As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER LANDING "MAINT" ILLUMINATES DURING TAXI. GROUNDED - YES. FOUND FAULT CODE 36-12020 FAN AIR MODULATING VALVE NOT IN COMMANDED POSITION. ACCOMPLISHED B737-9 IFIM 36-12-00-810-801 LRU TEST PASS NO FAULTS FOUND AFTER TEST. INTERMITTENT FAULT.