Code Name Causes Possible Solutions LT-1 Cooling Fan Maintenance Time The cooling fan is at 90% of its expected performance life. Use the procedures in this manual to replace the cooling fan. Set o4-03 = 0 [Fan Operation Time Setting = 0 h] to reset the cooling fan operation time. Note: When the estimated performance life is expired, the terminal assigned to H2-01 to H2-03 = 2F [MFDO Function Select = Maintenance Notification] will be ON.