The intake shutter is mounted on the intake manifold. The intake shutter is fully open when the engine is operating. To stop the engine, the VSV operates in accordance with the signals from the ECU, and the actuator closes the intake shutter. As a result, the amount of vibration is reduced when the engine is stopped.

REFERENCE

VSV (Vacuum Switching Valve)

Signals received from the ECU cause the VSV to switch the pressure applied to the actuator between atmospheric and vacuum pressures.

EGR (Exhaust Gas RecirculationSystem)

In the EGR system, the ECU controls the vacuum regulator valve based on the signals that are sent by various sensors, in order to operate (open and close) the EGR valve. This causes a portion of the post-combustion gases to recirculate through the intake manifold to slow down the combustion speed. This lowers the combustion temperature and reduces the generation of nitrogen oxides. Through the adoption of the diesel throttle, it has become possible to increase the intake manifold pressure in order to stabilize the EGR volume.

Vacuum Regulator Valve

The vacuum regulator valve operates in accordance with the signals from the ECU to turn ON/OFF the vacuum (generated by the vacuum pump) that actuates the EGR valve.

EGR Valve

The vacuum that is sent by the vacuum regulator valve operates (opens and closes) the EGR valve to introduce the post-combustion gases into the intake manifold.

Operation of EGR System

The operation of the EGR is stopped under the conditions listed below in order to ensure drivability and reduce black smoke.

When the coolant temperature is low.

When the vehicle is being driven under high-load conditions.

When the engine is decelerating (the EGR operates during idle).

When the vehicle is being driven at high altitudes.

On 15B-FTE and 1HD-FTE engines, the mounting position of the EGR valve has been improved in order to prevent its performance from being affected by the intake air temperature.

On the 15B-FTE engine, a dual construction EGR pipe has been adopted. The coolant water flows along the outside of the pipe to cool the EGR gases. Thus, the intake air is prevented from being warmed by the EGR gases.

Intake Shutter Inspection

To inspect the intake shutter, connect a vacuum gauge to the diaphragm, and verify that the actuator rod moves when the specified amount of vacuum is applied to it. Measure the resistance between the VSV terminals for the intake shutter.

Diesel Throttle Inspection

An inspection of the diesel throttle consists of an inspection of the throttle motor. Remove the throttle motor connector and measure the resistance between the specified terminals.

The diesel throttle is mounted on the intake manifold. The throttle valve, which operates independently from the accelerator pedal, uses the diesel throttle control motor (step motor) to regulate the throttle opening accordance with the signals received from the ECU.

Purpose :

1. Ensures an optimal amount of EGR volume throughout the operating range by increasing the intake manifold vacuum.

2. Reduces the intake noise and vibration by closing the throttle valve at idle.

3. Reduces vibrations by fully closing the throttle when stopping the engine in order to reduce the amount of air intake volume.

Diesel Throttle Operation

1. When the engine is running, the opening of the throttle is optimally adjusted according to the engine speed, engine load conditions, and the EGR volume.

2. When the engine is stopped, the throttle closes fully to shut off the intake of air. By minimizing the compression in the cylinder, vibrations that occur when stopping the engine are reduced.

REFERENCE

Intake Constrictor Control (1KZ-TE)

The intake constrictor control contains a main valve and a sub valve. The main valve operates with the accelerator pedal and the sub valve operates with the actuators that function with two VSVs (VSV1 and VSV2), which operate in accordance with the signals received from the ECU.

Determining Common-rail Fuel Pressure

A fuel pressure that matches the operating conditions of the engine is calculated according to the actual injection volume that has been determined based on the signals from the sensors, and the engine speed. The ECU sends signals to the SCV to adjust the fuel pressure that is generated by the supply pump.

REFERENCE

Determining Common-rail Fuel Pressure

Diagnostic Functions

As with the EFI system of the gasoline engine, the EFIdiesel also features a diagnostic MOBD (OBD) function. The MIL (Malfunction Indicator Lamp) illuminates if a malfunction is detected in the ECU itself or in the electrical system. The area of the malfunction will be indicated by a DTC(Diagnostic Trouble Code) number. After the malfunction has been resolved, the MIL will disappear. However, the DTC will remain stored in the ECU memory.

Check (Test) mode

The diagnosis function consisted of a normal mode and a check (or test) mode. While the normal mode performs normal diagnosis, the check (or test) mode features an increased level of sensitivity to detect even more detailed malfunction conditions.

