is driverside after the converter, heres a diagram to help, i hope this is helpful.

Bank one is the side that cylinder 1 is located. Sensor 1 is in front of the cat converter, sensor 2 is behind the converter. So Sensor 1 bank 1 is the RIGHT FRONT SENSOR.

This sensor will be located before your catalytic converter and will be on the same side as cylinder 1 of your engine

the O2 sensor for bank one sensor one is located between the catalytic converter and the engine in the exhaust head pipe. see photo of your engine cylinder layout, the sensor u want to replace is the one at the cylinder #1 bank on right.

it is on the drivers side is it upstream or down stream. bank1 sensor1 is on drivers side before converter.