Originally Posted by kenwelch
There are left bank and right bank primary sensors (up-stream before the cats). There are 4 sensors total 2 pre-cat and 2 post-cat.
The OBD II code will provide you with a "Bank 1 Sensor 1" or "Bank 2 Sensor 1" location. Sensor codes do not always mean the sensor is bad. So sensor testing or the other engine codes might point you in the right direction when trouble-shooting. How did you decide to replace the sensors?
1. In class I have had rabbits eat the sensor wires on school lab vehicles parked outside. Sometimes you can repair the wire using good soldering methods. Sometimes they eat the wire right at the sensor creating a un-repairable sensor.
2. If you have a lean bank of cylinders the O2 sensor code might indicate there is something like a vacuum leak that replacing the sensor will not fix.
Perfect, thank you for the answer. For that is why I want to replace the o2 sensors is that someone on the forum told me to fix a problem with my M3 at low speed (-1500rpm) when I jump on the gas pedal, the car takes some time to react, as if the car hesitated a moment before accelerating. Also, past 6000 rpm, it seems that the strength of the acceleration is less than before, as if to 6000 rpm it had reached its maximum power..someone has suggested that I replace the o2 sensors on the primary catalysts and also replace the spark plugs.
Input is welcome.