Ecutalk reads 14.7 psi at idle (from the ecu )as that is atmospheric pressure, but a boost gauge reads that as 0 psi.
There's nothing wrong with your car.
I think they're designed to run the motor and warm it up in cold climates. I guess it helps circulate the fuel quicker and create a more efficient burn of the fuel at a higher rpm...
They work well for getting the aircon to cool the cabin down on a hot day, runs the compressor a bit faster. The Nissan setup is good, the hiluxes I've driven are only a push button and are obviously controlled by the coolant temp through the ecu so they won't increase the idle speed when the engine is warm.