Originally posted by madmole:
Not as simple as the voltage from the Lambda sensor, Its actually a complex alternating signal and you need an osciliscope to check it. The Computer counts the pulses per second as the shape, the residual dc voltage you see is not the whole story
4.5 volts is approxamately lambda, but I have seen duff sensors give this when well off
Actually, the latest version of OBD II software gives the O2 reading and plots it as an osciliscope reading, indicating rich and lean. If I recall correctly, the O2 sensor is a square wave sensor.
