While the engine is being cranked, positive battery voltage is applied to terminal STA of the ECM.

If the ECM detects the starter control (STA) signal while the vehicle is being driven, it determines that there is a malfunction in the STA circuit. The ECM then illuminates the MIL and stores the DTC.

This monitor runs when the vehicle has been driven at 20 km/h (12.4 mph) or more for more than 20 seconds.

Connect the intelligent tester to the DLC3.

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 internal pressure to the target pressure. The pressure sensor is a semiconductor that varies electrical resistance when pressure is applied to its silicon chip. This sensor outputs the voltage in proportion to the internal fuel pressure.

The battery supplies electricity to the ECM even when the ignition switch is off. This power allows the ECM to store data such as DTC history, freeze frame data and fuel trim values. If the battery voltage falls below a minimum level, the ECM memory is cleared and the ECM determines that there is a malfunction in the power supply circuit. When the engine is next started, the ECM illuminates the MIL and stores the DTC.

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

The stop light switch is a duplex system that transmits two signals: STP and ST1-. These two signals are used by the ECM to monitor whether or not the brake system is working properly. If the signals, which indicate that the brake pedal is being depressed and released, are detected simultaneously, the ECM interprets this as a malfunction in the stop light switch and sets the DTC.

Drive the vehicle and check whether the operation of the speedometer in the combination meter is normal.

The ECM opens and closes the throttle valve using a rotary solenoid type actuator. Due to the opening and closing of the valve, the exhaust gas recirculation volume can be properly controlled. Also, engine vibration and noise will be reduced by closing the valve when the engine is stopped.

The EGR valve position sensor is mounted on the EGR valve and used for detecting the lift amount of the valve. The lift amount detected by the sensor is provided to the ECM as feedback. The ECM then regulates the lift amount of the valve in accordance with engine running conditions.

These DTCs indicates that the DC motor of the turbocharger is malfunctioning. The ECM monitors the DC motor current to detect an open or short in the DC motor circuit. If the current meets the criteria, the ECM sets a DTC and illuminates the MIL immediately.