Bank 2 Sensor 1

[Astrak]

How easy is it replace O2 sensor Bank 2 Sensor 1 and where is it?

[Logan]

Most GM engines, bank one is the forward bank cylinder postion wise. Typically the left bank.

So for most GM engines, bank one is drivers side (rwd) or the front bank on (fwd).

That being said, the Northstar is set up different. Bank one is the rear bank nearest the fire wall. In this case, the right bank is the forward bank cylinder wise.

Sensor 1 should be directly on the manifold. I personally have never changed a Northstar bank 1 sensor 1. But I understand it is 'fun' to do project. Very tight spaces..

[JimD]

How easy is it replace O2 sensor Bank 2 Sensor 1

No idea, have not had to do that job.

....and where is it?

Bank 2 is the forward bank and you will be able to "see" the sensor in the exhaust collector from over-the-fender after removing whatever plastic panels and engine air intake plumbing happens to be in your way.

[Logan]

Read the post wrong. JimD is correct. Bank 2 is the forward bank on Northstar. Easy fix.

[Astrak]

So it's the pre cat O2 sensor or is it the downstream sensor?

[Cadillac Jim]

It's the one on the exhaust manifold. The HO2 sensors are numbered from the engine down. Sensor 1 is on the manifold. Sensor 2 is at the cat inlet, Sensor 3 is on the cat outlet.