As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE OPERATING THE APU WITH THE NR 2 GENERATOR PLACARDED INOPERATIVE, THE APU SHUTDOWN CLIMBING THROUGH 3,000 FEET. RESTART ATTEMPT WAS UNSUCCESSFUL. THE AIRCRAFT WAS DIVERTED TO IAH WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE TROUBLESHOT TO A FAILED STARTER. THE APU STARTER WAS REMOVED AND REPLACED. APU ELECTRICAL AND PNEUMATIC OPERATION CHECKED GOOD.