As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE ACCOMPLISHING TASK CARD N8349002 (APU GENERAL VISUAL INSPECTIONS) FOUND RED BUTTON ON THE APU OIL FILTER INDICATOR EXTENDED. GROUNDED - YES. REMOVED AND REPLACED LUBE FILTER ELEMENT PER B737-800 AMM 49-91-12, LEAK CHK GOOD, OK FOR SERVICE.