Lennox MLA009S4S-1P - Error Code: E1

129
Error Code: E1
Description: Communicationmalfunctionbetweenindoorunitandoutdoorunit.
General Note: PCBmainchipdoesnotreceivefeedbackfromIPMmoduleduring60seconds.
CommunicationmalfunctionbetweenIPM
board and outdoor main board.
IsthereatleastoneLEDintheIPM
boardlight?
No
CheckthesignalwirebetweentheIPM
moduleandthemainboard,isitcon-
nectedgood?
No
Reconnectandretry.Iserrorstilldisplay?
No
ReplaceIPMboard,andthencheck
whetherthesystemcanrunnormally.
No
Replaceoutdoormainboard,andthen
checkwhetherthesystemcanrunnor-
mally.
No
Replacetheelectriccontrolbox.
Problem Solved.
Yes
Yes
No
Yes
Yes
Yes