Carrier 40QSM009DS Service Manual page 107

16.3.9 High temperature protection of compressor top diagnosis and solution (P2)
Error Code
Malfunction decision
conditions
Supposed causes
Trouble shooting:
Check the air flow system
of indoor and outdoor units.
Does a problem exist?
No
Power off and then restart the unit
10 minutes afterwards
Yes
Check compressor
temperature. Is it within
acceptable parameters?
Yes
Check the refrigerant
system. Is it functioning
properly?
P2
If the sampling voltage is not 5V, the LED will display the failure.
Power supply problems.
●
System leakage or block
●
PCB faulty
●
Yes
No
Yes
Clear up the air inlet and outlet or the heat
exchanger of the indoor and outdoor units.
Check the overload
protector. Is it properly
wired?
Yes
Measure the resistance
between the two ports of
the OLP. Is it zero?
Yes
Replace the outdoor control PCB
104
Ensure a proper
No
connection
No
Replace the OLP