Dsc and o2 fault

Hey guyz just stripped down my gen1 ms3 had all valves done put it back together now i have a fault code for o2 bank 1 low voltage and dsc low voltage also when the car is running i can hear buzzing through the stereo and warning speaker for the doors. I have checked all earths and they seem to be back in there factory locations

 

that's a peculiar one, main ground by the battery I presume is snug? the little guy by the hpfp isn't broken is it? although if that one was broken your injectors would be having a bad time as it's their ground.

have you gone over all of the connectors you took apart not just the ground? that big grey one in the left of the intake manifold can be a duezy to ensure it's fully seated as with the two smaller ones same style by the hpfp area if you took those off, ecu is properly plugged in?

asking as if you've checked the ground then I presume it's a connector issue

 

Check all the connections you touched