The alarm pressure point can be set by you.
After setting the tire pressure to the point you wish, in the glove compartment on the extreme left side, you should see a small switch on the mounting frame. This is the Tire Pressure Reset Switch.
Here are the instructions from the Service Manual: (I don't have the OWNER's MANUAL with me right now.)
4. TIRE PRESSURE WARNING RESET SWITCH
• By operating the tire pressure warning reset switch,
the tire pressure warning ECU can be set to issue a
warning at an inflation pressure that corresponds to
the type of tires.
• Operate the tire pressure warning reset switch only
after the inflation pressures of all tires have been a
djusted on the vehicle.
• To initialize the system, press and hold the tire
pressure warning reset switch for 3 seconds or longer
with the ignition switch on (IG). After the initialization
process has started, the warning light blinks 3 times
(1 second on, 1 second off).
• During initialization, the tire pressure warning valve
and transmitter measures the inflation pressure of the
tires, and registers the signals that are transmitted
into the tire pressure warning ECU at a frequency of
once per minute. The initialization process is
completed when signals from the all tires have been
received.
I have only recently received my TCH,
so I cannot verify this information.
I hope this helps.