jonnywalton
New User
Working on Hitachi EX120-2 early model looks like the 490E. Installed new motor Replaced wire harness and 2 new computer. On the pump speed, and angel sensor,throttle touch pad/ pump restate board and the engine will not start. When I un plug the new throttle stepping motor and wire the throttle to open and runs then the hydraulic pump destrokes and engine dies. The computes I replaced shows 490E on both I have DR EX scanner and trying to link computer and find the codes out ans nothing happens said bad connection. I am at last straw shows unit controller 424657 like EC controller and larger Relay 419199 only thing that I have not replaced. Any idea what I should doo John deere said that gray market machine and said good luck but the excavator came with 490 E computers and wire harness covers ex120-2 and ex120-3 and john deere said the 120-3 are the 490E and the 120-2 are the early generation.
