# strange O2 readings



## p10driver (Apr 30, 2002)

At first I have to say this is not about a nissan engine (Don't stop to read now. It's really strange. ). It's about my fathers Opel Vectra. But that should not be to bad becouse O2 shoul work the same way...

The car throws the code for mixture to lean so I've checked the O2 reading and when the sensor heat's up it goes form 0.5V to 0.01V. This look's like a weak mixture. But if i rev the car up and release the throttle so that mixture gets real week (fuel cutoff) the reading is -0.7V.

So I decided to remove the sensor and test it. Now when I apply the heating current and the sensor heats up the DMM reads -0.9V when in contact with air. When I put it into the flame of a propane burner the voltage goes to 0,1V.. Hm real strange hu? When it should read 0V it reads -0,9V and when it should read 1V it reads 0,1V (The DMM is conected the right way and is working OK). Anyone seen something like this before?


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## Zen31ZR (Mar 24, 2004)

Try replacing the o2 sensor yet?


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## p10driver (Apr 30, 2002)

I've replaced the sensor and the car is OK now. But I'am wondering what can happen to a sensor to read that values.


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## Zen31ZR (Mar 24, 2004)

p10driver said:


> I've replaced the sensor and the car is OK now. But I'am wondering what can happen to a sensor to read that values.


Did it happen suddenly, or was it always like that. I'm thinking some kind of short circuit inside the sensor itself. I have no idea how they are built internally, though.


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## nova73guy (Mar 30, 2004)

Not too sure exactly what happens inside the sensors, they just go out. No warning or explanation. Just a fact of fuel injection life.


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