Freeze frame data

The ECU stores in its memory the conditions of the engine at the time the malfunction occurred. The conditions that existed at that time can be later retrieved and reviewed through the use of a hand-held tester.

Fail-safe

The ECU assumes the fail-safe mode if a malfunction occurs in some of the diagnostic items. This mode initializes the signals to their prescribed values in order to enable the vehicle to be driven.

DTC (Diagnostic Trouble Code) Display

Depending on the model, the check connector might come as a DLC or DLC3. The DTC (Diagnostic Trouble Code) can be monitored by shorting the terminals of the connector and counting the number of blinks. If no malfunctions have occurred, the number of blinks will correspond to normal conditions. One of the methods for accessing the DTCs (Diagnostic Trouble Codes) is to use a hand-held tester. The DTC numbers can be displayed on the hand-held tester screen. A hand-held tester can be used also for displaying the conditions of the engine or of the sensor signals (reference values) in addition to displaying the DTC numbers.

Active Test

During an active test, a diagnostic tester is used for outputting commands to the ECU in order to drive the actuators. This test determines the integrity of the system or parts by monitoring the operation of the actuators or by reading the engine ECU data.

Service Hint

Reading the DTC (Diagnostic Trouble Codes)

In the Repair Manual, the detection item, detecting condition and trouble area are included for each DTC, so refer to the Repair Manual when troubleshooting.

Inspection Using a Circuit Tester

Perform an inspection in accordance with the Inspection Chart for each diagnostic trouble code. The inspection method is identical to the electronic fuel injection (EFI) system of a gasoline engine.

ECU inspection

Measuring the voltage and resistance at the ECU/EDU terminals.

Relay inspection

Measuring the voltage and resistance of the relay terminals.

Sensor inspection

Measuring the voltage and resistance between the sensor terminals.

Inspection Using a Hand-held Tester

Through the use of a hand-held tester, the conditions of the ECU, EDU and sensor can be monitored on the tester. In the negative test mode, the hand-held tester can activate the actuators in order to simulate the vehicle’s operating conditions. Follow the instructions given bellow to clear the DTCs(Diagnostic Trouble Codes) that are stored in ECU memory. Execute “Clear” on the hand-held tester. Disconnect the specified fuse and the positive terminal for the battery (this procedure differs from model to model).

Conventional EFI-diesel

Common-rail EFI-diesel

4. Comparison of the target injection timing and the actual injection timing

As with the convention EFI-diesel, the basic injection timing of the common- rail EFI-diesel is determined through the engine speed and the accelerator pedal opening angle, and by adding a correction value based on the water temperature and the intake air pressure (volume). The ECU sends injection signals to the EDU and advances or retards the timing to adjust the injection starting timing.

Starting Control

Injection Volume Control During Starting

The starting injection volume is determined by adjusting the basic injection volume in accordance with the starter ON signals (ON time) and coolant temperature sensor signals. When the engine is cold, the coolant temperature will be lower and the injection volume will be greater. To determine the starting injection timing is corrected in accordance with the starter signals, water temperature and engine speed. When the water temperature is low, if the engine speed is high, the injection timing is advanced.

Injection Rate Control

Split Injection

A radial plunger type pump performs split injection (two-time injection) when starting the engine at an extremely low temperature (or under -10 degrees) to improve startability and reduce the generation to white and black smoke.

Pilot Injection

The common-rail EFI-diesel uses pilot injection. In the pilot injection system, a small amount of fuel is initially injected before the main injection. When the main injection starts, the fuel that has been injected in advance is already ignited, enabling the fuel of the main injection to ignite smoothly.

Idle Speed Control

Based on the signals from the sensors, the ECU calculates the target speed in accordance with the driving conditions. The ECU then compares the target value with the (engine speed) signal from the engine speed sensor and controls the actuators(SPV/injector) to regulate the injection volume in order to correct the idle speed. The ECU effects idle-up control (in order to improve the engine’s warm-up performance) during fast idle when the engine is cold, or during air conditioner/power heater operations. Also, in order to prevent fluctuations in idle speed caused by a reduction in engine load that occurs when the A/C switch is turned off, the volume is automatically corrected before the engine speed fluctuates.

Idle Vibration Reduction Control

This control detects the fluctuations in the engine speed during idle caused by the variances in the injection pump or nozzles, and corrects the injection volume for each cylinder. Consequently, idle vibration and noise are reduced.

1. Engine speed correction control

Symptom:

Increased injection volume due to a rise in the pressure in the pump.

