As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LT HYD QTY DECREASED TO ZERO AND SYSTEM PRESS LGT ILLUM, EICAS MSG L HYD SYS PRESS DISPLAYED. IAW AMM 29-11-17 WAS REPLACED THE DIFFERENCIAL PRESSURE INDICATOR LT AND ENGINE DRIVEN PUMP WAS REPLACED. LT DIFF PRESS INDICATOR S/N OFF SIN P/N OFF SIN P/N ON 7686631 SN ON 02326.