What was found
PDIS 603 36-22 9517 28DEC21 KIX FACT U IN CRUISE AT FL310, 1:40 INTO FLIGHT, RECEIVED AIR SYS 3 OFF ALERT, SYSTEM 3 PRESSURE INDICATED 0. BLEED AIR 3 PRESS AND OFF LIGHTS ALONG WITH MANF LIGHT WHICH REMAINED ON FOR APPROXIMATELY 1 MINUTE BEFORE EXTINGUISHING (MANF ONLY.) AT MOC RECOMMENDATION, CYCLED AIR SYSTEM TO MANUAL AND BACK TO AUTO WITH NO CHANGE IN SYSTEM STATUS. WAS TOLD A/C WAS REPORTING A TEMP SENSOR OVER TEMP CONDITION, SO THE CONSENSUS WAS TO NOT ATTEMPT ANY FURTHER TROUBLESHOOTING. SHGN 28DEC21 04:50 KIX U FACT 28DEC21 09:15 KIX U CONTINUITY CHK WAS GOOD WITH NO SHORT TO GND ON D1-153 SENSING ELEMENT PER WDM36-23-01. REMOVED AND REPLACED D1-153 SENSING ELEMENT PRECAUTIONALLY PER AMM36-23-07-4. FOLLOWED FIM36-23-06(MFC PNEU 3 OUT), REMOVED AND REPLACED MFC PER AMM36-23-01-4. PERFORMED HIGH PWR ENG RUN-UP(10 MIN) AND NO DEFECT FOUND PER AMM71-00-00-5-1. PERFORMED MFC R-T-S TEST PASSED 36-23-01-5. A/C OK FOR SERVICE.