Have 1999 toyota camry 2.2 has .995 volts to bank 1 02 sensor at all times even with sensor unpluged
With the sensor ice cold it usually should have .450v/450mv, HOWEVER, does your camry have an AIR FUEL RATIO SENSOR instead of a traditional Oxygen sensor? If so then the 450mv rule no longer applies, and neather does the consistent switching from .200-.800 warm. Air Fuel sensors tend to be frozen (They arent, but kinda look like it at times) around 330mv, and dont move much save a really hard acceleration. They measure amperage not volts, but the scanners arent much help with that and neither are conventional testers. If your car has O2 sensors, then test the signal line unplugged, .450 is OK. By test I mean test the votage, not look at scandata. They arent alwayst he same. If there is 450 but the scanner says 950, Id expect the scanner is reporting more volktage due to a bad ground for the computer or possibly the sensor. You will want to check or augment the grounds are retest(All grounds must show zero volts when the system is ON, and ALSO show zero OHMS when compared to battery negative!). .If there is 950mv on a cold engine that hasnt been started yet with the O2 plugged or unplugged, my 1st recommendation would be visually follow the O2 lead as far as you can and look for any oil intrusion into the harness, repairs (electrical tape, crimp connectors) and check in those areas...check for contact between multiple wires, and check to be sure CORRECT wires were repaired previously and not crossed). If there is no obviously crossed or shorted wires, it is possible there is a rub-thru somewhere, or the PCM itself could have been damaged and actually shorting the sensor circuit. unplugging the PCM and retesting at the O2 sensor plug should then show you ZERO volts. If it still has the 950 with sensor AND computer unplugged, then absolutely you have a short SOMEWHERE. If it goes to zero, unplugged. you may have a problem in the grounds or the PCM or the sensor itself.