As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYSTEM: LEFT ENG BLEED TRIPPED JUST BEFORE TOP OF CRUISE. ACCOMPLISHED HEALTH CHECK ON NR 1 ENGINE IAW B737-800 M/M 36-11-00 FOUND PRECOOLER VALVE AT FAULT REMOVED AND REPLACED NR 1 ENGINE PRECOOLER VALVE IAW B737-800 M/M 36-12-02, OPS CHECK NORMAL.