AH500 Module Manual 3.5 Troubleshooting 3.5.1 Error Codes 3.5.2 Troubleshooting Procedure 3-30 ERROR Error RUN LED Type Description LED Code indicator indicator 16#A600 Error Hardware failure OFF ON 16#A601 Error The external voltage is abnormal. OFF ON Description Procedure Hardware failure Return the module to the factory for repair. The external voltage is abnormal. Check whether the external 24 V power supply to the module is normal.