As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON STARTING ATTEMPT NR 1 N2 WHENT UP TO 6.5%. ATTEMPT NR 2 N2 ONLY GOT TO 4% ON NR 2 ENGINE. GROUNDED-YES. REMOVED & REPLACED NR 2 ENGINE STARTER/QUAD RING, REF B737-900 AMM 80-11-01, 80-11-0280-11-01. PERFORMED ENGINE RUN, REF AMM 71-00-00-700-801-F00 TEST NR 3A ENGINE START NORMAL.