As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED DUE TO THIS EVENT. ODOR EVENT WITH A STALE OR MUSTY ODOR THROUGHOUT THE PLANE, BUT MOSTLY TOWARD THE AFT. FOUND APU LUBE MODULE LEAKING FROM BASE, REMOVED AND REPLACED LUBE MODULE IAW AMM 49-91-45-000/400-003-A. LEAKS CHECK GOOD. RAN APU BLEED WITH PACKS ON, NO SMELL NOTED. COMPRESSOR WASH REQUIRED. NO LEAKS AT THIS TIME. APU PLACED ON MEL 49-10-01A. AIRCRAFT RETURNED TO SERVICE.