02 sensor voltage range a/f reading?
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02 sensor voltage range a/f reading?
I know this is an old thread but my issue is similar. I’ve got a 99 Civic that was getting a code for the downstream o2 sensor. Voltage. I plugged in my obd2 tester and watched the live data. Volts stuck at 1.25v. Replaced the o2 sensor and now volts are 0v. Unplug the o2 sensor and volts shoot up to 1.2v and cel turns on. Got me. O2 for upstream is on the money. The trim for downstream is fluctuating as expected. Is this normal? If not, what am I missing?
Last edited by TomCat39; Dec 13, 2020 at 10:33 AM. Reason: adding old thread url reference
