SFI SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


    1. The main components of the 1ZR-FE engine control system are as follows.

      Components Outline Quantity Function
      ECM 32-bit CPU 1 Optimally controls the engine control system to suit the operating conditions of the engine in accordance with the signals provided by the sensors.
      Crank Position Sensor (Rotor Teeth) Pick-up Coil Type [36 - 2] 1 Detects the engine speed and the crank angle.
      Camshaft Position Sensor (Rotor Teeth) Magnetic Resistance Element (MRE) Type [3] 2 Performs cylinder identification and detects the VVT angle.
      Knock Control Sensor Built-in Piezoelectric Element Type (Flat Type) 1 Detects an occurrence of engine knocking indirectly from the vibration of the cylinder block caused by the occurrence of engine knocking.
      Mass Air Flow Meter Sub-assembly Hot-wire Type 1 Uses a built-in hot-wire to directly detect the intake air mass.
      Throttle Body Assembly Throttle Position Sensor Non-contact Type 1 Detects the throttle valve opening angle.
      Heated Oxygen Sensor Type with Heater (Cup Type) 1 Detects the oxygen concentration in the exhaust emissions by measuring the electromotive force generated in the sensor itself.
      Air Fuel Ratio Sensor Type with Heater (Planar Type) 1
      Accelerator Pedal Sensor Assembly Non-contact Type 1 Detects the amount of pedal effort applied to the accelerator pedal.
      Fuel Injector Assembly 12-hole Type 4 Is an electromagnetically-operated nozzle which injects fuel in accordance with the signals from the ECM.
      Engine Coolant Temperature Sensor Thermistor Type 1 Detects the water temperature by means of an internal thermistor.

  2. SYSTEM CONTROL


    1. The engine control system of the 1ZR-FE engine has the following systems.

      System Outline
      Sequential Multiport Fuel Injection (SFI)

      • An L-type SFI system detects the air mass with a hot-wire type mass air flow meter sub-assembly.

      • The fuel injection system is a sequential multiport fuel injection system.
      Electronic Spark Advance (ESA) Ignition timing is determined by the ECM based on signals from various sensors. The ECM corrects ignition timing in response to engine knocking.
      Electronic Throttle Control System-intelligent (ETCS-i) Optimally controls the throttle valve opening in accordance with the amount of accelerator pedal effort, the throttle valve opening control request from the ECM, and the condition of the engine and the vehicle.
      Dual Variable Valve Timing-intelligent (Dual VVT-i) Regulates operation of the intake and exhaust camshafts to ensure an optimal valve timing in accordance with engine operating conditions.
      Fuel Pump Control

      • Fuel pump operation is controlled by signals from the ECM.

      • The fuel pump is stopped when any of the Supplemental Restraint System (SRS) airbags are deployed.
      Cooling Fan Control The ECM steplessly controls the speed of the fan via the cooling fan ECU in accordance with the engine coolant temperature, vehicle speed, engine speed, and air conditioning conditions. As a result, good cooling performance has been achieved.
      Starter Control (Cranking Hold Function)* Once the engine switch is pushed, this control continues to operate the starter until the engine has started.
      Air Fuel Ratio Sensor and Heated Oxygen Sensor Heater Control Maintains the temperature of the air fuel ratio sensor and heated oxygen sensor at an appropriate level to increase accuracy of detection of the oxygen concentration in the exhaust gas.
      Engine Immobiliser Prohibits fuel delivery and ignition if an attempt is made to start the engine with an invalid key.
      Air Conditioning Cut-off Control By turning the compressor with pulley assembly on or off in accordance with engine operating conditions, driveability is maintained.
      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)

      *: Models with entry and start system

  3. FAIL-SAFE


    1. When a malfunction of any of the sensors is detected, there is a possibility of an engine or other malfunction occurring if the ECM were to continue normal control. To prevent such a problem, the fail-safe function of the ECM either relies on the data stored in memory to allow the engine control system to continue operating, or stops the engine if a hazard is anticipated. For details, refer to the Repair Manual.

  4. DIAGNOSIS


    1. When the ECM detects a malfunction, the ECM records information related to the fault. Furthermore, the Malfunction Indicator Lamp (MIL) in the combination meter assembly illuminates to inform the driver.

    2. The ECM also stores Diagnostic Trouble Codes (DTCs) for malfunctions it has detected. The DTCs can be accessed by using the Global TechStream (GTS).

    3. For details, refer to the Repair Manual.