As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN FLIGHT RECEIVED APU OIL TEMP CAUTION. RAN QRH, DIVERTED BACK. MSG DID NOT CLEAR. ON GND MANUALLY SHUTDOWN APU. CLEANED APU OIL TEMP CONNECTOR P13 & COMPLIED WITH OPERATIONS CHECK OF APU IAW AMM 49-91-25 & 49-10-01. APU OPERATIONS CHECKED GOOD. GEN 2 WAS ON MEL, CLEARED BY OPERATIONS CHECK.