Carrier 42QHC009DS Service Manual page 37

9.2.5 Open circuit or short circuit of temperature sensor diagnosis and solution(E5)
Error Code
Malfunction decision
conditions
Supposed causes
Trouble shooting:
Check the connection
between temperature
sensor and PCB.
Yes
Measure the resistance
value of the sensor
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 will display the failure.
Wiring mistake
●
Sensor faulty
●
PCB faulty
●
No
No
Correct the connection
Repalce the sensor
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