DENSO COMMON RAIL SYSTEM (CRS). SERVICE MANUAL (2007)

Operation Section

1-76

7.2 E-EGR System (Electric-Exhaust Gas Recirculation)

(1) General Description

• The E-EGR system is an electronically controlled EGR system. The EGR system recirculates a portion of the exhaust

gases into the intake manifold in order to lower the combustion chamber temperature and reduce NOx emissions.

However, operation of the EGR system may reduce engine power output and affect drivability. For this reason, in the

E-EGR system, the engine ECU controls the EGR to achieve an optimal EGR amount.

Operation Conditions Example

- This operates in the operation region fulfilling the starting conditions below (one example).

· Engine Operating Conditions

· · · · · Except during engine warm-up and startup,

does not overheat, etc.

· EGR Operating Range

· · · · · · · · For Engine Medium Load

Engine Speed

Q000501E

(2)

Operation

•

After the vacuum pump generates a vacuum, the E-VRV (electric-vacuum regulation valve) regulates the vacuum and

directs it to the diaphragm chamber of the EGR valve. In response to this vacuum, the diaphragm pushes the spring

downward, which determines the opening of the EGR valve and controls the EGR volume.

•

The EGR cooler, which is provided in the EGR passage between the cylinder head and the intake passage, cools the

EGR in order to increase the EGR volume.

•

The EGR cutoff VSV, which opens the diaphragm chamber to the atmosphere when the EGR valve is closed, helps

to improve response.

Diaphragm

Vacuum Pump

Vacuum Damper

EGR Valve

E-VRV

Spring

EGR Shut-Off VSV

Coolant

EGR Cooler

Engine Speed

Engine

Accelerator Opening

Control Unit

Intake Air Pressure And

Atmospheric Pressure

Coolant Temperature

Exhaust

Manifold

Intake Air

Relationship Between Vacuum and EGR Valve Opening

Low

Vacuum

High

Small

EGR Valve Opening

Large

Q000903E

Operation Section

1-77

To Increase the EGR Quantity

- The E-VRV duty ratio is controlled^*1. In the stable condition shown in the bottom center diagram, an increase in the

current that is applied to the coil causes the attraction force FM in the coil to increase. When this force becomes

greater than the vacuum force FV that acts on the diaphragm, the moving core moves downward. Along with this

movement, the port from the vacuum pump to the upper chamber of the diaphragm opens. Consequently, the out-

put vacuum increases, which causes the EGR valve to open and the EGR volume to increase. Meanwhile, because

"increased output vacuum equals increased FV", the moving core moves upward with the increase in FV. When

FM and FV are equal, the port closes and the forces stabilize. Because the vacuum circuit of the EGR is a closed

loop, it maintains the vacuum in a stabilized state, provided there are no changes in the amperage.

< NOTE >

: The engine ECU outputs sawtooth wave signals with a constant frequency. The value of the current is the effective (average) value of these

signals. For details, see the explanation of the HP3 supply pump and SCV.

To Decrease the EGR Volume

- A decrease in the current that is applied to the coil causes FV to become greater than FM. As a result, the dia-

phragm moves upward. The moving core also moves upward in conjunction with the movement of the diaphragm,

causing the valve that seals the upper and lower diaphragm chambers to open. Consequently, the atmospheric

pressure in the lower chamber enters the upper chamber, thus reducing the output vacuum. This causes the EGR

valve to close and the EGR volume to decrease. Because "decreased output vacuum equals decreased FV", the

moving core moves downward with the decrease in FV. When FM and FV are equal, the port closes and the forces

stabilize.

From Vacuum Pump

To EGR Valve

Moving Core

Valve

Spring

Diaphragm

Coil

Stator Core

Atmosphere

FM > FV

FM < FV

EGR Quantity Increased

EGR Quantity Decreased

Q000904E

Operation Section

1-78

7.3 Electronically Controlled Throttle (Not Made By DENSO)

(1) General Description

• The electronically controlled throttle is located upstream of the EGR valve in the intake manifold. It controls the throttle

valve at an optimal angle to regulate the EGR gas and reduce noise and harmful exhaust gases.

(2) Operation

• Signals from the engine ECU actuate the stepping motor, which regulates the throttle valve opening.

EGR Control

• To further increase the EGR volume when the EGR valve is fully open, the vacuum in the intake manifold can be in-

creased by reducing the throttle valve opening, which restricts the flow of the intake air.

Noise and Exhaust Gas Reduction

• When the engine is being started, the throttle valve opens fully to reduce the emissions of white and black smoke.

• When the engine is being stopped, the throttle valve closes fully to reduce vibration and noise.

• During normal driving, the throttle valve opening is controlled in accordance with the engine conditions, coolant tem-

perature, and atmospheric pressure.

Stepping Motor

Throttle Valve

Q000905E

Operation Section

1-79

7.4 Exhaust Gas Control System

(1) General Description

• The exhaust gas control system is provided to improve warm-up and heater performance. This system actuates the

exhaust gas control valve VSV, which is attached to the exhaust manifold. It increases the exhaust pressure to in-

crease the exhaust temperature and engine load, in order to improve warm-up and heater performance.

Vacuum Pump

Exhaust Gas

Control Valve

Air Cleaner

VSV

Turbo Pressure

Mass Airflow Meter

Sensor

Cylinder

Coolant Temperature

Recognition Sensor

Sensor

ECU

(TDC (G) Sensor)

Exhaust Gas

EGR Valve Position

Accelerator

Control Valve

Sensor

Position Sensor

Warm-Up Switch

Atmospheric

Pressure Sensor

Q000906E

(2) Operation

• The exhaust gas control system operates when the warm-up switch is ON, and all the conditions listed below have

been met.

Operation Conditions

- The EGR is operating.

- The coolant temperature is below 70°C.

- The ambient temperature is below 5°C.

- A minimum of 10 seconds have elapsed after starting the engine.

- The engine speed and fuel injection quantity are in the state shown in the graph below.

