The service manual is posted on these forums in PDF format, it's just kinda hidden away in an obscure subforum called "
Nissan 370Z Owners Manual / Service Manuals"
There's info on the TPMS system in WT.pdf of the SM. What's interesting and retarded at the same time is that the system actually does indicate which wheel is having a problem, but it does it via blink codes instead of using the info gauge. The cutoff is 27psi to blink an alert, and the blink codes on the TPMS light for low pressure are as shown here:
So basically if you lose pressure in a tire, the lamp is going to blink in a repeating pattern which consists of:
A start marker, which is 5 seconds on, 5 seconds off.
Then a series of 1 or more fault codes, each of which consists of a number of 1 second slow flashes followed by a number of 0.2 second quick flashes, then a 1.8 second pause between them.
In the case of low pressure, the fault codes will be:
1 second on, 2 seconds off, then a series of 200ms fast blinks, spaced 1 second apart. 5 fast blinks is left front, 6 is right front, 7 is right rear, 8 is left rear.
There are a bunch of other fault codes that can be indicated regarding radio transmission failure, low battery level, etc (per wheel), it's all detailed in WT.pdf.