I have a AVIC-D3 which shuts down whenever My car is using excessive power. According to my scan gauge the Voltage never dips below 11V but the AVIC-D3 shows only 9V.

Any suggestion to clean up the power signal or is it possible the unit is defective?

Is this with the engine running? If so then you have a problem with the cars charging system.

Actually It was fixed with grounding. I reran the ground & got the +2 Volts Back.