The EGR system recirculates exhaust gases. The recirculated gas mingles with the intake air so that the EGR system can slow combustion speed and keep the combustion temperature down. This helps reduce NOx emissions.

In order to increase EGR circulation efficiency, the ECM adjusts the lift amount of the EGR valve and the throttle valve angle.

To detect atmospheric pressure, the built-in atmospheric pressure sensor in the ECM is used for the common rail system. Following the changes in the atmospheric pressure, the ECM corrects the injection volume, timing and duration, and adjusts the common rail internal fuel pressure in order to optimize engine combustion.

The camshaft position sensor (G signal) consists of a magnet, iron core and pickup coil.

The G signal plate (timing sprocket) has one tooth on its outer circumference and is installed on the camshaft timing chain gear. When the timing gear rotates, the protrusion on the signal plate and the air gap on the pickup coil change, causing fluctuations in the magnetic field that generate a voltage in the pickup coil.

Refer to DTC P2120 ().

Disconnect the crankshaft position sensor connector.

Connect the intelligent tester to the DLC3.

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).

Refer to DTC P0180 ().

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 pedal position sensor.

If the idle speed drops or becomes unstable when the engine is running at idle with a low load, this DTC is stored. This DTC is also stored if the vehicle runs out of fuel. Be sure to check whether there is enough fuel in the fuel tank before inspection.