A3 (6603) - Transmission bus BUSY error (M-NET Remote controller)

What does A3 mean?

The M-NET remote controller for the Mitsubishi Electric PUMY Air Conditioner is indicating a 'BUSY' status on the transmission bus, which can mean an overload or a communication jam on the network. This applies only to M-NET remote controllers.

• High communication traffic on the M-NET bus
• Fault in a connected M-NET device causing continuous data transmission
• Interference on the communication line

Click steps to track your progress.

1. 1

   Note the error code displayed on the M-NET remote controller.

2. 2

   Power off the Mitsubishi Electric PUMY Air Conditioner system at the main electrical breaker.

3. 3

   Wait for at least 30 seconds, then restore power to the system.

4. 4

   If the error persists, contact a qualified service technician to diagnose the M-NET communication bus and connected devices.