As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RIGHT PACK LIGHT ILLUMINATED AT GATE BOTH PACKS IN AUTO, ISOLATION VALVE IN OPEN ALL THREE ZONE CONTROL IN AUTO, ATTEMPTED QRC RESET, UNABLE TO CLEAR. ACFT GROUNDED. IAW FIM TASK 21-62 TASK 831, FOUND NR 2 TEMP CONTROL TCV FAULT. ACCOMPLISHED BITE & RESET FAULT. OPS NORMAL. OK FOR SERVICE.