As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SITTING AT THE GATE WITH APU BLLED AND BOTH PACKS OFF, SUDDENLY GOT L PACK LIGHT ILLUMINATED, AND WOULD NOT RESET WITH MASTER CAUTION RESET. THIS PACK ALREADY HAS MEL 21-32B APPLIED. GROUNDED - YES. ACCOMPLISHED PACK TEMP CONTROL BITE TEST AND FOUND TCV FAULT. CLEARED FAULT. RAN LH PACK FOR 10 MINUTES. NO FAULTS NOTED. OPS CHECK GOOD. LH PACK LIGHT EXTINGUISHED. GROUND VERIFICATION SUCCESSFUL. SEAMC JOEY NOTIFIED. NON ASA# YUJR093Y.