As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI IN, APU START ATTEMPTED, FAULT LIGHT ILLUMINATED. APU DID NOT START. QRM COMPLETED. APU FAILED TO START ON SUBSEQUENT RESTART ATTEMPTS. GROUNDED - YES. REMOVED AND REPLACED APU STARTER-GENERATOR IAW B737-800 AMM 49-41-21. OPS CK AND LEAK CK GOOD. NO DEFECTS NOTED.