York HP Series Service Manual page 114

16.4.15. J3 Malfunction
Malfunction decision conditions
Supposed causes
At first test the resistance between every two ports of U, V, W of IPM and P, N. If any result of them is 0
or close to 0, the IPM is defective. Otherwise, please follow the procedure below:
When the voltage signal that IPM send to compressor drive chip is abnormal, the
display LED will show "J3" and AC will turn off.
● Wiring mistake
● Faulty IPM board
● Faulty outdoor fan ass'y
● Compressor malfunction
● Faulty outdoor PCB
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