Hitachi ZAXIS 120-6 class Operator's Manual page 106

 Fuel Sensor Error Display
If the fuel sensor is faulty, the color of the fuel mark changes
and the needle disappears. If the harness between the
fuel sensor and the controller unit is broken, the needle
disappears.
 Coolant Temperature Sensor Error Display
If the coolant temperature sensor is faulty, the color of the
temperature mark changes and the needle disappears.
If the harness between the temperature sensor and the
controller unit is broken, the needle disappears.
 Engine Speed Control Display
Engine warming-up operation due to low coolant
temperature. The engine speed can not be changed during
this operation. While the engine speed is controlled, mark
(2) is displayed on monitor (1). When the control completes,
mark (2) goes OFF and the engine speed becomes
adjustable.
OPERATOR'S STATION
Coolant Temperature
Sensor Error Display
1-24
2
Fuel Sensor Error Display
MDC1-01-024
1
MDC1-01-355