2011 chevy silverado 4.8 lt 4x4 I have recurring bank 2 o2 sensor heater circuit faults p0050 p0056 p0155 p0161 both bank 2 O2 sensors were replaced by previous owner by a shop and same codes came back.. I got it and figured maybe they put in wrong sensors, I replaced all 4, same codes came back. Sensors test good. I'm getting power at pinks,and ground at tans and pulsing grounds at grey,grey/wh,green,orange/wh, and purples I'm assuming are signals. Fuse 8 and 18 are good with power. Also checked engine grounds What can I look for next? Thanks
