ECD SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


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

      Component Function
      ECM The ECM performs overall control of the engine control system to suit the operating conditions of the engine in accordance with the signals provided by the sensors.
      Crank Position Sensor This sensor detects the engine speed and performs cylinder identification.
      Cam Position Sensor (Crank Position Sensor) This sensor performs cylinder identification.
      Fuel Pressure Sensor This sensor uses built-in semiconductors to detect the internal pressure of the common-rail.
      Intake Mass Air Flow Meter Sub-assembly This sensor uses a built-in silicon chip to directly detect the intake air mass.
      Intake Air Temperature Sensor This sensor detects the intake air temperature past the intercooler.
      Diesel Throttle Body Assembly Throttle Position Sensor This sensor detects the diesel throttle valve opening angle.
      Throttle Motor Controls the throttle valve opening according to signals from the ECM.
      Turbo Pressure Sensor This sensor uses built-in semiconductors to detect the intake manifold pressure.
      Turbocharger Sub-assembly Actuator This sensor detects the nozzle vane position.
      Controls the variable nozzle vane according to signals from the ECM.
      Engine Coolant Temperature Sensor This sensor detects the engine coolant temperature by means of an internal thermistor.
      Glow Plug Controller The glow plug controller controls the length of time for which the current is applied to the glow plug assemblies in accordance with the ECM signal.
      Injector Assembly The injector injects the fuel to the combustion chamber in accordance with the ECM signals.
      Pre-stroke Control Valve Assembly Regulates the pre-stroke quantity according to signals from the ECM.
      Pressure Discharge Valve The pressure discharge valve regulates the fuel pressure.
      EGR Valve Position Sensor Detects the EGR valve position and sends signals to the ECM.

  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 pre-stroke control 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 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 vibrations when the engine is stopped.
      Turbocharger Control Based on the signals received from the sensors, the ECM controls the actuator in accordance with the engine condition.
      EGR System

        Models without EGR Cooler

      • Based on the signals received from the sensors, the ECM determines the EGR volume via the electric EGR control valve assembly in accordance with the engine condition.


        Models with EGR Cooler

      • Based on the signals received from the sensors, the ECM determines the EGR volume via the electric EGR control valve assembly and No. 2 EGR valve assembly in accordance with the engine condition.

      For details, see the EMISSION CONTROL SYSTEM section.
      Air Conditioning Cut-off Control By controlling the air conditioning compressor on or off in accordance with the engine condition, driveability is maintained.
      Immobiliser System Prohibits fuel injection if an attempt is made to start the engine with an invalid ignition 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.