GENERAL INFORMATION

The common rail fuel injection system consists of sensors which detect the condition of the diesel engine, an engine electronic control unit (engine-ECU) which controls the system based on signals from these sensors, and actuators which operate according to control commands from the engine-ECU. The engine-ECU carries out activities such as fuel injection control and idle speed control. In addition, the engine-ECU is equipped with several self-diagnosis functions which make troubleshooting easier in the event that a problem develops.

FUEL INJECTION CONTROL

The injector drive time, the injection timing and the fuel pressure are controlled so that the appropriate quantities of fuel are supplied to the engine in response to engine conditions which can change frequently. A single injector is mounted at each cylinder. The supply pump increases the fuel pressure to the pressure which is required for high-pressure injection, and then send the fuel each injector.

IDLE SPEED CONTROL

The idle speed is kept at the optimum speed by controlling the fuel injection quantity in accordance with changes in idling conditions and engine load during idling.
The engine-ECU drives the fuel injector to keep the engine running at the pre-set idle target speed in accordance with the engine coolant temperature and A/C and other electrical load.

SELF-DIAGNOSIS FUNCTION

When an abnormality is detected in any of the sensors or actuators, the engine warning lamp illuminates to warn the driver.
When an abnormality is detected in any of the sensors or actuators, a diagnosis code number corresponding to the problem which occurred is stored.
The RAM data relating to the sensors and actuators which is stored in the engine-ECU can be read using the M.U.T.-III. In addition, the actuator can be force-driven under certain conditions.

OTHER CONTROL FUNCTIONS

9. AS&G system control <Vehicles with AS&G system>
The AS&G-ECU mostly controls the AS&G system [Refer to GROUP 17 - Auto Stop and Go (AS&G) System <M/T> - General Information

]. The engine-ECU makes a judgment about the following and sends a signal to the AS&G-ECU.

Auto Stop Prohibition Control
When one or more of following conditions are satisfied during idling, the engine-ECU should send the auto stop prohibition signal to the AS&G-ECU.

The engine coolant temperature is lower than approximately 50°C or is higher than approximately 90°C.
The intake air temperature is higher than approximately 50°C.
When one or more of the following conditions are satisfied, the vehicle is in "auto stop prohibition status" by electrical load.

The amount of the vehicle current consumption is more than the specified value.
The power generation control is in the forcible full charge mode.

When the battery is determined as being deteriorated.
Diagnosis code No. P0622, diagnosis code No. P1608 or diagnosis code No. U1004 is detected.
The diagnosis code causing the MIL to illuminate is detected.
Approximately 30 seconds have not been taken since the engine started.
When the small injection quantity learning is requested.

Forcible Auto Start Request Control
When one or more of following conditions are satisfied during the auto stop, the engine-ECU should send the engine start request signal to the AS&G-ECU.

The engine coolant temperature is lower than approximately 40 °C.
The amount of the vehicle current consumption is more than the specified value.
Diagnosis code No. P1608 is detected.
When the DPF regeneration is requested.

Items		Specifications
Engine-ECU	Identification No. (Part No.)	1860B814 <M/T - 2WD> 1860C224 <M/T - 4WD> 1860B815 <A/T>
Sensors	Air flow sensor	Heat sensitizing type
	Engine oil pressure switch	Contact switch type
	Barometric pressure sensor	Semiconductor type
	Intake air temperature sensor	Thermistor type
	Engine coolant temperature sensor	Thermistor type
	Accelerator pedal position sensor	Hall element type
	Camshaft position sensor	Magneto resistance element type
	Crank angle sensor	Magneto resistance element type
	Manifold absolute pressure sensor	Piezo resistive semiconductor type
	Throttle position sensor	Hall element type
	Battery temperature sensor	Thermistor type
	Battery current sensor	Hall element type
	Fuel temperature sensor	Thermistor type
	Exhaust differential pressure sensor	Piezo resistive semiconductor type
	EGR gas temperature sensor	Thermistor type
	EGR valve position sensor	Hall element type
	No. 1 exhaust gas temperature sensor	Thermistor type
	No. 2 exhaust gas temperature sensor	Thermistor type
	No. 3 exhaust gas temperature sensor	Thermistor type
	Rail pressure sensor	Piezo resistive semiconductor type
	Water level switch	Contact switch type
Actuators	Engine control relay	Contact switch type
	EGR valve	DC motor type, having brushes
	Suction control valve	Duty cycle type solenoid valve
	Fuel pump relay	Contact switch type
	Injector type and number	Solenoid control type, 4
	Injector identification mark	G3S4
	Throttle valve control servo	DC motor type, having brushes
	Variable geometry control solenoid valve	Linear type solenoid valve
	EGR cooler bypass control solenoid valve	ON/OFF type solenoid valve
	A/C compressor relay	Contact switch type
	Starter relay	Contact switch type

GENERAL INFORMATION

FUEL INJECTION CONTROL

IDLE SPEED CONTROL

SELF-DIAGNOSIS FUNCTION

OTHER CONTROL FUNCTIONS

FUEL INJECTION SYSTEM DIAGRAM