o2sensor

This is the sensor on the drivers side before the catalytic converter on the exhaust system. This sensor may be corroded into the pipe. It may take some effort to extract it. However, before you replace any sensor -- the code may come on for reasons other than just a faulty sensor. Perform a diagnostic test and monitor the sensor operation.

Oxygen sensors are identified by bank and sensor position. Sensor 1 is always pre catalytic converter, sensor two is always post catalytic converter. If an engine is a 4 or 6 cylinder engine the whole engine is considered bank 1, if an engine is a V6, V8, V10....., the engine bank containing cylinder number 1 (first cylinder in the firing order) is considered Bank 1, the other bank is considered Bank 2. Interpretation Oxygen sensor designation B2S1 refers to Bank 2 Sensor 1, it will be the sensor on the engine side of the catalytic converter in bank two. Check this link to determine the cylinder that contains cylinder number 1. http://www.wellsve.com/custom_searches/ds_firing.php