As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
2 ATTEMPTS AT STARTING APU RESULTED IN THE FAULT LIGHT ILLUMINATING BOTH TIMES. GROUNDED-YES. FOUND APU TO HAVE NO IGNITION. REPLACED IGNITION UNIT, IAW B737-800 AMM TASK 49-41-31-000-801 AND 49-41-31-400-801. REPLACED IGNITER PLUG LEAD, IAW AMM TASK 49-41-52-000-801 AND 49-41-52-400-801. REPLACED IGNITER PLUG, IAW AMM TASK 49-41-51-000-801 AND 49-41-51-400-801. OPERATIONS CHECK GOOD, IAW AMM TASK 49-11-00-860-801.