York HP Series Service Manual page 111

16.4.12. J0 Malfunction
Malfunction conditions
Possible causes
When evaporator coil temperature is more than 60°C, the unit stops. It starts again
only when the evaporator coil temperature is less than 54°C

Faulty evaporator coil temperature sensor

Dirty heat exchanger

Faulty fan

Faulty PCB
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