As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYSTEM, L ENG PRV WARNING CAME ON SEVERAL TIMES DURING DESCENT FRM FL 380. TROUBLESHOT PER FIM 36-10-00 FIG 123. FOUND LOOSE SENSE LINE TO PRE-COOLER. TIGHTENED LINE, RAN ENGINE AND PERFORMED OPERATIONAL TEST OF PRV PER AMM 36-11-18/501. OPERATIONAL CHECK GOOD.