As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER PUSHBACK & ENG START ON RECALL # 2 PACK LIGHT ILLUMINATED, RESETS ON MASTER CAUTION PUSH. RAN QRH. GROUNDED - YES. RAM AIR ACTUATOR FAULT ON #2 ZONE TEMP CONTROLLER. RAN PACK TEMP CONTROLLER BITE TEST FAULT NO LONGER PRESENT SUSPECT INTERMITTENT FAULT REFB737-800 FIM 21-62 TASKS 801 AND 836.