As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI NO RT ENG BLEED AIR AVAILABLE, RTB. PRV CONTROLLER REPLACED BUT FOUND INOP ON FIT. LOAN ITEM OBTAINED FROM LUFTHANSA. FITTED IAW AMM 36-11-19-404-016-001, ENGINE RUN. PERFORMED AND OPS OK. ETOPS CATEGORY 'E': PROBLEMS WITH SYSTEMS CRITICAL TO ETOPS.