Seivice diagnosisDomestic air conditioner11.4.7 The communication fault between IPM and outdoor PCB1) Check whether Terminal CN23 and CN24 on the outdoor mainboardCN10 and CN11 on IPM module2) Check whether the connected wire between IPM and outdoorAre they good?Electrify the machine again and turn iton, Check whether the voltage between1 and 2 of Terminal CN23 is about DC5V,Check whether the voltage between2and 3 of Terminal CN23 is about DC15V,Replace the outdoor mainboard with a new oneReplace the outdoor IPM modulewith a new one.YESNONOYESMalfunction unsolved1) Pull out and reinsert the terminals.2) Replace connected wireMethod ofmalfunction detectionMalfunction detectionconditionsTroubleshootingCommunication is detected by checking the IPM module and the outdoor PCBThe outdoor PCB broken leads to communication faultThe IPM module broken leads to communication faultThe outdoor PCB is brokenThe IPM module is brokenCommunication wiring disconnectedSupposed causes* CautionBe sure to turn off power switch before connect or disconnect connector, or elseparts damage may be occurredLED1 flash 4 timesOutdoor diplay53