Carrier 38MBRQ36A-3 - J5 Malfunction; High pressure protection

38MBR: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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J5 Malfunction
Troubleshooting
Error Code J5
Malfunction decision conditions The sampling voltage is not 5V, the LED displays a failure code.
Supposed Causes
• Faulty wiring
• Faulty overload protector
• System blockage
• Faulty outdoor PCB
J5 displayed
High pressure protecƟon
Are the high pressure
switch and main control
board wired correctly?
Yes
Connect the high pressure
switch and main control board.
No
Is the high pressure
protector broken?
Yes
Method: Disconnect the plug.
Measure the high pressure
protector resistance. If the
protector is normal, the value is
0. Does the problem sƟůů exist?
Replace the high pressure
protector.
No
Is the outdoor ambient
temperature higher
than 122  F (50  C)
Stop the unit.
Yes
Check if the outdoor
unit venƟlaƟon is good.
No
Ensure the outdoor unit venƟůaƟon
is funcƟoning properly.
No
Is the outdoor fan
running properly?
Yes
Refer to the Fan Speed Out of
Control MalfuncƟon soluƟon.
IdenƟfy then cause and resolve it.
No
Yes
Is the
heat exchanger dirty?
Clean the heat exchanger.
Yes
No
No
Check whether the refrigerant
system is funcƟoning properly.
Replace the
outdoor main
board.
Is the problem
resolved?