As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER ENGINE START- RIGHT PACK LIGHT ON - FOLLOWED QRH AFTER MC RESET. IS WENT OUT. GROUNDED - YES. PACK/ZONE TEMP CONTROLLER BITE TEST DONE ON RH SIDE: THIS PACK TCV SHOWED FAULTING ON PREVIOUS FLIGHT. FAULT RESETS REF B737-800 AMM 21-61-00-806-002.