As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAXI IN APU FAULT LIGHT ILLUMINATED AFTER START ATTEMPT. GROUNDED - YES. REMOVED AND REPLACED STARTER CONVERTER UNIT SERIES 7 IAW B737-900 AMM 49-41-61/401. GROUND VERIFICATION TEST IS GOOD. APU STARTS AND HOLDS LOAD WITH EXTERNAL AND BATTERY. PERFORMED OPERATIONAL TEST OF THE STARTER GEN IAW AMM 49-41-21/401. OPS CHECKS GOOD. SGU LEAK CHECKS GOOD REF AMM 49-41-21-400-801 STEP 3I(4).