I am wondering if anyone can help shed some light on this problem. I had no issues with my oxygen sensors until P0031, P0037, P0057 ("low heater voltage") codes appeared at the same time. These are codes for the bank 1 pre-cat, and bank 1, bank 2 down stream O2 sensors.

I plugged in a sensor I had on the shelf in the bank 2 pre-cat wire harness and it heated up (this was the location that is not getting a code). I then plugged the same sensor into the locations that are getting the low heater voltage codes and they all didn't heat up.

Any ideas on what could case this behavior? I thought maybe a fuse, but all the sensors are on a common fuse so that doesn't make sense. I then looked for any obvious frayed wiring but there was nothing. Any ideas are appreciated. This is on a 2003 G35 Coupe.

 

Sure you are checking the correct fuse?