York YHKJXH012BAM--FX Service Manual page 126

Trouble 3: Communication failure between indoor and outdoor
start
as per the wiring
no
diagram, check if
communication
wiring is correct
yes
check if the
no
communication port
connecting to the
indoor/outdoor PCB is
in open circuit
yes
replace the
communication
connection wire,
check again
Trouble 4: Indoor PCB EEPROM data is wrong
1.If the failure occurs when being electrified for the first time, that shows EEPROM (8-bit pin) not fixed firmly or
damaged.
2.If the failure occurs when running, that shows EEPROM is faulty and need to be replaced.
Trouble 5: Indoor repeated unit number
Trouble 5: Outdoor unit failure
Check the failure code on outdoor indicator board (5-lamp)
Trouble 6: Outdoor unit alarms sensor failure
start
as per the wiring
diagram, check if
no
connection port
between sensor and
PCB is correct
yes
check if the sensor
no
is in open circuit or
the connection port
to PCB is in good
condition
yes
replace sensor
and check
again
re-wiring, and
check again
if the power cable and the
communication wire are
too close, resulting in the
wrong commission data
yes
adjust the
distance and
check again
re-fix the
sensor and
check again
check if the
no
sensor resistor
value is correct
yes
PCB is faulty
and repalce it,
check again
126
PCB is faulty,
no
replace and
check again
replace sensor
and check
again