ECD SYSTEM SYSTEM DESCRIPTION


  1. ENGINE CONTROL SYSTEM

    B0024FGC01
    *1 ECM *2 Fuel Supply Pump Assembly
    *3 Pre-stroke Control Valve *4 Fuel Pressure Sensor
    *5 Common Rail Assembly *6 Pressure Discharge Valve
    *7 Glow Plug Controller *8 Intercooler
    *9 Intake Air Temperature Sensor (Turbo) *10 Mass Air Flow Meter Sub-assembly
    *11 Intake Air Temperature Sensor (Built Into Mass Air Flow Meter Sub-assembly) *12 EGR Cooler Sub-assembly
    *13 Vacuum Switching Valve Assembly (for EGR Bypass Valve) *14 Injector Assembly
    *15 Electric EGR Control Valve Assembly *16 Turbocharger Sub-assembly
    *17 Turbocharger Nozzle Vane Control Actuator *18 Camshaft Position Sensor
    *19 Glow Plug *20 Manifold Absolute Pressure Sensor
    *21 Diesel Throttle Body Assembly *22 Engine Coolant Temperature Sensor
    *23 Crankshaft Position Sensor *24 Accelerator Pedal Position Sensor
    *25 Atmospheric Pressure Sensor - -

  2. COMMON RAIL SYSTEM DESCRIPTION


    1. Common rail system:

      The common rail system uses high-pressure fuel for improved fuel economy. This system also provides robust engine power while suppressing engine vibration and noise.

      This system stores fuel in the common rail, which has been pressurized and supplied by the fuel supply pump assembly. By storing fuel at high-pressure, the common rail system can provide fuel at stable fuel injection pressures, regardless of engine speed or engine load.

      The ECM provides an electric current to the solenoid valve in each injector assembly to regulate the fuel injection timing and volume. The ECM also monitors the internal fuel pressure of the common rail using the fuel pressure sensor. The ECM causes the fuel supply pump assembly to supply the fuel necessary to obtain the target fuel pressure.

      In addition, this system uses a solenoid valve inside each injector assembly to open and close the fuel passages. Therefore, both fuel injection time and fuel injection volume can be precisely regulated by the ECM.

      The common rail system allows a multi stage fuel injection process. In order to soften combustion shock, this system performs "pilot-injection" prior to the "main-injection". This helps to reduce engine vibration and noise.

      B0026I2C02
      *1 Fuel Pressure Sensor *2 Common Rail Assembly
      *3 Pressure Discharge Valve *4 Fuel Supply Pump Assembly
      *5 Pre-stroke Control Valve *6 Injector Assembly
      *7 ECM *8 Fuel Filter Element Assembly
      *9 Fuel Tank Assembly *10 Crankshaft Position Sensor
      *11 Camshaft Position Sensor - -
      B0024II High Pressure Fuel B0068O0 Return Fuel
      B0068CQ Suction Fuel - -

      Tech Tips

      If there is a problem with a fuel return pipe, as bleeding air from the fuel system may not be able to be performed properly in certain instances, such as after replacing an injector assembly, etc., the engine startability may deteriorate.

    2. Common rail system components:

      Component Description
      Common rail assembly Stores high-pressure fuel produced by supply pump
      Fuel supply pump assembly

      • Operated by crankshaft via timing chain

      • Supplies high-pressure fuel to common rail
      Injector assembly Injects fuel to combustion chamber based on signals from ECM
      Fuel pressure sensor Monitors internal fuel pressure of common rail and sends signals to ECM
      Pressure discharge valve Based on signals from ECM, opens valve when sudden deceleration occurs, or when ignition switch is off to prevent fuel pressure from becoming too high
      Pre-stroke control valve Based on signals from ECM, adjusts fuel volume supplied to common rail and regulates internal fuel pressure
      Check valve Keeps pressure that discharges from injector

    3. Diagnostic trouble code (DTC) table for the common rail system:

      Tech Tips

      This table indicates typical DTC combinations for each malfunction occurrence.

      Trouble Area Malfunction DTC No.
      Injector assembly Open or short in injector circuit P0093*, P0201, P0202, P0203, P0204, P062D
      Stuck open P0093
      Stuck closed P0301, P0302, P0303, P0304
      Fuel pressure sensor Open or short in fuel pressure sensor circuit or pressure sensor output fixed P0087, P0190, P0191, P0192, P0193
      Pressure discharge valve Open or short in pressure discharge valve circuit P0088*, P0093*, P1229*, P1271, P1272
      Stuck open P0093
      Stuck closed P0088*, P1272
      Pre-stroke control valve Open or short in pre-stroke control valve circuit P0627, P1229, P0088*
      Stuck open P0088*, P1229
      Common rail system (Fuel system) Fuel leaks in high-pressure area P0093

      *: There may be no DTC output depending on the condition of the malfunction.

    4. Diagnostic trouble code description for the common rail system:

      DTC No. Description
      P0087 Fuel pressure sensor output does not change
      P0088

      Internal fuel pressure too high (240000 kPa [2447 kgf/cm2, 34800 psi] or more)
      P0093 Fuel leaks in high-pressure areas
      P0190 Open or short in fuel pressure sensor circuit (output voltage is too low or too high)
      P0192 Open or short in fuel pressure sensor circuit (output voltage is too low)
      P0193 Open or short in fuel pressure sensor circuit (output voltage is too high)
      P0201 Open or short in No. 1 injector circuit
      P0202 Open or short in No. 2 injector circuit
      P0203 Open or short in No. 3 injector circuit
      P0204 Open or short in No. 4 injector circuit
      P0301 Cylinder 1 misfire detected
      P0302 Cylinder 2 misfire detected
      P0303 Cylinder 3 misfire detected
      P0304 Cylinder 4 misfire detected
      P0627 Open or short in pre-stroke control valve circuit
      P062D ECM internal error
      P1229 Fuel over-feed
      P1271 Open or short in pressure discharge valve circuit
      P1272 Pressure discharge valve stuck close

  3. FUEL SUPPLY PUMP OPERATION SYSTEM DESCRIPTION


    1. When the cam rotates the roller is pushed up, and in turn the plunger is pushed upward as well. When the plunger is not pushed up by the cam, it is pushed back down by the spring.

      B0027QHC01
      *1 Pre-stroke Control Valve *2 Plunger
      *3 Spring *4 Shoe
      *5 Roller *6 Double Cam

    2. The ECM controls the timing of the pre-stroke control valve opening to regulate the fuel quantity. Consequently, the fuel pressure in the common rail is controlled to the target injection pressure.

    3. The longer the pre-stroke control valve remains open, the quantity of pressure-fed strokes will decrease, as well as the fuel discharge quantity.

    4. Pumping will start when the fuel pressure has become higher than the common rail pressure.

      B0027JZC01
      *a Return Fuel - -

    5. The less time the pre-stroke control valve remains open, the quantity of pressure-fed strokes will increase, as well as the fuel discharge quantity.

    6. Pumping will start when the fuel pressure has become higher than the common rail pressure.

      B0024A5