[Exhaust Gas Control System Operating Range]

WARM UP

Operating Range

Extremely Low Torque

or Engine Speed Range

Engine Speed

Q000907E

Operation Section

1-80

7.5 DPF System (Diesel Particulate Filter)

(1) General Description

• This system reduces emissions of PM (particulate matter). In order to collect PM, a DPF cleaner with built-in catalytic

filter is mounted on the center pipe. The collected PM is handled with combustion processing during operation.

(2) System Configuration

Rail

Intake Air

G2 Injector

Intercooler

Pressure Sensor

EGR Cooler

VNT Actuator

EGR Valve

Equilibrium

Actuator

Supply Pump

Exhaust Gas

DPF (with

Temperature Sensor

Oxidation Catalyst)

ECU & EDU

Differential Pressure Sensor

Exhaust Gas Temperature Sensor

Q000908E

(3) Various Sensors

Exhaust Gas Temperature Sensor

• The exhaust gas temperature sensor is installed to the front and rear of the DPF to detect the temperature in these

positions. The engine ECU controls the exhaust temperature for PM combustion based on the signals from this sen-

sor. The sensor element is a thermistor.

Thermistor Element

Cover

Exhaust Gas Temperature (

)

Q000909E

Operation Section

1-81

Differential Pressure Sensor

• The differential pressure sensor detects the difference in pressure at the front and rear of the DPF, and outputs a sig-

nal to the engine ECU. The sensor portion is a semiconductor type pressure sensor that utilizes the piezoelectric ef-

fect through a silicon element, and amplifies and outputs the voltage with its IC circuit. When PM is collected and

accumulated in the DPF, the filter clogs and the difference in pressure at the front and rear of the DPF increases.

Therefore, based on the signals from this sensor, the engine ECU judges whether or not to subject PM to combustion

processing.

GND

Pressure (kPa)

Q000910E

(4) Operation

• By optimizing the injection pattern and controlling the exhaust gas temperature based on the exhaust gas temperature

and the difference in pressure at the front and rear of the DPF, PM is collected, oxidized, and self-combusted. When

the exhaust temperature is low, adding after-injection after the main injection raises the exhaust gas temperature to

approximately 250?C and promotes oxidation of the PM. When the PM is collected and accumulated, the post-injec-

tion is added and HC is added to the catalyst to raise the catalyst temperature to 600?C, which is the self-combustion

temperature for PM. This combusts the accumulated PM in a short time. The engine ECU controls the A, B, and C

times and the injection times.

TDC

After-Injection

Post-Injection

Q000506E

Operation Section

1-82

7.6 DPNR SYSTEM (DIESEL PARTICULATE NOx REDUCTION)

(1) General Description

• This system reduces the emissions of PM (particulate matter) and NOx. The DPNR catalyst mounted in the center

pipe collects and regenerates PM and reduces NOx all at the same time. The collected PM is handled with combus-

tion processing during operation.

(2) System Configuration

Exhaust Gas Cleaning

Supply Pump

Device Switch

Device Display Lamp

Intake Restriction Valve

Injector

Engine ECU

Exhaust

Retarder VSV

DPNR Catalyst

Oxidation Catalyst

A/F Sensor

Oxidation Catalyst

Before EGR Cooler

Fuel Addition Valve

A/F Sensor

Exhaust Retarder

NSR Differential Pressure Sensor

Exhaust Gas Temperature Sensor

Q000911E

Operation Section

1-83

8. DIAGNOSIS

8.1 Outline Of The Diagnostic Function

z The diagnostic function enables a system to self-diagnose its own malfunctions. If abnormal conditions occur in the sen-

sors or actuators used in the control systems, the respective systems convert the malfunction signals into codes and

transmit them to the engine ECU. The engine ECU records the transmitted malfunction code into memory. Recorded

codes are output at the diagnostics connector on the vehicle. To inform the driver of the malfunction, the engine ECU

causes the MIL (Malfunction Indicator Light) in the meter to illuminate. Accurate troubleshooting can be performed by

way of the DTCs (Diagnostic Trouble Codes) that are output at the diagnostic connector. For details on actual diagnosis

codes, see the vehicle manual. It is necessary to put the vehicle into the state below before starting inspection.

(1) Pre-Inspection Preparation

• Position the shift lever in "N" or "P".

• Turn OFF the air conditioner.

• Verify that the throttle valve is fully closed.

8.2 Diagnosis Inspection Using DST-1

z The DST-1 can be used in both normal and check modes. Compared to the normal mode, the check mode has a higher

sensitivity to detect malfunctions.

z The check mode inspection is performed when normal codes are output in the normal mode, despite the fact that there

may be malfunctions in the sensor signal systems.

(1) Reading DTCs

1) DST-1 Connection: Connect the DST-1 to the DLC3 termi-

nal.

DLC3

Q000914

2) Reading DTCs: Operate in accordance with the instructions

shown on the screen to display the "DTC check" screen. Se-

Diagnostic Trouble Codes (DTC)

lect either the normal or check mode and read the DTC.

· · ·

< NOTE >

If no DTC appears on the screen, there may be a failure

in the engine ECU.

Execute: Execute

Q000915E

Operation Section

1-84

3) Checking the Freeze Frame Data: If the symptom that out-

puts a DTC cannot be duplicated, check the freeze frame

data.

4) Erasing DTCs from memory: Operate in accordance with

the instructions shown on the screen to display the "DTC

DTC (ECD Erasure)

check" screen. Select "Erase DTCs" to erase the DTCs.

This will erase the DTC and freeze frame data.

< NOTE >

Do you wish to proceed?

If it is not possible to erase the DTC, turn the ignition

switch OFF, and repeat the process.

NG : - OK : +

5) Wiring Harness and Connector Open Circuit Check

Q000916E

< NOTE >

If the DTC output during a diagnostic inspection (in the

check mode) has identified the system with a malfunction,

use the method indicated below to narrow down the area

of the malfunction.

