system lean "Bank 1"

I was driving my car down the road and got a check engine light. I went to auto zone and got a P0171 Code.
They list 4 possibility's, tho he said it usually is the O2 Sensor.

One thing I was wondering about is the code is a "Lean (something) Bank 1". What is this "Bank 1" thing? I remember on another car it said just an O2 Sensor, not a Bank 1.

I could not feel any difference in performance or running, although for a few months every once in a while it doesn't instantly start right up.
Thank you,
Chris.

I was driving my car down the road and got a check engine light. I went to auto zone and got a P0171 Code.
They list 4 possibility's, tho he said it usually is the O2 Sensor.

One thing I was wondering about is the code is a "Lean (something) Bank 1". What is this "Bank 1" thing? I remember on another car it said just an O2 Sensor, not a Bank 1.

I could not feel any difference in performance or running, although for a few months every once in a while it doesn't instantly start right up.
Thank you,
Chris.

Bank 1 is the bank that has the #1 cylinder. This bank contains #1, 3, 5, and 7 cylinders which is closest to the radiator.

Bank 1 is the bank that has the #1 cylinder. This bank contains #1, 3, 5, and 7 cylinders which is closest to the radiator.So what your saying is the O2 Sensor is not working for half the cylinders but it is for for the other half?

To continue with this please post year , thanks.

Thank you, 1997.

some vehicles use separate o2's to monitor each bank, hence the bank-1, bank-2 code designations. Since generic scan tools cannot read vehicle specific data, that is why it scanned as bank-1. It is basically telling you that your pre-cat o2 is reading lean. This could be from a multitude of reasons, not necessarily meaning the 02 is bad. A vacuum leak, dirty fuel filter, etc... can trip this code.