As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE PERFORMING ASA TASK CARD N8436001 GROUND WING TAI SOLENOID VALVE TEST STEP (2)(C(2) PRECOOLER CONTROL VALVE WOULD NOT CLOSE. GROUNDED - YES. CHECKED ALL LINES GOING TO PRECOOLER CONTROL VALVE TO THE PRECOOLER CONTROL VALVE SENSOR NO LEAK NOTED FOUND. REMOVED AND REPLACED PRECOOLER CONTROL VALVE SENSOR IN REF TO B737-900 AMM 36-12-03-400-801 LEAK CK GOOD.