What was found
DURING AFTER START CHECK LIST, C HYD SYS PRESS DISCRETE LIGHT AND EICAS MSG DISPLAYED. QRH PROCEDURE DID NOT FIX THE ISSUE.AC/ REURNED TO THE GATE (BTB) AND MTX GROUNDED A/C, MTX THEN PERFORMED OPS TEST PER AMM 29-11-00, OPS TEST GOOD .MTX THEN RETURNED A/C TO SERVICE AND A/C DEPARTED.