Description of control:

Injection volume reduced according to the engine speed.

2. ECT control

Symptom:

Shocks occurs during shifting.

Description of control:

Injection volume is reduced during shifting.

3. Glow plug control (Axial plunger type pump)

Symptom:

Glow plugs turn ON when starting a cold engine.

Description of control:

Controls glow plug conditions according to the coolant temperature.

4. Intake heater control (Radial plunger type pump)

Symptom:

Intake heater turns ON to warm up the intake air when starting a cold engine.

Description of control:

Controls intake heater conditions according to the coolant temperature.

5. Air condition cut control

Symptom:

Intake heater turns ON to warm up the intake air when starting a cold engine.

Description of control:

Controls glow plug conditions according to the coolant temperature.

6. Dulling control

Symptom:

Torque fluctuation due to change in the injection volume during acceleration.

Description of control:

The injection volume is changed gradually immediately after the accelerator is opened or closed.

The ECU performs the following functions to determine the injection timing:

Conventional EFI-diesel

1. Determination of the target injection timing

2. Detection of the actual injection timing

3. Comparison of the target injection timing and the

actual injection timing

Common-rail EFI-diesel

4. Comparison of the target injection timing and the actual injection timing

Conventional EFI-diesel

1. Determination of the target injection timing

The target injection timing is determined by calculating the basic injection timing through the engine speed and the accelerator pedal opening angle, and by adding a correction value based on the water temperature, intake air pressure, and the intake air temperature.

Conventional EFI-diesel

1. Determination of the target injection timing

Conventional EFI-diesel

2. Detection of the actual injection timing

The detection of the actual injection timing is performed through a calculation based on the engine speed and crankshaft position signals. As with injection volume control, the variances that occur in injection timing control between pumps are corrected through the use of a correction resistor or a correction ROM.

REFERENCE

Injection Timing Detection

Conventional EFI-diesel

The cam plate and the rotor (which generates the NE signal of the engine speed sensor) rotate in unison. Therefore, the ECU is able to detect the timing when the plunger moves and an actual injection takes place by way of the position of the NE signal.

To address the phase discrepancy that occurs between the actual injection timing and the NE signal due to the individual variances of the pumps, a correction resister is used to correct and recognize it as the standard position. Compare the NE signal and the TDC signal of the crankshaft angle sensor and calculates the injection timinng in relation to the engine crankshaft angle as being the actual injection timing.

Conventional EFI-diesel

3. Comparison of the target injection timing and the actual injection timing

The ECU compares the target injection

timing and the actual injection

timing and sends timing advance and

timing retard signals to the timing

control valve so that the actual injection

timing and the target injection

timing match.

The ECU performs the following three functions to determine the injection volume:

1. Calculation of basic injection volume

2. Calculation of maximum injection volume

3. Comparison of basic injection volume and maximum injection volume

1. Calculation of basic injection volume

The calculation of the basic injection volume is made based on the signals of the engine speed and the amount of pedal effort applied to the accelerator pedal.

2. Calculation of maximum injection

volume

The calculation of the maximum injection volume is made based on the signals from the engine speed sensor (NE sensor), water temperature sensor, intake air temperature sensor, fuel temperature sensor, and turbo pressure. In the common-rail type, the signals from the fuel pressure sensor are also used.

Injection Volume Correction

Intake air pressure correction

The injection volume is corrected in accordance with the intake air pressure (volume).

Intake air temperature correction

The density of the intake air (air volume) varies in accordande with the temperature of the intake air. (Low intake air temperature →Injection volume increase correction)

Fuel temperature correction

High fuel temperature →Injection volume increase correction

Cold engine correction

Low water temperature →Injection volume increase correction

Fuel pressure correction

In a common-rail type diesel, the changes in the fuel pressure in the common- rail are detected based on the signals from the fuel pressure sensor. If the fuel pressure is lower than the target pressure, the length of time the injector nozzles remain open is extended.

Calculation of maximum injection volume

The ECU compares the calculated basic injection volume and the maximum injection volume and determines the smaller one to be the injection volume. Accelerator 60 % constant speed driving Accelerator 100 % sudden acceleration

3. Comparison of basic injection volume and maximum injection volume

The difference in the actual injection volume in the conventional EFI-diesel created by the mechanical variances that occur from pump to pump are corrected.

REFERENCE

About the correction ROM :

Authorized workshops such as pump service shops use special tools to measure the pumps to replace the correction ROMs or to make corrective adjustments.