• Erasing DTCs from memory: After reading the DTCs in check mode, erase the DTCs from memory.

• Starting the Engine: Select the check mode and start the engine.

• Malfunctioning system check 1: While the engine is running at idle, shake the wiring harness and connectors of the

system that output the malfunction during the diagnosis (check mode) inspection.

• Malfunctioning system check 2: If the MIL (Malfunction Indicator Light) illuminates when the wiring harness and con-

nectors are shaken, there is a poor contact in the wiring harness or connectors in that area.

8.3 Diagnosis Inspection Using The MIL (Malfunction Indicator Light)

z Before reading a DTC, turn the ignition switch ON to make sure the MIL (Malfunction Indicator Light) illuminates.

z Inspections in the check mode cannot be performed.

(1) Reading DTCs

Short circuiting the connector

• Using the STT, short circuit between DLC1 terminals 8 (TE1) and 3 (E1) or between DLC3 terminals 13 (TC) and 4

(CG).

DLC1

DLC3

15 14 13 12

TE1

Q000917E

< CAUTION >

Never connect the wrong terminals of the connectors as this will lead to a malfunction.

Operation Section

1-85

Reading DTCs 1

• Turn the ignition switch ON and count the number of times the MIL (Malfunction Indicator Light) blinks

· Normal Operation

0.26sec

Repeat

Malfunction

OFF

Indicator Light

0.26sec

Jump Terminals TE1 and TC

· Malfunction (Codes "12" and "23" are output.)

0.52sec 1.5sec

2.5sec

1.5sec

4.5sec

Repeat Thereafter

OFF

0.52sec

Jump Terminals TE1 and TC

Q000918E

< NOTE >

• If the MIL (Malfunction Indicator Light) does not output a code (the light does not blink), there may be an open circuit in

the TC terminal system or a failure in the engine ECU.

• If the malfunction indicator light is constantly ON, there may be a short (pinching) in the wiring harness or a failure in

the engine ECU.

• If meaningless DTCs are output, there may be a malfunction in the engine ECU.

• If the MIL (Malfunction Indicator Light) illuminates without outputting a DTC while the engine operates at a minimum

speed of 1000rpm, turn the ignition switch OFF once; then resume the inspection.

Reading DTCs 2

• If an abnormal DTC has been output, check it against the DTC list.

Erasing DTCs from memory

• Remove the ECD fuse (15A); after 15 seconds have elapsed, re-install the fuse.

Engine Compartment Relay Block

ECD Fuse (15A)

Q000919E

< CAUTION >

After completing the inspection of the ECD system, erase the DTC memory, and make sure the normal code is output.

Operation Section

1-86

8.4 Throttle Body Function Inspection

< CAUTION >

• Be sure to inspect the function of the throttle body after it has been disassembled and reassembled, or after any of its

components have been removed and reinstalled.

• Verifying Throttle Motor: Verify that the motor generates an operating sound when the ignition switch is turned ON.

Also, verify that there is no interference sound.

(1) Erasing DTCs

1) Connect the DST-1 to the DLC3 connector.

DLC3

Q000914

2) Operate in accordance with the instructions shown on the

screen to display the "DTC check" screen. Select "Erase

DTC (ECD Erasure)

DTCs" to erase the DTCs.

This will erase the DTC and freeze frame data.

Do you wish to proceed?

NG : - OK : +

Q000916E

(2) Inspection

• Start the engine and make sure the MIL (Malfunction Indicator Light) does not illuminate and the engine speed is with-

in standards when the air conditioner is turned ON and OFF after the engine has warmed up.

< CAUTION >

Make sure no electrical load is applied.

(3) Final Inspection

• After inspecting the throttle body function, drive test the vehicle to confirm that operation is normal.

Operation Section

1-87

9. END OF VOLUME MATERIALS

9.1 Particulate Matter (PM)

z At high concentration levels, this substance is known to affect the respiratory system. It consists of soluble organic mat-

ter such as unburned oil, unburned diesel fuel, and other "soluble organic matter" in the exhaust gases, and insoluble

organic matter such as soot (black smoke) and sulfuric acid gas.

9.2 Common Rail Type Fuel Injection System Development History And

The World’s Manufacturers

z The conventional injection pump faced certain issues such as injection pressure that depended on engine speed, and

limits on the maximum fuel pressure. Other types of injection control such as pilot injection also faced some difficulties.

Addressing these issues in a revolutionary manner, DENSO led the world by introducing a commercial application of

the common rail fuel injection system.

z Two types of common rail fuel injection systems are in use today. One is the common rail system that pressurizes the

fuel and injects it directly into the cylinders. DENSO was the first in the world to introduce a commercial application of

this system. This system, which is undergoing further development, has been adopted in passenger car applications.

Other companies, such as R. Bosch, Siemens, and Delphi also offer their commercial versions of this system today. The

other system is the Hydraulic Electric Unit Injection (HEUI) system, which was developed by Caterpillar in the United

States. This system uses pressurized engine oil to pressurize the fuel by actuating the piston of the nozzle (injector)

through which the pressurized fuel is injected.

Operation Section

1-88

9.3 Higher Injection Pressure, Optimized Injection Rates, Higher Injection

Timing Control Precision, Higher Injection Quantity Control Precision

(1) Higher Injection Pressure

• The fuel that is injected from the nozzle turns into finer particles as the fuel injection pressure increases. This improves

combustion and reduces the amount of smoke contained in the exhaust gases. Initially, the maximum injection pres-

sure of the in-line pump (A type) and the distributor pump (VE type) was 60 MPa. Due to advancement in high-pres-

sure applications, there are some recently developed fuel injection systems that inject fuel at a pressure of 100 MPa

or higher. The second-generation common rail system injects fuel at an extremely high pressure of 180 MPa.

