I need to know which O2 sensors are which: Bank 1 Sensor 1, Bank 1 Sensor 2, Bank 2 Sensor 1, and Bank 2 Sensor 2. Which are on the engine block and which are on the exhaust?

You did not say what your car was ,however most newer cars use 2 oxygen sensors per bank, if it is a 4 cyl replace downstream o2 sensor,if 6 or 8 cyl bank 1 sensor 2 is downstream sensor on bank that has cyl 1 on it.upstream sensor is in front of catalytic converter downstream is after the cat

Bank 2 o2 sensor 1 is on the back side of the engine. Simply follow the exhaust manifold nearest the firewall the first o2 is bank 2 o2 1 the next o2 will be bank 2 o2 2. The o2 you see by the radiator is bank 1 o2 1.

disconnect the sensors cancel the codes start engine if the codes don't come back replace sensor

standing in front of the vehicle looking at the engine bank 1 sensor 2 is the sensor after the cat converter on the bank on your left
bank one is the left cat ---bank 2 is the right cat. Sensor 1 is the one before the cat and sensor 2 is the one after the cat on either side

Do you know which cylinder on the engine is number 1? Bank 1 is always the side where the number 1 cylinder is located. Bank 2 would be the opposite side. Sensor 1 is always the oxygen sensor nearest to the engine. Sensor 2 is the sensor after the catalytic converter.

that is your o2 sensor near the exhaust manifold rear of engine!!!
hope this helps

Bank 1 sensor 1 --- on left side of engine in exaust manifold .
Bank 1 sensor 2----- on exaust system near converter
Bank 2 sensor 1----- on right side of engine in exaust manifold
Bank 2 sensor 2 ----- on exaust manifold near converter

The "bank" references which side of the engine the O2 sensor is on. The "sensor" references if the O2 sensor is before the cat or after the cat.

Bank 1 is the same side of the engine as the number one cylinder. Bank 2 is the other side of the engine.

Sensor 1 is before the catalytic convert and sensor 2 is after the catalytic converter.

So bank 2 sensor 2 is the O2 sensor on the side of the engine opposite the number one cylinder and after the catalytic converter.

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

Possible O2 sensors:

P2270 O2 Sensor Signal Stuck Lean Bank 1 Sensor 2
P2271 O2 Sensor Signal Stuck Rich Bank 1 Sensor 2
P2272 O2 Sensor Signal Stuck Lean Bank 2 Sensor 2
P2273 O2 Sensor Signal Stuck Rich Bank 2 Sensor 2
P2274 O2 Sensor Signal Stuck Lean Bank 1 Sensor 3
P2275 O2 Sensor Signal Stuck Rich Bank 1 Sensor 3
P2276 O2 Sensor Signal Stuck Lean Bank 2 Sensor 3
P2277 O2 Sensor Signal Stuck Rich Bank 2 Sensor 3
P2278 O2 Sensor Signals Swapped Bank 1 Sensor 3 / Bank 2 Sensor 3
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This is Bank 1 (closer to the dash panel) Sensor 2 (located after the catalytic converter).

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Note: A malfunctioning front oxygen sensor may cause fuel trim codes to set.

1. Several Diagnostic Trouble Codes use specific terminology to refer to sensor location. The illustration and key below explain the following terms:
2. Engine BANK Bank 1 is closer to the dash panel, (also referred to as RH or right hand). Bank 2 is closer to the radiator, (also referred to as LH or left hand).
3. UP Refers to Sensor 1 or "front sensor". It is located closer to the exhaust manifold and before the catalytic converter.
4. DOWN Refers to Sensor 2 or "rear sensor." It is located after the catalytic converter.
5. The following examples show how to interpret oxygen sensor terminology:
6. B1/S1 = Bank 1/Sensor 1 = Dash panel side, BEFORE the catalyst or "upstream"
7. B2/S2 = Bank 2/Sensor 2 = Radiator side, AFTER the catalyst or "downstream"

P0161 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)
check the wiring to the bank 2 sensor, that is the one behind the catalytic converter on the opposite side from the bank where #1 cylinder is located, see firing order diagram below.