Mitsubishi Electric City Multi PQHY-P72 Service Handbook page 243

[ IX Troubleshooting ]
High pressure sensor failure (BC controller)
Error Code
5201 Liquid side
5203 Intermediate
Error definition and error
detection method
When the pressure of (1) High pressure sensor fail-
4.06MPa [589psi] or more
is detected by the pressure
(2) Inner pressure drop due to a
sensor, an error code
"5201" or "5203" will be
(3) Torn wire coating
displayed.However, an er-
(4) A pin on the male connector is
ror stop is not made, and
backup operation will be
(5) Disconnected wire
started by other sensors.
(6) High pressure sensor input cir-
Cause
ure
leakage.
missing or contact failure
cuit failure on the main board
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Check method and remedy
Refer to the page on the troubleshooting of
the high pressure sensor.(9.[4].-1-)