As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STARTED THE APU (NORMAL START) AND THE BLUE "MAINT" LIGHT ILLUMINATED. PERFORMED APU BITE TEST FOUND MSG 49 91227 LOW OIL QTY. OPENED APU ACCESS DOOR PERFORMED GVI OF APU FOR OIL LEAKS NONE FOUND. INSPECTED TAILPIPE FOR STREAKING NONE FOUND. APU OIL ADD 2.0 QUARTS.