Carrier DHMSHAQ09XA1 Service Manual page 20

DIAGNOSIS AND SOLUTION (CONT)
Zero crossing detection error diagnosis and solution (E2)
Error Code
Malfunction decision conditions
Supposed causes
Troubleshooting
Check if the connections and
power supply are normal.
Indoor main PCB is
defective. Replace indoor
E2
When the PCB does not receive a zero crossing signal feedback for 4 minutes or the zero crossing
signal time interval is abnormal.
·Connection mistake
·PCB faulty
Yes
main PCB.
Correct the connections. Turn on the
No
unit when the power supply is good.
20