What was found
TROUBLE SHOOTING RT PACK MSG 21-23004. AHM PROGRAM IS DETECTING REPEAT FAULT MSG 21-23004 FOR RT PACK DIFFERENTIAL PRESSURE MISCOMPARE FAULT. RT PACK UPPER FCV AND FLOW SENSOR MODULE PREVIOUSLY REPLACED. NEED TO REPLACE THE RT CABIN TEMP CONTROLLER CTC-R (M21632) PCN 566-9016, IAW MM21-61-01. AS FAULT HAS PREVIOUSLY BEEN DETECTED ON TAXI OUT, NEED TO RUN BOTH ENGS AND USE ENGINE BLEED AIR AS SOURCE TO OP CK PACKS & CONFIRM NO FAULTS EXIST. REPLACED CTC REF MM. RAN PACKS OFF ENGINES ON START OPERATED NORMAL. NO MSG.