The ECM monitors the internal fuel pressure of the common rail using the fuel pressure sensor, and controls the suction control valve to regulate the common rail pressure to the target pressure determined by the ECM. The pressure sensor is a semiconductor that varies its electrical resistance when pressure is applied to its silicon chip. This sensor outputs a voltage in proportion to the common rail fuel pressure.

The accelerator pedal position sensor is mounted on the accelerator pedal and detects the opening angle of the accelerator pedal. Since this sensor is electronically controlled with Hall-effect elements, accurate control and reliability can be obtained. It has 2 sensors to detect the accelerator position and a malfunction of the accelerator position sensor.

The fuel temperature sensor monitors the fuel temperature. The fuel temperature sensor has a thermistor that varies its resistance depending on the fuel temperature. When the fuel temperature is low, the resistance of the thermistor is high. When the temperature is high, the resistance is low. The variations of resistance are communicated to the ECM as changes of voltage (see Fig. 1).

The fuel temperature sensor monitors the fuel temperature. The fuel temperature sensor has a thermistor that varies its resistance depending on the fuel temperature. When the fuel temperature is low, the resistance of the thermistor is high. When the temperature is high, the resistance is low. The variations of resistance are communicated to the ECM as changes of voltage (see Fig. 1).

The exhaust fuel addition injector is mounted on the exhaust port of the cylinder head, and low pressure is provided to the injector by the feed pump in the supply pump. This injector adds fuel by a control signal from the ECM.

This injector is used for two different controls: DPNR catalyst regeneration and nitrogen oxides (NOx) reduction.

Under the DPNR catalyst regeneration control, the injector adds fuel to raise a catalyst temperature.

In order to detect abnormality in the DPNR (*3) catalytic converter, the ECM monitors an exhaust gas temperature as well as a differential pressure of the exhaust gas. For monitoring the differential pressure, the ECM compares the up-and downstream pressure of the DPNR catalytic converter. If the difference between the pressure is large, the ECM determines that the DPNR has become contaminated or is deteriorated, and illuminates the MIL.

The throttle position sensor is mounted on the diesel throttle body and detects the opening angle of the throttle valve. This sensor is an electronic sensor and uses Hall-effect elements.

The ECM determines the vehicle's driving conditions from the signals input to its VLU terminal. The data is one of the inputs used for EGR control, etc.

The ECM reduces injector operation speed and applied voltage to the injector to reduce the sound it produces during idling. To do this, the ECM outputs applied voltage switching signals to terminal IJEN of the EDU from terminal IDLO of the ECM.

A thermistor is built into the Engine Coolant Temperature (ECT) sensor and it changes its resistance value according to the engine coolant temperature.

The structure of the sensor and connection to the ECM is the same as the intake air temperature sensor.

The ECM determines the battery level according to the voltage of the BATT terminal while the engine is running (not cranking).