P0037 and P0057 after muffler install

[OneBadPorsche]

Picked up an axle back muffler and dual tips.  After a ~ week of running, eventually threw P0037 and P0057.  Cannot clear either.  Both come back as soon as you turn ignition on.  You don't have to start the engine, so I'm thinking it's a ground / short.  I see both are for low voltage.

 

I guess my question more than anything is - how likely is it that both post cat 02s go bad at the same time due to a simple muffler install?  I'm willing to bet it's legit, but want to double check before I start down my path of getting them fixed.  I checked the fuse and it is in tact.  Pulled it, ran it, got the front codes for the forward O2s.  Replaced.  Deleted.  Restart, rear codes return.  So the fronts appear to be working.

 

These say they will fit the 2011 Cayenne with a 4.8L.  And are Bosche OE.  I've heard non OE can trip a light due to incompatible voltage.

 

https://www.carid.com/2011-porsche-cayenne-emissions-parts/bosch-oxygen-sensor-937846187.html

 

Anyone else run into this after simple exhaust installs?  Are these O2's just that flakey?

 

In my Corvette, I just ran O2 simms, but I can't find anything like that for the Cayenne.  I eventually tuned out the rear O2s on the Vette, but I'm not finding much in the way of doing that for the Cayenne.

 

Car was running (and is still running) great after the exhaust install.  So I'm guessing these rear O2s don't do anything more than add to the emissions tax....

 

[Panamera27970]

Hello, were you able to find the faults?  i have the same faults