As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU FAULT AND SHUTDOWN ON GROUND AFTER LANDING. GROUNDED - YES. ACCOMPLISHED B737-9 IFIM TASK 49-40-00-810-818 STEPS A.-C.(5)(C) AND IFIM TASK 49-40-00-810-805 STEPS A.-C.(5)(C). NO DEBRIS ON MAGNETIC PLUG, APU ROTATES FREELY, WIRING CHECK OK. REPLACED STARTER GENERATOR UNIT. OPS/LEAK CHECK OK. REF. B737-9 AMM 49-41-21-400-8011.