As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
"MAINT" LIGHT ILLUMINATED. GROUNDED - YES. INTERROGATED FAULTS AND FOUND FAULT 21-65151, CONTROL CABIN TRIM VALVE SIGNAL IS OUT OF RANGE OR VALVE IS NOT IN COMMANDED POSITION. C/W B737-9 IFIM TASK 21-61-00. FAULT IS INTERMITTENT. MAINTENANCE LIGHT EXTINGUISHED. NO FURTHER DEFECTS NOTED.