As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ENGINE START, APU WOULD ONLY MAKE 21 PSI DUCT PRESSURE. START WAS NORMAL.(<P>PERFORMED #1 AND #2 ENGINE RUNS (INDEPENDENT) WITH APU, BOTH ENGINE STARTS NORMAL. NO FAULTS, APU PRESSURE +30 PSI, REF AMM 71-00-00/501. OPS CHECK GOOD.</P>)