As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON PUSHING MASTER CAUTION DURING DESCENT CHECKLIST "SPEED TRIM FAIL" LIGHT ILLUMINATED ALONG WITH FLT CONT MASTER CAUTION LIGHT. LIGHT EXTINGUISHES UPON RESET OF MASTER CAUTION SYSTEM. GROUNDED - YES. RAN B737-9 FIM 22-11-00-810-D71, BITE TESTS PASSED, FAULT CLEARED.