As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING MASTER CAUTION RECALL AFTER STARTING MOTORS, L PACK LIGHT ILLUMINATED. LIGHT EXTINGUISHED WITH MASTER CAUTION RESET. GROUNDED - YES. REMOVED AND REPLACED LH PACK RAM AIR EXHAUST ACTUATOR (SRADA) REF B737-900 AMM 21-51-27/401. BITE TEST ON THE LEFT AND RIGHT PACK/ZONE TEMPERATURE CONTROLLERS AND CHECK/ADJUSTMENT OF THE RAM AIR EXHAUST ACTUATOR ALL CHECK GOOD.