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What is your question?
I got the dreaded check engine light this morning but the car ran fine and the fuel mileage was great so I didn't think it was major. I went to the local Auto Zone and the scanner told me that O2 sensor at Bank 1 Sensor 1 was bad. This is the sensor before the catalytic converter correct?
2 Replies
Correct. 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
FYI - I just had the CEL come on at 65K miles out of the blue. Took it to AutoZone and they read the OBD II codes - P0030 & P0135 which indicate the O2 sensor ($71.39). Haven't had the opportunity to change yet, but I also noticed a slight increase in the coolant temp. I'm going to follow the temp readings before I change out the O2 sensor.