First of all, remove cabin air. To replace the o2 sensor bank 1 sensor 2, you’ll be working behind the catalytic converter on the bank 1 exhaust line Check out how to change your o2 sensors specifically the post cat sensor 2 for both bank 1 and bank 2 on the m54 engine
Bank 1 Sensor 2 - What Does It Mean?
In this video i go over all the steps needed to replace both oxygen sensors on the bmw e46 platform especially for the 316i and 318i models with the m43b19tu engine.
A bad oxygen sensor before catalyzer on bank 1 has caused me rough idle, misfiring codes and deteriorated the situation into limp mode
Once you've wiggled the heat shield back, you can see the pair of o2 sensors (bank 1, sensors 1 and 2) sticking out of the exhaust pipes where the three sections of pipe merge into one. I've attached below the ista screen from when the local bmw dealer scanned the car and determined that they would suggest to replace the bank 1 pre and post o2 sensors. I also discovered that the bank one sensor, which is longer than bank two, is the perfect length for bank two I am going to use two bank one sensors and swap the connector on one of them.
