Group 23 EMS 2 Design and function
Coolant level sensor (1)
The sensor is located in the expansion tank.
It’s purpose is to detect if the coolant level in the cool-
ing system (expansion tank) becomes too low. The
sensor is a magnetically sensitive switch. A float lo-
cated around the sensor affects the switch differently
depending on the coolant level. A alarm signal is sent
when the coolant level is too low.
Coolant temperature sensor (16)
The sensor is located in the left rear part of the cylin-
The sensor senses the coolant temperature and
sends the information to the control unit. The sensor
comprises a non-linear resistor, where the resistance
is dependant on the temperature of the resistor body.
The resistance drops as temperature rises.
Charge air pressure/charge air
The charge air pressure and temperature are mea-
sured via a combined sensor positioned on the inlet
The charge air pressure sensor measures absolute
pressure, which is the sum of charge air pressure and
atmospheric pressure. The sensor supplies the control
unit with a voltage signal proportional to the absolute
pressure. The sensor receives a reference signal of 5
Volts from the control unit.
The charge air temperature sensor comprises a non-
linear resistor, where the resistance is dependant on
the temperature of the resistor body. The resistance
drops as temperature rises.
Fuel pressure sensor (10)
The sensor is located on the left side of the engine,
mounted on the fuel filter bracket.
The pressure signal is a voltage signal proportional to
the pressure. The sensor reference voltage is 5 Volts.