ECD SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


    1. The main components of the engine control system are as follows:

      Component Outline Quantity Function
      ECM 32-bit CPU 1 The ECM effects overall control of the engine control system to suit the operating conditions of the engine in accordance with the signals provided by the sensors.
      Injector Driver DC/DC Converter 1 The injector driver is used to drive the injector assembly at high speeds. The injector driver has achieved high-speed driving under high fuel pressure conditions through the use of a DC/DC converter that provides a high voltage, quick-charging system.
      Turbo Pressure Sensor Semiconductor Silicon Chip Type 1 This sensor uses built-in semiconductors to detect the intake manifold pressure.
      Atmospheric Pressure Sensor Semiconductor Silicon Chip Type 1 This sensor, which is built into the ECM, uses semiconductors to detect the atmospheric pressure.
      Fuel Pressure Sensor Semiconductor Strain Gauge Type 1 This sensor uses built-in semiconductors to detect the internal pressure of the common-rail assembly.
      Pressure Discharge Valve Solenoid Type 1 The pressure discharge valve regulates the fuel pressure.
      Crank Position Sensor

      Pick-up Coil Type

      (Rotor Teeth/36-2)

      		 1 This sensor detects the engine speed and performs the cylinder identification.
      Camshaft Position Sensor (No. 2 Crank Position Sensor)

      Pick-up Coil Type

      (Rotor Teeth/5)

      		 1 This sensor performs the cylinder identification.

      Intake Air Temperature Sensor

      (Air Cleaner Outlet)

      		 Thermistor Type 1 This sensor detects the intake air temperature by means of an internal thermistor.
      Engine Coolant Temperature Sensor Thermistor Type 1 This sensor detects the engine coolant temperature by means of an internal thermistor.
      Fuel Temperature Sensor Thermistor Type 1 This sensor detects the fuel temperature in the supply pump assembly by means of an internal thermistor.
      Throttle Position Sensor Non-contact Type 1 This sensor detects the diesel throttle valve opening angle.
      Accelerator Pedal Sensor Assembly Non-contact Type 1 This sensor detects the amount of pedal effort applied to the accelerator pedal.
      Suction Control Valve (SCV) Linear Solenoid Valve 1 The SCV position is controlled by the signals from the ECM, and a fuel volume that suits the SCV position is drawn into the pumping portion (plunger portion).
      Injector Assembly 6-hole, Solenoid Type 4 The injector assembly injects the fuel to the combustion chamber in accordance with the ECM signals via the injector driver.

  2. SYSTEM CONTROL


    1. The engine control system has the following features. The ECM controls these systems:

      System Outline
      Fuel Injection Volume Control Based on the signals received from the sensors, the ECM determines the fuel injection volume in accordance with the engine condition.
      Fuel Injection Timing Control Based on the signals received from the sensors, the ECM determines the fuel injection timing in accordance with the engine condition.
      During Starting Control To facilitate startability, the ECM optimally controls the injection volume and injection timing during starting.
      Idle Speed Control The ECM determines the idle speed in accordance with the engine condition, and controls the fuel injection volume in order to maintain the target idle speed.
      Fuel Pressure Control Based on the signals received from the sensors, the ECM controls fuel pressure using the Suction Control Valve (SCV) and pressure discharge valve in accordance with engine operating conditions.
      Pilot Injection Control Based on the signals received from the sensors, the ECM determines pilot injection volume/timing and interval (between pilot injection and main injection) in accordance with the engine condition.
      Glow Plug Control The ECM controls the length of time for which the current is applied to the glow plug assemblies, in accordance with the engine coolant temperature.
      Diesel Throttle Control

      • Controls the diesel throttle valve opening angle in accordance with the engine condition.

      • Fully closes the diesel throttle valve in order to reduce the vibration when the engine is stopped.
      Air Conditioning Cut-off Control*1 By controlling the air conditioning compressor on or off in accordance with the engine condition, driveability is maintained.
      Engine Immobiliser*2 Prohibits fuel delivery and ignition if an attempt is made to start the engine with an invalid key.
      Brake Override System The driving torque is restricted when both the accelerator and brake pedals are depressed. (For the activation conditions and inspection method, refer to the Repair Manual.)
      Diagnosis When the ECM detects a malfunction, it diagnoses and memorizes the failed section.
      Fail-safe When the ECM detects a malfunction, it stops or controls the engine in accordance with the data already stored in the memory.

      • *1: Models with air conditioning system

      • *2: Models with engine immobiliser system