Other types of corrections:

In addition to the injection volume that has been determined here, fuel temperature correction is also made on some vehicle models. If the fuel temperature is high, the actual injection volume is lower (due to the low density) than the instructed value. Therefore, the instructed value must be increased.

Engine Speed Sensor
The engine speed sensor is fitted in the injection pump. It consist of a rotor that is pressed over a drive shaft, and a sensor. Electric signals are generated in the sensor (coil) in accordance with the rotation of the rotor.
Engine Speed Sensor
Here is the relationship between the rotation of the rotor and the generated waveform. The ECU counts the number of pulses to detect theengine speed. The rotor makes half a revolution for each revolution of the engine. The ECU detects the reference angle from the missing tooth portion, which is located along the cicumference of the rotor.
Engine Speed Sensor
The 1CD-FTV common-rail EFI-diesel engine uses the crankshaft position sensor to detect the engine speed just as in the EFI system of a gasoline engine, in place of the engine speed sensor used in a conventional EFI-diesel engine. The crankshaft position sensor of the common-rail EFIdiesel engine outputs the same NE signal that is output by the engine speed sensor of the conventional EFI-diesel engine.
Crankshaft Position Sensor
The crankshaft position sensor is mounted on the engine block. It detects the crankshaft angle reference position in the form of a TDC signal. HINT: The crankshaft position sensor of common-rail type output the engine speed (NE) signals. It detects the crank angle based on these NE signals. A pulse is generated when the protrusion provided on the crankshaft padded near the sensor due to the revolution of the crankshaft. A pulse is generated once for every revolution of the crankshaft, and this is detected in the form of a crankshaft angle reference position signal.
Camshaft Position Sensor
A camshaft position sensor is used on some engines (1CD-FTV) in place of a crankshaft angle reference position is detected in the form of a G signal.
1ND-TV Engine
For the 1ND-TV engine a hall element type camshaft position sensor is used. The timing trigger on the timing sprocket detects the position of the camshaft by sending one signal for every two revolutions of the crankshaft.
Turbo Pressure Sensor
The turbo pressure sensor is connected to the intake manifold via an air hose and a VSV, and detects the intake manifold pressure (intake air volume).

REFERENCE
Turbo Pressure Sensor
The VSV operates in accordance with the signals form the ECU and switched the pressure that is applied to the actuator between atmosphere and vacuum. Vacuum Atmosphere
Water Temperature/Intake Air Temperature/ Fuel Temperature Sensor
There are three types of temperature sensors that are used for controlling the EFI-diesel:
The water temperature sensor is mounted on the engine block to detect the temperature of the engine coolant. The intake air temperature sensor is mounted on the intake pipe of the engine and detects the temperature of the intake air. The fuel temperature sensor is mounted on the pump and detects the temperature of the fuel. Each type of temperature sensor has a built-in thermistor whose resistance varies in accordance with the temperature and its characteristics are as indicated in the diagram.
Fuel Pressure Sensor
The fuel pressure sensor that is used in the common-rail type diesel detects the fuel pressure in the common-rail. Based on the signals from the fuel pressure sensor, the ECU controls the SCV (Suction Control Valve) to generate a prescribed fuel pressure in accordance with the driving conditions.
Air Flow Meter
A hot-wire type air flow meter has been adopted in the common-rail EFI-diesel to detect the intake air volume.

The common-rail system consists of precision parts and uses highly pressurized fuel. Therefore, extreme care must be taken to ensure that foreign matter does not enter the system.

1. Thoroughly clean and wash the work area to remove any dirt or rust before disassembling any parts in order to prevent the interior of the fuel system from becoming contaminated during disassembly.

2. Place the parts in plastic bags to prevent the entry of foreign matter and to protect the sealing surfaces from damage during storage.

3. Thoroughly clean the parts before assembly, making sure that their sealing surfaces are free of foreign matter such as dust or cutting chips.

Injection Pipe Installation

Observe the precautions given below in order to install the injection pipes.

1. To reinstall a removed part to its original position, wash the injection pipes and make sure that their sealing surfaces are free of foreign matter or cuts before installing the pipes.

2. Because the injection pipes cannot accommodate excessive alignment changes, changes in the combination of the installed parts must be avoided. (The pipes should not be reused on a different engine, and the cylinder order of the injectors should not be altered.)

3. For the same reason, also replace the pipes with new parts if a part that affects the alignment must be replaced. Instances in which the injection pipes must be

replaced :

When injectors or the common-rail is replaced.

