2000 mitsubishi galant

all you have to do is follow the exhaust from the manifold back and you will come to the sensors. bank 1 O2 sensor is on the bank cylinder 1 is and bank 2 O2 sensor is located on the bank cylinder 2 is on. the first sensors you come across is sensor 1 then the next sensor you come across sensor 2 and so on. so you can have a sensor code like bank 1 sensor 2 meaning the sensor on bank one but the sensor is the 2nd sensor in the exhaust.

it is not an O2 sensor but a heated oxygen sensor that is in the exhaust manifold before the cat converter
heated oxygen sensor(HO2S) 1 bank 1 is the one against the fire wall
it is not a heater as such but has an internal heating system so that it reads the exhaust emissions correctly and adjusts the air /fuel settings in the ECM
normally has 4 wires
the oxygen sensor (O2S) is after the cat converters and is a completely different sensor to read a different exhaust gas

p0136 02 sensor malfunction is (bank 1 sensor 2)-- replace 2nd 02 sensor thats in exhaust system. If it is a four cyclinder, then there is only one bank. if its a six then bank 1 is on the side of # 1 cylinder. bank 1 sensor 2 is after convertor. have a good day !

A v-6 or v-8 engine will have two banks. Bank one is the side of the engine with the number 1 cylinder. Bank 2 is the other side of the engine. In your case Bank 1 is cylinders 1-3-5 on the back side of the engine closest to the firewall. Bank 2 is cylinders 2-4-6 on the other side of the engine.

You have two cats bank 1 and bank 2. There are two oxygen sensors before each cat that help determine fuel trim and are refered to as sensor 1 and two oxygen sensors after the cats that monitor cat efficiency and are referred to as sensor 2. The bank 1 sensor 2 O2 sensor is either providing a higher than expected signal or is switching like the sensor 1 O2's. If either of these has occurred the PCM detects that the cat is no longer working as it should and sets the code/turns on the check engine light.

9 times out of 10 it is a cat that has gone bad.

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Bank one sensor is going to be in the front of your catalytic converter and bank two will be to the rear of it. This way your ECM knows how well the cat is working. It will read the oxygen content before the cat and then after.

have the engine light code scanned, and it'll tell you if it's bank 1 sensor 1, bank 1 sensor 2, bank 2 sensor 1, bank 2 sensor 4.

Bank 1 is on the same side as Cylinder 1
Bank 2 is on the opposite side of Cylinder 1

Sensor 1 is located before the catalytic converter.
Sensor 2 is located after the catalytic converter

P0157 Oxygen Sensor Circuit Low Voltage (Bank 2 Sensor 2)

I would try replacing the Oxygen sensor, then clear the code.

The O2 sensor would be the after the catalytic converter ( sensor 2) on the exhaust pipe of the number 2 cylinder uses ( bank 2).

Try replacing the gas tank cover. Seriously. If that does not work, it could be the clutch sensor.

it means the oxygen sensor closest to the exhaust man. is bad , replace

The first sensor closest to the exhaust manifold is for the air to fuel ratio. The second one if it has one will be further downstream and checks to see if exhaust is plugged.

Is your car running right especially at idle????