Not booting up. Stuck in s5/s4 state. Missing Pp5v_sus and pp3v3_sus

I have general question about power rail dependency. Does pp5v_sus and pp3v3_sus depend on smc_batlow_l in anyway? Or the other way around? By the way what does sus stand for?

I am powering a 820-2915 motherboard from my bench power supply and I am having an issue with pp5v_sus and pp3v3_sus being 0V. Smc_batlow_l and pm_batlow_l both are missing.

When I give 3v to pm_batlow_l the Mac starts.

Is it a smc failure or could it be something else I am missing.