As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TECH SERVICES REQUEST REPLACEMENT OF THE #1(LEFT)V18 FLOW CONTROL VALVE DUE TO REPORT LEFT PACK CYCLING FROM HIGH TO LOW FLOW. GROUNDED - YES. REMOVED AND REPLACED LEFT FLOW CONTROL AND SHUTOFF VALVE REF B737-900 AMM 21-51-01 OPS CHECK NORMAL.