ECD SYSTEM

FUNCTION OF MAIN COMPONENTS

The main components of the 2WW engine control system are as follows:

Component		Quantity	Function
ECM		1	The ECM performs overall control of the engine control system to suit the operating conditions of the engine in accordance with the signals from the sensors.
Atmospheric Pressure Sensor (Built into ECM)		1	This sensor, which is built into the ECM, uses semiconductors to detect the atmospheric pressure.
Atmospheric Temperature Sensor (Built into ECM)		1	This sensor, which is built into the ECM, uses a thermistor to detect the atmospheric temperature.
Intake Mass Air Flow Meter Sub-assembly	Mass Air Flow Meter	1	This sensor uses a built-in hot-wire to directly detect the intake air mass.
Intake Mass Air Flow Meter Sub-assembly	Intake Air Temperature Sensor (Built into Intake Mass Air Flow Meter Sub-assembly)	1	This sensor detects the intake air temperature by means of an internal thermistor.
Intake Air Temperature Sensor (for Compressed Intake Air)		1	This sensor detects the intake air temperature past the turbocharger and intercooler.
Diesel Throttle Body Assembly	Throttle Control Motor	1	This motor regulates the opening of the diesel throttle valve in accordance with the signals from the ECM.
Diesel Throttle Body Assembly	Throttle Position Sensor	1	This sensor detects the diesel throttle valve opening angle.
Accelerator Pedal Position Sensor		1	This sensor detects the amount of pedal effort applied to the accelerator pedal.
Fuel Temperature Sensor		1	This sensor detects the fuel temperature in the fuel line before the supply pump assembly by means of an internal thermistor.
Fuel Pressure Sensor		1	This sensor uses built-in semiconductors to detect the internal pressure of the common-rail assembly
Crankshaft Position Sensor		1	This sensor detects the engine speed and performs the cylinder identification.
Camshaft Position Sensor		1	This sensor performs the cylinder identification.
Turbo Pressure Sensor Assembly		1	This sensor detects the intake manifold pressure.
Engine Coolant Temperature Sensor		1	This sensor detects the engine coolant temperature by means of an internal thermistor.
Air Fuel Ratio Sensor		2	This sensor detects the oxygen concentration in the exhaust gas.
Nozzle Vane Position Sensor		1	This sensor detects the nozzle vane position.
Swirl Control Valve Position Sensor		1	This sensor detects the diesel swirl control valve opening angle.
Actuator (for Turbocharger)		1	This actuator regulates the opening of the nozzle vane in accordance with the signals from the ECM.
Actuator (for Swirl Control)		1	This actuator regulates the opening of the swirl control valve in accordance with the signals from the ECM.
Glow Plug Controller		1	The glow plug controller controls the length of time for which the current is applied to the glow plug assemblies in accordance with the signals from the ECM.
Fuel Quantity Control Valve		1	The valve position is controlled by the signals from the ECM, and a fuel volume that suits the valve position is drawn into the pumping portion (plunger portion).
Pressure Discharge Valve		1	The pressure discharge valve regulates the fuel pressure.
Injector Assembly		4	The injector injects the fuel to the combustion chamber in accordance with the signals from the ECM.
Fuel Pump Assembly		1	The fuel pump assembly feeds fuel to the supply pump assembly.
Glow Plug Assembly		4	The glow plug assembly heats the combustion chamber.

SYSTEM CONTROL

The engine control system of the 2WW engine has the following systems:

System	Outline
Fuel Injection Control	Based on the signals received from the sensors, the ECM determines the fuel injection volume and fuel injection timing in accordance with the engine condition.
Fuel Pressure Control	Based on the signals received from the fuel pressure sensor, the ECM controls fuel pressure using the fuel quantity control valve and pressure discharge valve in accordance with engine operating conditions. For details of the fuel quantity control valve operation, see the 2WW Fuel section.
Fuel Pump Control	Fuel pump operation is controlled by signals from the ECM in order to feed fuel to the supply pump.
Glow Plug Control	The ECM sends signals to the glow plug controller in accordance with engine conditions. Based on the signals, the glow plug controller controls the length of time for which the current is applied to the glow plug assemblies in each cylinder. Detects individual disconnections of circuit wires and short circuits by the use of the glow plug controller.
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 vibration when the engine is stopped.
Fuel Heater Control	Based on the signals received from the pre-fuel pressure and pre-fuel temperature sensors in the fuel filter, the ECM controls the fuel heater.
Swirl Control	Based on the signals received from the sensors, the ECM controls the actuator (for swirl control), in order to open and close the valve.
Air Fuel Ratio Sensor Heater Control	The ECM controls the air fuel ratio sensor heater according to the engine condition in order to promote the warm-up of the air fuel ratio sensor.
Turbocharger Control	Based on the signals received from the sensors, the ECM controls the actuator in accordance with the engine condition.
Cooling Fan Control	Cooling fan operation is controlled by signals from the ECM based on the engine coolant temperature, air conditioning condition, engine speed and vehicle speed. After the engine is stopped (the ignition switch is off1 or the engine switch is off2), the ECM operates the cooling fan according to the driving conditions and engine condition.
Exhaust Gas Recirculation (EGR) Control	Based on the signals received from the sensors, the ECM determines the EGR volume via the EGR valve and EGR cooler bypass switching valve in accordance with the engine condition. For details, see the 2WW Emission Control section.
Catalyst Regeneration Control	The ECM judges the NSR catalyst condition based on the fuel injection volume, intake air mass, and exhaust gas temperature to control the injector assemblies for NSR catalyst regeneration control. For details, see the 2WW Emission Control section.
Catalyst Regeneration Control	The ECM judges the DPF catalyst condition based on signals from the exhaust gas temperature sensor, differential pressure sensor assembly and air fuel ratio sensor to control the throttle control motor and injector assemblies for DPF catalyst regeneration control. For details, see the 2WW Emission Control section.
Starter Control*2	Once the engine switch is pushed, this control continues to operate the starter until the engine is started. For details, see the 2WW Starting section. For details, see the 2WW Starting section.
Air Conditioning Cut-off Control	This control turns the air conditioning compressor on or off in accordance with the engine condition to maintain driveability.
Engine Immobiliser	Prohibits fuel injection if an attempt is made to start the engine with an invalid key.
Oil Maintenance Management System	The oil maintenance information message is shown on the multi-information display according to the vehicle condition to inform the driver. Remaining oil maintenance mileage is shown on the multi-information display to inform the driver. For details, see the Meter / Gauge / Display section.
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, the ECM diagnoses and memorizes the failed section.
Fail-safe	When the ECM detects a malfunction, the ECM stops or controls the engine in accordance with the data already stored in the memory.

*1: Models without entry and start system

*2: Models with entry and start system