Hi, think my O2 sensor in my downpipe on my classic turbo my00 may have failed. I have a Defi AFR guage that is now not changing from a fixed point of about 14.5 Have had a quick look at all the wires and they seem ok. Got a multimeter and the voltage read about a constant 0.3v if a remember right on the wire feeding the guage from the ecu.

 

Had the multimeter out earlier and the reading is 0.33v - 0.35 volts when the engine is running. Is this what it should be reading. I am beginning to think that it may be my guage that has failed as no engine warning light has come. Cheers in advance for any help.