A Type Pump

Mechanical Pump

Distributor Type Pump

NB Type Pump

1 MPa is

ECD V3 Pump

approximately 10.2kgf/cm2

ECD V Series

ECD V4 Pump

120

(1st Generation)

HP0Pump

120

Common Rail Series

HP2Pump

145

(2nd Generation)

HP3,4Pump

185

100

150

200

Injection Pressure (MPa)

Q000920E

(2)

Optimized Injection Rates

•

The injection rate is the ratio of the changes in the fuel quantity that is injected successively from the nozzle within a

given unit of time.

Injection Rate

High Injection Rate

Q000921E

Operation Section

1-89

• As the injection pressure increases, the injection rate increases accordingly. The increase in injection rate leads to an

increase in the volume of the air-fuel mixture that is created between the start of injection until ignition (the ignition lag

period). Because this mixture is subsequently combusted at once, it creates noise (diesel knock) and NOx. For this

reason, it is necessary to appropriately control the injection rate by maintaining a low injection rate at the beginning

of injection and supplying a sufficient quantity after the ignition. To meet this need, two-spring nozzles have been

adopted and a pilot injection system has recently been developed.

2-Spring Nozzle

Common Rail System

Injection Rate

Injection Rate Control

Pilot Injection

Q000922E

(3) Higher Injection Timing Control Precision

• Reducing exhaust gas emissions and fuel consumption and optimizing the injection timing are important. It is ex-

tremely difficult to achieve the desired exhaust emission reduction levels through methods that adjust the injection

timing according to speed (or centrifugal force), such as the conventional mechanical timer. For this reason, electron-

ically controlled systems have been adopted to freely and precisely control the injection timing in accordance with the

engine characteristics.

Electronic Control Type

Mechanical Timer

Engine Speed

Q000923E

(4) Higher Injection Quantity Control Precision

• Power output adjustment in a diesel engine is accomplished by regulating the fuel injection quantity. Poor injection

quantity control precision leads to increased exhaust gas emissions, noise, and poor fuel economy. For this reason,

electronically controlled systems have been developed to ensure high precision injection quantity control.

Operation Section

1-90

9.4 Image Of Combustion Chamber Interior

z With conventional injection methods, because an excessive quantity of fuel was injected in the initial period, the explo-

sion pressure rose excessively, leading to the generation of noise such as engine knocking sounds. To improve this

condition through pilot injection, initially only the necessary and adequate quantity of fuel is injected. At the same time,

the combustion chamber temperature is raised, and main injection combustion is assisted while working to prevent

noise and vibration.

Conventional Injection

Pilot Injection

Q000924E

Repair Section

2-91

1. DIESEL ENGINE MALFUNCTIONS AND DIAGNOSTIC METH-

ODS (BASIC KNOWLEDGE)

1.1 Combustion State and Malfunction Cause

z Depending on the state of combustion in a diesel engine, diesel knock as well as the color of the exhaust gas may

change. Subsequently, the cause of engine malfunctions can be ascertained from changes in diesel knock and exhaust

gas color.

Knocking

Sound

White

Black

Smoke

Q002310E

(1) Diesel Knock

• When fuel mixed with air during the ignition lag period (from the time injection begins until the fuel is ignited) reaches

ignition temperature, the mixture is combusted in one burst. The pressure in the combustion chamber at this time rises

as the quantity of the air-fuel mixture increases. If a large amount of air-fuel mixture is created during the ignition lag

period, the pressure in the combustion chamber will rise rapidly. The pressure waves resulting from fuel ignition vi-

brate the cylinder walls and engine components, which generates noise. The generated noise is called "knocking".

To some extent, knocking is unavoidable in engines that use a self-ignition system.

Pressure Increase

Ignition

Start of

Injection

T.D.C. Crankshaft Angle

Q002311E

Cause of Diesel Knocking

A large quantity of air-fuel mixture is created prior to ignition, or the

Early Injection Timing

cetane value is high.

Cold Engine

Intake air temperature is low.

Ignition occurs late without an increase in temperature.

Poor Engine Compression

Poor Fuel Combustibility

Ignition occurs late (low cetane value.)

Repair Section

2-92

(2) White Smoke

White smoke: Uncombusted fuel that has been vaporized and then discharged.

• White smoke is generated when combustion occurs at a relatively low temperature, resulting in the exhaust of un-

combusted fuel and oil particles. White smoke is most likely to be generated when combustion chamber temperature

is low.

Source of White Smoke

Late Injection Timing

Fuel is injected when the piston is in the down stroke.

Cold Engine

Ignition occurs late and combustion is prolonged.

Poor Fuel Combustibility

Rise and Fall of Oil Pressure

Oil undergoes partial thermal breakdown.

(3) Black Smoke

Black smoke: Fuel that has been baked into soot and discharged.

• Black smoke is often referred to as just "smoke". Black smoke is generated when the injected fuel is poor in oxygen.

As the fuel is exposed to high temperatures, thermal breakdown occurs, leaving carbon behind. Black smoke occurs

when the injected fuel quantity is too large, or when the air-fuel mixture is rich due to an insufficient quantity of air.

Source of Black Smoke

Large Fuel Injection Quantity

Air-fuel mixture becomes rich.

Low Intake Air Quantity

Air quantity is insufficient due to air filter clogging.

Poor Fuel Atomization

The ratio of fuel to air worsens.

Retarded Fuel Injection Timing

Air-fuel mixing time is insufficient.

1.2 Troubleshooting

Troubleshooting cautions

z Observe the following cautions to avoid decreased engine performance and fuel injector malfunctions.

• Use the designated fuel.

• Avoid water and foreign material intrusion into the fuel tank.

• Periodically check and clean the filter.

• Do not unnecessarily disassemble sealed components.

Troubleshooting notes

z The cause of malfunctions is not necessarily limited to the pump itself, but may also be related to the engine and/or fuel

systems. Further, the majority of malfunctions are the result of user error, and often can often be resolved through simple

checks and maintenance. Avoid any hasty removal of system components.

