there are upstream and down stream sensor.bank 1 is driver side location of the exaust manifold bank 2 is passanger.sensor 1 is before the catalityc converter and sensor 2 is after.And just to for-warn you a new sensor is about 80 bucks
On a Ford Explorer , Ford Expedition , bank 2 is the drivers side of the engine
Sensor 1 is in the exhaust before it enters the catalytic converter ( upstream )
The oxygen sensor bank 1 is located in the exhaust manifold. The oxygen sensor bank 2 on the 1996 BMW 328is is located in the head pipe.
3, sensor 1 bank 1, sensor 2 bank 1, sensor 2 bank 2
Your in luck...that should be the oxygen sensor in the exhaust manifold at the front of the engine compartment. Bank 2 is the bank of cylinders that does NOT contain the #1 cylinder. That bank is bank 1. Sensor 1 is the oxygen sensor upstream of the catalytic converter, and sensor 2 is the one after the cat.
Bank 1 is the bank that sits closest to the front of the vehicle. Bank one is the bank with cylinder # 1. You have 4 oxygen sensors, (bank 1 sensor 1, bank 1 sensor 2, bank 2 sensor 1 and bank 2 sensor2). Follow the exhaust from the head of bank 1. The first sensor you come to is sensor 1, the second is sensor 2.
Try to picture this Bank 1 Sensor 1 Bank 2 Sensor 1 Catalytic Conv. Catalytic Conv. Bank 1 Sensor 2 Bank 2 Sensor 2
Bank 1 sensor 2 is the sensor after the catalytic converterBank 1 sensor 2 is the sensor after the catalytic converter
Bank 1 is cylinder 1 side of the motor. Sensor 2 is the back oxygen sensor (after the catalytic converter.
Bank 1 is the oxygen sensor either screwed into ,or above the catalytic converter. Bank 2 is below the catalytic converter.
Oxygen sensor: bank 1 sensor 2.
The P0155 refers to the Oxygen sensor on Bank 2, sensor 1. Bank 2 on your vehicle is on the passenger side of the engine. Sensor 1 is the first oxygen sensor in the exhaust pipe coming from the engine.
Bank 2, oxygen sensor #1, is located towards the left front (drivers) side of the vehicle. It will be directly forward of the catalytic converter, and to the left of the transmission pan.
Bank #1 is the passenger side of the engine , and sensor # 2 is in the exhaust after the catalytic converter ( downstream )