What was found
WITH APU ON, PAX AIR FLUCTUATION; WITH L/H, R/H OR BOTH PAX SELECTED (APU PNEUMATIC FUNCTION INOP).(<P>TRANSFERRED TO MDDR #119418 IAW DDG 49-11-01-01A, CAT 'C', DUE DATE 30-OCT-2019. MAINT ACTION C/W. </P><P>LP 1097264 - M5: T/S APU BLEED IAW FIM 49-11 FT 958, NO FAULTS NOTED ON SYSTEM TEST OR LRU. MINI FLAG 15 SHOWN. REMOVED AND REPLACED FLOW SENSING MODULE AS PRECAUTIONARY IAW 49-53-08. OPS CHECK GOOD, NO FLUCTUATIONS NOTED AT THIS TIME. RAN ENGINES IAW 71-00-00, NO DEFECTS NOTED BEFORE OR AFTER ENGINE RUN, APU DID NOT FLUCTUATE. OPS CHECK NORMAL AT THIS TIME. MDDR 119418 CLEARED. PLACARDS REMOVED AND MCC NOTIFIED.</P>)