Basic Check Items

Engine Oil

Fuel Supply to the Pump

Coolant

Injector Injection Status

Fan Belt

Supply Pump Timing Mark

Check for Loose or Disconnected Connectors, and

Air Cleaner

Modifications

Battery and Terminals

Idle Speed Status

Fuel System Leaks

Repair Section

2-93

2. DIAGNOSIS OVERVIEW

2.1 Diagnostic Work Flow

Diagnostic Procedures

Receive malfunctioning vehicle

Question the user to verify the nature of the

malfunction.

Does the malfunction reoccur?

Refer to "Actions for Non-Reoccurring Malfunc-

tions."

Verify the malfunction symptom at the actual

vehicle.

Use the DST-2 to check for any DTCs.

Proceed with diagnostics while referencing the

DTC chart in the repair manual for the appropri-

ate vehicle.

Use the DST-2 "Data Monitor" function to per-

Proceed with diagnostics while referencing the

form checks while monitoring each input and

repair manual for the appropriate vehicle.

output signal.

Use the DST-2 active test function to operate

Proceed with diagnostics while referencing the

each output device with the ignition switch in the

repair manual for the appropriate vehicle.

ON position. Check for any abnormalities in

either the electrical circuits or the output

devices.

Was the malfunction cleared?

Return to step 3.

Repair Section

2-94

2.2 Inquiries

z Use the Common Rail System (CRS) troubleshooting questionnaire to consult with the customer and adequately grasp

the malfunction symptoms.

< NOTE >

Do not ask random questions. Rather, ask questions that will aid in narrowing down the possible malfunctioning system

while making educated guesses based on the actual symptoms.

Questioning points

z Use the following questions as a basis to fully grasp the malfunction.

• What?: Malfunction symptoms

• When?: Date, time, frequency of occurrence

• Where?: Road conditions

• Under what conditions?: Driving conditions, engine operating conditions, weather

• How?: Impression of how the symptoms occurred.

CRS troubleshooting questionnaire

z When the vehicle is received at the service center, it is necessary to verify the "malfunction symptoms" and the "gener-

ated malfunction data" with the customer. Consult with the customer using the CRS troubleshooting questionnaire. The

troubleshooting questionnaire is necessary for the following reasons.

Reasons

• There are cases when the malfunction symptoms cannot be reproduced at the service center.

• The customer's complaint is not always limited to the malfunction.

• If the person performing repairs is not working from the correct malfunction symptoms, man-hours will be wasted.

• The questionnaire can aid the service center in diagnosing, repairing and verifying repair work.

Questioning Results

Inspection Results

Q002315E

Repair Section

2-95

(1) Questionnaire

CRS Troubleshooting Questionnaire

Vehicle Model

Receiving Date

Service History

No / Yes (

times)

Frame No.

Date Registered

Registration No.

Occurrence Date

Odometer Reading

Previous Vehicles Driven:

Main Area and Purpose of Use

Other Customer Information

Indications from the Customer

MIL Illumination No / Yes (

)

System Conditions

Driving Conditions

Road Surface

Other

Frequency of Occurrence

Occurrence Speed

During Take-Off

Flat

Accelerator

Normal

(

) km/hr

While Cruising

Uphill

Opening

Only Once

Shift Position

When Accelerating

Downhill

(

) %

Occasionally

(

) Range

When Decelerating

Dry, Sealed road

Outside Air

At Start-Up

When Braking

Wet, Sealed Road

Temperature

(

) Times per Day

Directly after Start-Up

When Turning

Unsealed Road or

(

) oC

(

) Times per Week

Up to (

) Minutes after Start

When Stopped

Rough Road Surface

Weather

(

) Times per Month

Questioning

Up to (

) Minutes into Driving

No Relationship

Snow-Covered or Icy Road

(

)

Results

When Cold

Other (

)

Potholes, Manholes, etc.

When Warm

Other (

)

During Operation

Other (

)

Additional Items

DTC Check

Illuminated

Yes

DTC Normal

Fuel Pressure when Engine is Stopped

Abnormal DTC (All Codes)

1 Minute after Turning Engine OFF

Malfunction Details: Time of occurrence, place and driving conditions during reoccurrence.

Inspection

Results

Reoccurrence

Continues to Appear

Occurs Regularly

Occurs Occasionally

Does Not Reoccur

Conditions

After One Occurrence

Q002316E

Repair Section

2-96

2.3 Non-Reoccurring Malfunctions

z In cases where the malfunction does not reoccur, perform the actions below to determine the cause of the malfunction.

Malfunction Symptom

Idle Speed,

Fully Dis-

Engine Stall,

Action

Engine will not

charged Bat-

Sputtering,

Start

tery

Poor Acceler-

ation

Verify that there is no DTC stored in the memory.

Yes

Use the questionnaire as a basis to perform a reoccurrence test in

"Reoccurrence" mode. Use this data (engine ECU voltage value, etc.)

Yes

to determine the cause of the malfunction.

Assume that an electrical sys-

tem wiring harness or connector

is the cause of the malfunction.

Yes

Shake the wiring by hand to

check whether a malfunction

Q002317

occurs and a DTC is generated.

Assume that an electrical system female connector terminal is the

cause of the malfunction and verify that the connection points are not

defective.

Yes

Recommended Tool: KOWA Precision Handling

Insert the male terminal that

Feeler Gauge Set (KLM-10-20)

matches the shape of the

Depending on the terminal, a matching

female terminal and check

size may not be available

for looseness.

Q002318

Use a dryer to heat the acceler-

ator pedal position sensor and

other electronic components.

Check for changes in the volt-

Q002319

age value (resistance value).

Yes

< CAUTION >

• Do not exceed 60°C (still touchable by hand) when heating.

• Do not remove the component cases and add heat directly to

electronic parts.

Verify whether malfunction symptoms occur under heavy engine

Yes

loads (headlights, A/C, wiper, etc. switches ON.)

If any commercial electrical products have been installed, remove

Yes

such products and verify whether the malfunction symptoms occur.

