View Full Version : O2 sensor readings... whats normal?

02-13-13, 12:33 PM
I drove away from mechanic after transmission rebuild/re-install and got a CEL. Went back. His scan showed a B2S2 O2 sensor, live scan read ZERO volts at idle/rev.

He cleared the code, re-started car and it gets a reading again, but what he described as 'weird' readings, I assume because the voltage bounced around a lot from lean to rich (but no longer zero)

He swapped sensors left to right, experimented more, said readings still look funny but he couldn't get a code so try it again.

I drove home, no code, but later that night got a code. Hooked in with my scanner, showed that sensor at 0V again. Cleared it, went to bed.

Hooked up to my scanner this morning, started it up cold.
Cold Startup:
B1S2 stayed between 0.130-.150V
B2S2 jumped from 0.130-0.700V and everywhere in between every second

When driving, they seemed to be equal, right around 0.675 range. No codes yet.

I know they shouldn't be expected to match, but is that normal behavior on cold startup?