Hitachi ZAXIS 120-6 class Operator's Manual page 474

Engine Speed
Problem
Even if operating the engine control
dial, the engine speed does not
change.
Work mode does not change.
Auto-idle is inoperable or not released. Faulty pressure sensor.
Pump Control
Problem
Front attachment and/or travel speed
is slow.
Others
The machine may have a noise, excessive vibration, and abnormal smell when any trouble occurs.
Always beware of the machine conditions during operation.
TROUBLESHOOTING
Cause
Blown fuse
Faulty engine control dial
Poor contact in connector
Damaged wire harness (between EC dial and
MC, or MC and ECM)
Faulty controller (MC, ECM)
Performing manual regeneration
Faulty mode switch
Poor contact in connector
Damaged wire harness (between MC and
monitor)
Faulty controller (MC)
Faulty solenoid valve
Poor contact in connector
Damaged wire harness
Faulty controller.
Performing manual regeneration
Cause
Blown control fuse
Poor contact in connector
Damaged wire harness
Faulty controller.
Faulty pump solenoid valve.
Faulty pressure sensor.
11-8
Replace
* Replace
* Repair or replace
* Repair
* Replace
(Normal control)
* Replace
* Repair or replace
* Repair
* Replace
* Repair or replace
* Replace
* Repair or replace
* Repair
* Replace
(Normal control)
Items with * mark: Consult your authorized dealer.
Replace
* Repair or replace
* Repair
* Replace
* Replace
* Replace
Items with * mark: Consult your authorized dealer.
Solution
Solution