Repair Section

2-97

Malfunction Symptom

Idle Speed,

Fully Dis-

Engine Stall,

Action

Engine will not

charged Bat-

Sputtering,

Start

tery

Poor Acceler-

ation

If it is likely that the malfunction

Mist State

occurs in rainy or high-tempera-

ture weather, spray the vehicle

with water and verify whether

Q002320E

the malfunction occurs.

< CAUTION >

Yes

• Do not spray water directly into the engine compartment.

Spray water in mist form on all surfaces of the radiator to indi-

rectly change temperature and humidity.

• Do not spray water directly on electrical parts.

Repair Section

2-98

3. DTC READING (FOR TOYOTA VEHICLES)

3.1 DST-2

z The DST-2 can check for DTCs in either normal or check mode. In comparison to the normal mode, the check mode

has higher sensitivity in detecting malfunctions. Check mode is used when detection is not possible in normal mode,

regardless of the assumed abnormality.

3.2 DTC Check (Code Reading via the DST-2)

z Connect the DST-2 to the DLC3 connector.

z Operate the DST-2 in accordance with the instructions shown on the display to view the "DTC check" screen. Select

either the normal or check mode to verify the DTC.

3.3 DTC Memory Erasure (via the DST-2)

z To erase DTC codes, follow the instructions on the display to view the "DTC and Freeze Data Erasure" screen.

DTC (ECD Erasure)

This will erase the DTC and freeze frame data.

Do you wish to proceed?

NG : - OK : +

Q000916E

< CAUTION >

• If the DTC cannot be erased, cycle the ignition switch OFF and back ON, and then perform code erasure again.

• Do not use the DST-2 to erase the DTC until the cause of the malfunction is clear.

Repair Section

2-99

4. TROUBLESHOOTING BY SYSTEM

4.1 Intake System Diagnosis

Clogged air cleaner element

Clean or replace the air cleaner.

Check the suction path for leaks.

Repair or replace the malfunctioning compo-

• Suction path joints

nent.

• Suction pipes, hoses

Normal

4.2 Fuel System Diagnosis

Clogged air cleaner element

Fuel system check (remaining fuel quantity, fuel

Add fuel or replace components (clean tank.)

properties)

• Check the amount of fuel remaining in the

tank.

• Check the condition of the fuel. Request

engine analysis from a third party as neces-

sary.

- Color (no color, brownish, milky)

- Odor (kerosene, heavy oil, irritating odor)

- Separation of materials

(water, foreign

objects)

- Viscosity

(high/low viscosity, wax consis-

tency)

Repair Section

2-100

Fuel tank interior check (modification/additions,

Restore the fuel tank.

position of fuel pipe inlet/outlet, clogging and

holes)

• Check the tank for modifications or additions.

Consult with the user.

- Fuel inlet/outlet position, tank piping

- Foreign material inside the tank, water sep-

aration

- Tank-internal Zn cladding

- Check the tank-internal fuel piping for the

following.

- Inlet/outlet position (below position "E")

- Inlet clogging, bent or deformed piping

(crushed pipe)

- Crushed piping connections

Tank-external fuel path conditions

(crushed

Repair or replace the hose.

hose, clogging, air introduction at hose connec-

tion)

• Check the condition of the hose.

- Crushing around bands, over-bending

- Pinched or crushed by other parts

• Air introduction through fuel system connec-

tion points

- Looseness

- Hose deterioration (Verify by hand or visu-

ally that there is no rubber hardening/split-

ting.)

< CAUTION >

Be cautious when vacuum pressure is

present, as air will be drawn into the

hose.

Primary filter, sedimentor check

Replace the filter, and drain water from the sedi-

• Check for primary filter clogging and dirt.

mentor.

• Check sedimentor water volume.

Looseness at priming attachment point check

Tighten or replace the priming pump.

• Check the following.

- Looseness at the priming attachment point

- Does the piston stick out?

- Fuel leakage (oozing)

Repair Section

2-101

Filter (supply pump inlet) clogging

Clean the gauze filter, fuel filter and fuel piping

• Fuel filter

system, or replace the filters.

- Check for fuel delivery from the priming

pump.

• Gauze filter

- Visually check for clogging due to foreign

material.

Oil level increase (engine internal leak)

Check the engine.

• V erify whether the oil level increases on the

oil level gauge.

High-pressure piping and CRS component

Repair leaking high-pressure piping or replace

(injector supply pump, rail) fuel leaks (engine

leaking parts.

external leak) (Refer to "(2) Fuel leak check".)

• Connect the DST-2 to the diagnostic connec-

tor. Activate the "Fuel Leak Check Function"

within the active test.

• Visually check and specify areas that leak

fuel.

< CAUTION >

In the event of a large fuel leak down-

stream of the flow damper, be aware

that fuel flow will stop and the leak will

cease due to flow damper operation.

Normal

(1) Fuel pressure test procedure

• Connect the DST-2 to the vehicle-side test connector.

- With the vehicle idling, verify the rail pressure displayed on the DST-2.

System selection screen: Rail a ECU Data Monitor

Item Name (Abbrevi-

Explanation

Check Conditions

Reference Value

Items of Importance

ated)

During an Abnormal-

ity

Rail Pressure (RP)

• Displays the fuel

Following

engine

Fuel pressure in the

PCR1, PCR2 signals

pressure in the rail.

warm-up, when the

rail is displayed within

(rail assembly)

• Display range:

engine is rotating

a range of 30 MPa to

MPa to 255 MPa

160 MPa.

Repair Section

2-102

(2) Fuel leak check

• Connect the DST-2 to the vehicle-side test connector.

• With the vehicle idling, perform the active test by following the instructions on the DST-2 display.

System selection screen: TCCS a Active Test

Item Name

Description

Control Conditions

High-Pressure Fuel System Check

Raise engine speed to 2000 rpm, and

• Following engine warm-up, when

then use the active test to place the

the engine is at idle speed

fuel inside the rail under high pres-

• The vehicle speed sensor is operat-

sure.

ing normally, and speed is 0 km/h.

< CAUTION >

Engine speed cannot be

raised by stepping on the

accelerator pedal.

