P0134 after replacing the y-pipe

[Bene]

04 D2

tl;dr: ECU reported bad cats, changed y-pipe. Now it's throwing P0134, O2 sensor bank 1 sensor 1 no activity. Could it be an exhaust leak or is it more likely that I yanked a wire somewhere on the O2 sensor?

So I recently rebuilt the engine (in no small part thanks to Dweb and its users). After chasing codes and vacuum leaks, I got it down to P0430 and P0420 which pointed to bad cats. Not surprised as it had been running rich for who knows how long before I bought this thing. So I replaced the Y-pipe with a new one off of ebay.

Now, as the title says, I'm getting a single code [ P0134 ] which says "o2 sensor no activity for bank 1 sensor 1". My first thought was that maybe I yanked a wire somewhere on the O2 sensor, but after some googling it looks like there's a few things that could throw this code. An exhaust leak is possible, but I would think that would also throw lean codes.

Both upstream O2s are brand new Bosch units.

Any thoughts from you wise Rover gurus?

 

[rovercanus]

Have you actually checked feed back from that O2 sensor? It's possible for it to be dead out of the box or damaged when it was reinstalled in the new y-pipe.
Make sure your connectors are plugged in all the way, they can be a bitch to get to.

 

[Knightspirit]

I am just about to order a new Y-pipe myself from Ebay - did yours come from the company in Canada? You could try swapping the new 02 sensor that is reading as bad into a different port, and then rechecking. If it's bad - you should see it showing as bad at the new location (I don't believe that they are location specific?). I assume that you ordered the new gaskets for the manifolds and the olive seal for the rear - if not then that could be a cause?

 

[discostew]

The terminals like to back out of these connectors. Look to see that none of them look at the weather packs at the back side of the connectors and make sure they look like they are fully in the plastic connector body.
These things are so fragile that like mentioned by Canus it could be bad out of the box Or damged when you installed it. Some o2 sensor wrenches will dent the metal case of the sensor and that will short it out internally.
I know its a bitch to get them out but you could switch the front ones side to side and see if the code follows. but because they are so fragile I probably would leave the working sensor alone.
if the voltage is fixed at or near .45 volts then it might not be getting a ground from the ECM. But that I kind of doubt because it was working before.