Airwell VVFA Series Service Manual page 50

[28, 29] High/low pressure sensor failure
If voltage between white terminal and black
terminal is 0.5V~3.5V when testing pressure
If sensor terminal is fixed well
Yes
If voltage between red terminal
and black terminal is 5V when
testing pressure sensor by
multimeter
Yes
sensor by multimeter
No
Replace connecting board
No
Reconnect
No
Replace PCB
Yes
Replace pressure sensor
48