As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FWD EQUIPMENT VALVE CAUTION MESSAGE ON TAXI OUT. DID NOT CLEAR IN 30 SECONDS, CLEARED AFTER 4:30 SECONDS. TRANSFERRED TO MDDR 117248 IAW MEL 21-58-07-02-01, CAT "C", DUE 13-SEP-2019. MX ACTION C/W, PROCEDURE #2. LP 1066756 - M2: PERFORMED FIM 21-58 FT 899, FOUND MANIFOLD INTERCONNECT VALVE TO BE FAULTING. REMOVED AND REPLACED MANIFOLD INTERCONNECT VALVE IAW 21-58-01. OPS CHECK NORMAL AT THIS TIME. THIS CLEARS MDDR #117248. PLACARDS REMOVED AND MCC NOTIFIED.