Check engine light on.  For a couple of weeks.  Finally scanned code with VCDS and got:

 

Mode 03: Emission related fault codes

Address E1: 1 Fault Found:
P0141 - Oxygen (Lambda) Sensor B1 S2; Heating Circuit: Malfunction
 

 

Which O2 sensor is it the upstream or down stream one?

 

thanks

 

Greg

 

S2 = downstream sensor.

Any work done to the car recently that might have required unplugging the rear sensor?

No work, this an extra backup car the son used to drive.  I started using it because my Passat's fuel pump died.

 

But i will check the connector before I put the sensor.

Edited March 15, 201511 yr by gregB

The good news, on the downstream O2 sensor (after the cat) you can go generic. 

I see. Definitely check the wiring first. It possible it has rubbed on the heat shield and chafed or cut one of the wires.

Thanks guys.  Got the fuel pump into the passat 4motion yesterday. Now assuming it stays drive Subby is next.