Hitachi ZW180, Technical Manual

Page: 114 / 374

SYSTEM / ECM System
T2-2-8
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.
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.
T4GD-02-02-008
ECM Monitor
Unit
Diode B
44
2-21
Service Indicator
Engine Warning
Indicator