As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT ENGINE BLEED OFF EICAS MESSAGE. AIRCRAFT BACK TO BLOCK AND GROUNDED BY MAINTENANCE. REMOVED AND REPLACED LEFT ENGINE PRSOV IAW AMM 36-11-09. PERFORMED THE AIR SUPPLY BITE TEST IAW AMM 36-23-00. PERFORMED ENGINE RUN IAW AMM 71-00-00. NO DEFECTS FOUND, OPS CHECK GOOD. AIRCRAFT RELEASED.