As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN)BEFORE TAKEOFF, DURING GROUND RUNS THE TWO WARNING LIGHTS "VACUUM PUMP INOP." LIGHT UP TOGETHER. INSPECTION FOUND THE RIGHT HAND PUMP SEIZED AND THE ONEWAY VALVE HALF BLOCKED BY A PIECE OF RUBBER. SOU RCE OF THE RUBBER IS UNKNOWN. FILTERS CHECKED AND CHANGED.