Thanks Duke, I understand now.

I was just following what the Service Manual says (07.3.11 I-11/29).

I didn't think the O2 sensor can actually emit half a volt. I guess the O2 sensor is acting as a ground point for pin 8 of ECU ( which is always 450 mV) and its voltages fluctuates around few mVolts.

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Zorin

'88 Benz 420 SEL
'79 Porsche 911SC ('87 Carrera Engine)
'00 BMW 540 Sports Package
'99 Land Rover Discovery

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