I have a 2001 Honda Prelude SH (Honda H22A4 Engine).
The exhaust has two oxygen sensors; one before the catalytic converter (sensor 1) and one after (sensor 2). Holding at 2500 RPM and sitting still I see:
OBD II engines use one oxygen sensor before the catalytic converter, and one oxygen sensor after the catalytic converter. The function of the second oxygen sensor is to determine if the catalytic converter is functioning. It does this by looking at the difference between the two oxygen sensors. If the catalytic converter is functioning correctly there will be a reduction in the exhaust oxygen content as carbon monoxide and carbon dioxide is catalyzed in the converter.
And my understanding is higher voltage = less oxygen.
So my question is simple: Since #1 (pink) is before the converter, and #2 (blue) is after, the higher voltage on #2 means an oxygen reduction in the converter which means everything in this graph is exactly what I'd expect to see with properly functioning sensors and a catalytic converter. Right?
I know it's a pretty straightforward question, I am just looking for confirmation that my understanding is correct.