As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FAULT AND SHUTDOWN ON ENGINE START. BITE CHECK OF APU ECU SHOWS NO FAULTS, APU SHUTDOWN OCCURRED ON ENGINE START WITH AIR DEMAND. FWD APU PNEU TO MCO PER MEL49-11-01C. ECU SHOWS NO FAULTS. REPLACED SCV AS PREVENTIVE MEASURE PE M/M. MOTORED ENG 2 TIMES CKS OK MCO AND PLACARD REMOVED.