o2 sensor wiring problem?

[XTurboSpYderX]

ok... on my 91 Talon TSI... my o2 sensor was about 400 miles old... I got an o2 sensor CEL, and I lost my A/F gauge, I had 00.00v on sensor 2 on my S-AFC, and I got 00.00v from my o2 across the board on my data logger... so I bought a denso o2 sensor, installed it... and I still have the same problem... I am an aircraft mechanic, so changing parts is no problem... but I am almost clueless about wiring, but I want to fix this myself... where should I start looking

 

[ltvarney]

If you know the o2 sensor is OK, all you can do is trace down the wiring fault with a voltmeter. That would involve probing at the o2 sensor wire, the test terminal in the passenger kickpanel, and on the ECU. Somewhere between the three you might find the spot where the signal degrades.