• Verify that there are no fuel system leaks during the active test (when fuel pressure is being applied to the rail.)

4.3 Basics of Electrical/Electronic Circuit Checks

(1) ECU terminal voltage and waveform measurements

• When measuring the voltage and resistance of each terminal, insert the multimeter probe into the rear side of the

wiring harness connector. If connectors are too small for the probe to be inserted easily, insert a fine metal wire into

the rear of the connector and touch the wire to the probe.

< NOTE >

The number of each terminal can be seen from the rear side of the wiring harness.

Engine ECU Side

Ground

Wiring Harness

Side

Ground

Q002326E

Repair Section

2-103

(2) Open circuit check

• When dealing with a wiring harness open circuit like that depicted in diagram 1, check continuity and/or voltage to

determine the location of the open circuit.

Diagram 1

Engine ECU

Open

Sensor

Circuit

Q002327E

Continuity Check

Remove connectors "A" and "C", and then measure resis-

Diagram 2

tance between the two.

Engine

Standard Value

1Ω or less

ECU

< NOTE >

Sensor

Measure resistance while gently shaking the wiring har-

ness up and down, and side-to-side.

Q002328E

As shown in diagram 2, there is no continuity (open circuit)

between terminal 1 of connector "A" and terminal 1 of con-

nector "C". However, there is continuity between terminal 2

of connector "A" and terminal 2 of connector "C". Therefore,

there is an open circuit between terminal 1 of connector "A"

and terminal 1 of connector "C".

Remove connector "B" and measure the connector resis-

Diagram 3

tance.

Engine

ECU

As shown in diagram 3, there is continuity between terminal

Sensor

1 of connector "A" and terminal 1 of connector "B1". Howev-

er, there is no continuity (open circuit) between terminal 1 of

connector "B2" and terminal 1 of connector "C". Therefore,

there is an open circuit between terminal 1 of connector "B2"

B2 B1

and terminal 1 of connector "C".

Q002329E

Repair Section

2-104

Voltage Check

For the circuit that applies voltage to the ECU connector ter-

Diagram 4

minals, check for an open circuit by performing a voltage

check.

As shown in diagram 4, with all connectors connected, mea-

5 V

0 V

sure the voltage for the ECU 5 V output terminal between

Sensor

5 V

the body ground and terminal 1 of connector "A". Next mea-

sure voltage for terminal 1 of connector "B" and terminal 1 of

connector "C" in the same fashion.

Q002330E

The faulty circuit and measurement results are shown be-

low.

• Voltage between terminal 1 of con-

nector "A" and the body ground is 5

• Voltage between terminal 1 of con-

Measurement

nector "B" and the body ground is 5

Results

• Voltage between terminal 1 of con-

nector "C" and the body ground is 0

There is an open circuit in the wiring

Faulty Item

harness between terminal 1 of connec-

tor "B" and terminal 1 of connector "C".

(3)

Short circuit check

•

As shown in diagram 5, if there is a short in the wiring harness ground, perform a "Ground Continuity Check" to de-

termine the cause of the short.

Diagram 5

Engine ECU

Short

Sensor

Circuit

Q002331E

Repair Section

2-105

Ground Continuity Check

Remove connector "A" and connector "C", and then mea-

Diagram 6

sure the resistance respectively between terminals 1 and 2

of connector "A" and ground.

Engine

ECU

Standard Value

1Ω or less

Sensor

< NOTE >

Measure resistance while gently shaking the wiring har-

ness up and down, and side-to-side.

Q002332E

As shown in diagram 6, there is continuity between terminal

1 of connector "A" and the body ground (short circuit). How-

ever, there is no continuity between terminal 2 of connector

"A" and the body ground. Therefore, there is a short circuit

between terminal 1 of connector "A" and terminal 1 of con-

nector "C".

Remove connector "B" and measure the resistance be-

Diagram 7

tween terminal 1 of connector "A" and the body ground, and

Engine

ECU

between terminal 1 of connector "B2" and the body ground.

Sensor

The faulty circuit and measurement results are shown be-

low.

Measurement

• There is no continuity between termi-

Results

nal 1 of connector "A" and the body

ground.

Q002333E

• There is continuity between terminal

1 of connector "B2" and the body

ground.

Faulty Item

There is a short circuit between terminal

1 of connector "B2" and terminal 1 of

connector "C".

Repair Section

2-106

(4) Connector connection fault verification method

• Simultaneously perform the data monitor and connector voltage measurements.

Ex.) Coolant temperature sensor

1. Read the "Coolant Temperature Output Voltage" value using the DST-2 data monitor.

2. Measure the voltage directly from the corresponding ECU terminal.

If "1" is unsatisfactory and "2" is satisfactory, the connector connection is judged as faulty.

Since some malfunctions only occur intermittently, measure voltage while pulling and shaking the

wires in order to try to get the malfunction to reoccur.

Voltage Measurement

No.2 - 34P

No.5 - 31P

137

143

162

167

Q002334E

Repair Section

2-107

5. TROUBLESHOOTING

5.1 Troubleshooting According to Malfunction Symptom (for TOYOTA Ve-

hicles)

(1) Malfunction Indicator Lamp (MIL) is lit.

Description

The check engine warning light is lit when the engine is running, or before the engine is started.

Possible Cause

The DTC is recorded in the engine ECU.

Clogged air cleaner element

Connect the DST-2 and read the DTC.

Inspect the check engine warning light circuit.

Troubleshoot the corresponding DTC.

(2) The engine is hard to start.

Description

The starter turns at normal speed, but the engine takes too long to start.

Possible Cause

• Start signal circuit

• Glow control system

• Crankshaft position sensor

• Engine ECU power supply circuit

• Injector

• Supply pump

• Cylinder recognition sensor

Clogged air cleaner element

Use the DST-2 to verify whether the coolant

Repair the glow control system. (Refer to the

temperature is at the glow system operating

glow control system check procedure issued by

temperature. In addition, verify whether battery

the vehicle manufacturer.)

voltage is being supplied to the glow plugs at

the designated times.