Instance in which the fuel inlet pipe must be replaced :

When the supply pump or the common-rail is replaced.

REFERENCE

Pipe Fitting Conditions

The common-rail EFI-diesel system maintains fuel at an extremely high pressure. The areas in which the pipes and parts are joined use a type of pipe union that is sealed by deforming its sealing surface. For this reason, if either the injector, common-rail, or the supply pump is replaced, the pipes must also be replaced because their matching surfaces have been changed. Failure to replace the pipe will cause a fuel leak. Fuel Leak Inspection

Check for fuel leaks after tightening the union. Use the active mode of a hand-held tester to increase the fuel pressure in order to check for fuel leaks. Before starting the engine, first inspect the assembly conditions. Then, operate the engine at idle to check for fuel leaks. Finally, perform an active test. To perform an active test, select the Fuel Leak Test in the active test mode of a hand-held tester. If a hand-held tester is unavailable, quickly depress the accelerator pedal entirely to accelerate to the maximum engine speed, and maintain that speed for 2 seconds. Repeat this operation several times.

SCV Inspection

Inspect the SCV as Follows:

Disconnect the SCV1and SCV2 connectors. Using an ohmmeter, measure the resistance between terminals as shown. Specified Resistance:1.5-1.7 at 20 °C (degrees Celsius), 68 °F (degrees Fahrenheit) If the resistance does not equal the specified resistance above, replace the pump.

Common-rail

The common-rail, pressure limiter, and the fuel pressure sensor may not be reused. Both the pressure limiter and the fuel pressure sensor are fitted through plasticity deformation. Therefore, once they are removed, they must be replaced together with the common-rail.

HINT:

These components are available as a single integrated service part.

Injector Installation

The installation of the injectors must be performed carefully. Using clean diesel fuel, wash the sealing surfaces of the injectors and injection pipes just before their installation. Make sure to follow the installation instructions given in the Repair Manual of the respective model. Pay particular attention to the installation direction of the injectors and their alignment with the cylinder head.

Power Balance Test Procedure

Through the use of the active test mode of the hand-held tester, a power balance test can be performed by disabling the injector, one cylinder at a time. Because the fuel in the pipe is highly pressurized, never start the engine with the unions of the pipes loosened. Fuel is injected at a high pressure via electronically controlled injectors. Therefore, the opening pressure tests or spray pattern tests for the injection nozzles of the conventional diesel engine are not applicable to these injectors.

The signals from the ECU are amplified by the EDU to operate the injector. High voltage is used particularly when the valve is open in order to open the nozzles. The injection volume and timing are controlled by adjusting the opening and closing timing of the injectors, just as in the EFI system of a gasoline engine.

Injection volume control

Injection timing control

Construction of Injector

Correction Resistor of Injector

Given the same injection interval, mechanical variances will still cause the injection volume from injector to injector to vary. To enable the ECU to correct these variances, the injectors are provided with a correction resistor for each injector. Based on information received from each correction resister, the ECU corrects the variances in injection volume between the injectors. These correction resistors are provided to enable the ECU to identify the injectors, and are not connected to the injector circuit.

HINT:

The correction resistor,which is listed above, is not attached to the injector of 1ND-TV E/G. 3 types of injectors are adopted based on the difference of the injection volume, and the indentification numbers (A, B, C) are attached on the top of each injector.

Types of Injector Correction Resistor for 1CD-FTV E/G

There are 25 types of injectors as indicated below, each provided with a different correction resistor. When replacing an injector, the ECU automatically makes the proper fuel correction, so it is not necessary to replace it with one with the same correction resistance.

Injector Operations

1. Before the injector operation

The fuel that has been fed from the common-rail separates into the control chamber and the bottom of the needle. In this state, the needle is pushed down by the pressure in the control chamber and by the spring, and the nozzle remains closed.

2. When the solenoid valve opens

When the actuating voltage is applied by the ECUEDU, the solenoid valve opens and the pressure in the control chamber decreases.

3. When the needle opens

Due to the operation of the orifice, the pressure at the bottom of the needle remains high, and the nozzle opens to inject fuel.

4. When the solenoid valve closes

When the voltage applied by the ECU-EDU ends, the spring force causes the solenoid valve to close and the pressure in the control chamber increases again.

5. When the needle closes

Due to the pressure in the control chamber and the force of the spring, the needle descends and closes the nozzle to end the injection.