As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI OUT LEFT HAND PACK INOP ILLUMINATED. ACFT RETURNED TO THE GATE (BTB) AND MTX GROUNDED A/C. MTX DEFERRED LH PACK IAW MEL ABX-21-51-1-1 AND RETURNED A/C TO SERVICE. NEXT LEG, MTX REPLACED ZONE TEMP CONTROLLER IAW AMM 21-61-03. OPS CHECK GOOD. THIS CLEARS D.I. REACTIVATION C/W. ACFT REMAINS NO ETOPS. PLACARDS REMOVED REF. LOG PAGE 39433-83/3.