Rick's Free Auto Repair Advice

Oxygen Sensor Location

Where is the oxygen sensor Located

You’ve got an oxygen sensor code and the description says something like B1S2. What does it mean? What’s the oxygen sensor location?

B1 means the sensor is located on the same bank of the engine that has the #1 cylinder. B2 is located on the opposite bank.

S1 means the sensor is located BEFORE the catalytic converter

S2 means the sensor is located AFTER the catalytic converter

Just remember: An oxygen sensor code does NOT automatically mean you have a bad sensor. The sensor could be telling the truth, in which case you could have an air leak, a stuck open fuel injector, a partially clogged fuel injector, etc, etc. If you like throwing parts at the problem, go ahead and replace the sensor without doing any further diagnostic tests. Just be aware that if it doesn’t solve your problem, the sensor wasn’t bad and you’ve got to explore the root cause of the problem and stop chasing symptoms.


© 2012 Rick Muscoplat

Posted on by Rick Muscoplat

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