Hitachi ZW180 Technical Manual page 114

Engine Warning Indicator Control
Purpose: To light the engine warning indicator on
monitor unit in order to inform the engine
failure detected by ECM to the operator.
Operation:
1. When detecting the engine failure, ECM grounds
terminal #44. Therefore, terminal 2-21 of the
monitor unit is grounded.
2. When the monitor unit terminal is grounded, the
monitor unit lights the engine warning indicator.
Service Indicator
Engine Warning
Indicator
SYSTEM / ECM System
Monitor
Unit
Diode B
2-21
3. When the engine returns to normal conditions,
ECM deactivates the ground connection to
terminal #44. Therefore, terminal 2-21 of the
monitor unit is disconnected form the engine.
4. When terminal 2-21 of the monitor unit is
disconnected form the engine, the monitor unit
turns off the engine warning indicator.
NOTE: The monitor unit lights the service indicator
as well as the engine warning indicator.
T2-2-8
ECM
44
T4GD-02-02-008