IPDM= Integrated Power Distribution Module. This device, next to the
car battery, houses many of the relays, fuses and distribution circuits for MOST of the car. Nissan/Infiniti IPDMs are, occasionally, the cause of the problem usually because a relay goes bad (as in develops a high resistance contact when closed) however, sometimes the dealer will diagnose it as the entire IPDM being failed.
It happened on my Titan, my dash would go crazy. Turned out to just need updated relays (easy fix).
Anyways, the point is, that if your audio system is acting up, it could be a low-volt issue. I have had also had a low volt situation in my Titan (had that truck a long time, but it's built exactly the same as G37, electrically speaking) due to a weak battery. The voltmeter on the dash always showed a low voltage. Sometimes my radio would act up. I thought my alternator was bad, but I changed the battery first and that was the resolution to that problem. Something was wrong with my battery (dead cell likely) because the truck voltage would never go above 11.5v, even though the alternator was good.
Oh, and I did run the battery in my Q60 down once, and the audio system started freaking out.
If it's your battery, just check voltage with engine running, should be above 13v without AC on. My truck was at 11 and it was freaking out.
If it's the IPDM relay, a little more difficult to find (because it will only show up in one circuit that powers the audio/HVAC control), BUT, the relays are only a few dollars.
Just hoping your car has an easy fix and doesn't need expensive parts!
