The . It indicates that the primary control board (PCB) is actively waiting for a network handshake or response from a connected peripheral device.

The motor is struggling to spin, drawing high current.

If two controllers are wired to a single indoor unit, ensure one is explicitly designated as and the second is toggled to Slave . 4. Inspect the Interconnecting Signal Cable

If none of the above steps resolve the issue, it's possible that a faulty component needs to be replaced. This may include:

Turn off the power at the main circuit breaker for at least 5–10 minutes to clear the temporary memory of the microprocessors.

An internal short circuit, an open circuit, or degraded electrical insulation within the compressor's internal coils will cause uneven phase rotation. The control board detects this as an invalid rotor position. 3. Loose or Corroded Wiring