P0151-1A & P0051-00 o2 Sensor Bank2, Sensor 1

Hey All,

I am stuck trying to find the root cause of this issue... check engine light came on; checked GAP IID and found the codes (P0151-1A Bank2, Sensor 1 circuit low voltage - general electrical failure - circuit resistance below threshold & P0051-00 circuit low ( bank 2, sensor 1)

I checked, via IID, the output voltage of the post catalytic sensors and bank 2 never gets to the ~4-5v that bank 1 does. ... bank 2 never gets to a closed loop condition ... the lambda wide range output fluctuates around 1.01 for bank1; but stays steady at 1.00 for bank 2... when warmed up i see output voltage from bank1 - sensor 2 at .555v however bank 2 - sensor 2 shows .0400v ... and the post catalytic on bank 1 shows 4.81 while bank 2 reports 0 ???

I have also checked the voltage at sensor 1 - bank 2 - connector harness: both RED (UHEGO A SIG) & YELLOW (UHEGO A GND) show voltage ??? red-sig=2.83v & yellow-gnd=2.47v (cold; engine not running; key on) ... WHITE-GREEN source shows steady 11.97v and the A-HTR wire shows 0v cold and .03v when running (note: i didn't leave running long cause it gets hot down there by the connector)

QUESTION: should both SIG & GND wires have voltage? or should one of them be closer to 5v ? I 'think' i may have a short somewhere .... but that connector goes straight into the ECM ??

what else should i be checking?

Thanks in advance for your help !!

Did you get anywhere with your issue I have the same codes on both banks P0151-1a P051-00 P0131-1a and P031-00 I have replaced both sets of O2 sensors twice in six months and these faults keep coming back I have even checked that the Cats are good. What have you managed to discover ?