o2 sensor reads .1, replaced and same issue. bad ecu?

[jonathancullen]

I have been having issues with my tsi and recently got v3link cable and am using it as a datalogging with a laptop. It reads that my o2 sensor is at .1-.14 volts, a buddy let me try two different good o2 sensors, one oem and one denso. and both had the same results. Now i am wondering if my ecu is bad or if there is something between the ecu and the o2 sensor (relay of some sort) that could be bad. Any help is greatly appreciated.

Edit: btw no CEL or codes come up

 

[TrevorS]

There's no relay between them, but it's always possible the harness connections need cleaning.

 

[jonathancullen]

Alright ill check that out, its just confusing that its happening. Car sat for a couple months for maintenance and now its acting up.

 

[TrevorS]

That's the difficulty of bringing an older car out of mothballs, there's no way of knowing what has gone wrong due to not being run. My suggestion is start with the connections and ECU scan results and go from there. Hopefully, it will ultimately turn out to be reasonably repairable !

 

[wrencher]

Like said above check your connections.
The connector is not in the best place to begin with.

Check the O2 signal wire to the ECU for voltage disconnected key on. It should have a bias voltage disconnected. Like aroung .4 volts. (on harness side of connector)
if not check the wiring back to the ECU.
The o2 check connector isn't grounded is it? ( remember some 1g's having them white wire)

When hot the O2 is capable of producing voltage on it's own, you can check it to make sure it's good connector off correct signal wire.( on sensor side of connector)