Carrier 40QSM009DS Service Manual page 100

16.3.4 Open or short circuit of temperature sensor diagnosis and solution (E4/E5/F1/F2/F3)
Error Code
Malfunction conditions
Potential causes
Trouble shooting:
Check the connection
between temperature
sensor and PCB. Is it
properly wired?
Yes
Measure the resistance
value of the sensor. Is it
within acceptable
parameters?
Yes
Replace indoor or outdoor
main PCB
E4/E5/F1/F2/F3
If the sampling voltage is lower than 0.06V or higher than 4.94V,
the LED displays a failure.
Wiring mistake
●
Faulty sensor
●
Faulty PCB
●
No Ensure proper connection
No Replace the sensor
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