Use the DST-2 to monitor engine speed while

Check the crankshaft position sensor. (Refer to

cranking the engine. Verify whether engine

the crankshaft position sensor check procedure

speed is being correctly output.

issued by the vehicle manufacturer.)

Repair Section

2-108

Verify the output waveform of the cylinder rec-

Repair or replace the cylinder recognition sen-

ognition sensor. (Refer to the cylinder recogni-

sor and/or the corresponding circuit.

tion sensor check procedure issued by the

vehicle manufacturer.)

Check each injector. (Refer to the injector check

Repair or replace the injector and/or the corre-

procedure issued by the vehicle manufacturer.)

sponding circuit.

Verify whether there is a start signal when

Repair the start signal circuit.

cranking the engine by checking the engine

ECU start signal terminal.

Check the engine ECU power supply. (Refer to

Repair the engine ECU power supply.

the engine ECU power supply circuit diagram

issued by the vehicle manufacturer.)

Check the supply pump and the supply pump

Repair or replace the supply pump and drive cir-

drive circuit. (Refer to the supply pump drive cir-

cuit.

cuit diagram issued by the vehicle manufac-

turer.)

Troubleshooting complete

Repair Section

2-109

(3) The engine stalls when idling.

Description

The engine stalls after starting or when idling.

Possible Cause

• Crankshaft position sensor

• Engine ECU power supply circuit

• Injector

• Supply pump

• Engine cooling system

• Start signal circuit

Clogged air cleaner element

Verify that the engine is not overheated.

Repair the engine cooling system.

Check the crankshaft position sensor output

Repair or replace the crankshaft position sensor

waveform. (Refer to the crankshaft position sen-

and/or the corresponding circuit.

sor check procedure issued by the vehicle man-

ufacturer.)

Check each injector. (Refer to the injector check

Repair or replace the injector and/or the corre-

procedure issued by the vehicle manufacturer.)

sponding circuit.

Verify whether there is a start signal when

Repair the start signal circuit.

cranking the engine by checking the engine

ECU start signal terminal.

Check the engine ECU power supply. (Refer to

Repair the engine ECU power supply.

the engine ECU power supply circuit diagram

issued by the vehicle manufacturer.)

Check the supply pump and the supply pump

Repair or replace the supply pump and drive cir-

drive circuit. (Refer to the supply pump drive cir-

cuit.

cuit diagram issued by the vehicle manufac-

turer.)

Troubleshooting complete

Repair Section

2-110

(4) The engine cranks normally, but does not start.

Description

The engine is cranked at the normal speed, but does not start.

Possible Cause

• Crankshaft position sensor

• Engine ECU power supply circuit

• Injector

• Supply pump

• Start signal circuit

Clogged air cleaner element

Use the DST-2 to verify whether the coolant

Repair the glow control system. (Refer to the

temperature is at the glow system operating

glow control system check procedure issued by

temperature. In addition, verify whether battery

the vehicle manufacturer.)

voltage is being supplied to the glow plugs at

the designated times.

Monitor engine speed while cranking the

Check the crankshaft position sensor. (Refer to

engine. Verify whether engine speed is being

the crankshaft position sensor check procedure

correctly output.

issued by the vehicle manufacturer.)

Verify whether there is a start signal when

Repair the start signal circuit.

cranking the engine by checking the engine

ECU start signal terminal.

Check the engine ECU power supply. (Refer to

Repair the engine ECU power supply.

the engine ECU power supply circuit diagram

issued by the vehicle manufacturer.)

Check each injector. (Refer to the injector check

Repair or replace the injector and/or the corre-

procedure issued by the vehicle manufacturer.)

sponding circuit.

Check the supply pump and the supply pump

Repair or replace the supply pump and drive cir-

drive circuit. (Refer to the supply pump drive cir-

cuit.

cuit diagram issued by the vehicle manufac-

turer.)

Troubleshooting complete

Repair Section

2-111

(5) Idle instability following engine start

Description

Idle speed after starting the engine is abnormal.

Possible Cause

• Injector

• Supply pump

• Fuel filter

• Engine ECU

• Rail pressure sensor

Clogged air cleaner element

Check each injector. (Refer to the injector check

Repair or replace the injector and/or the corre-

procedure issued by the vehicle manufacturer.)

sponding circuit.

Check the fuel filter.

Replace the fuel filter.

Check the supply pump and the supply pump

Repair or replace the supply pump and drive cir-

drive circuit. (Refer to the supply pump drive cir-

cuit.

cuit diagram issued by the vehicle manufac-

turer.)

Check the rail pressure sensor and the corre-

Repair or replace the rail pressure sensor and

sponding circuit. (Refer to the rail pressure sen-

the corresponding circuit.

sor check procedure issued by the vehicle

manufacturer.)

Troubleshooting complete

Repair Section

2-112

(6) The engine returns to idle speed too slowly, or does not return at all.

Description

The time required for the engine to return to idle speed is longer than normal, or the engine does not return to idle

speed.

Possible Cause

• Accelerator position sensor

• Injector

• Supply pump

Clogged air cleaner element

Perform the accelerator pedal position sensor

Repair or replace the accelerator position sen-

function check. (Refer to the accelerator posi-

sor and/or the corresponding circuit.

tion pedal sensor check procedure issued by

the vehicle manufacturer.)

Check each injector. (Refer to the injector check

Repair or replace the injector and/or the corre-

procedure issued by the vehicle manufacturer.)

sponding circuit.

Check the supply pump and the supply pump

Repair or replace the supply pump and drive cir-

drive circuit. (Refer to the supply pump drive cir-

cuit.

cuit diagram issued by the vehicle manufac-

turer.)

Troubleshooting complete

Repair Section

2-113

(7) Rough idle

Description

Idle speed fluctuates, causing the engine to vibrate.

Possible Cause

• Engine cooling system

• Crankshaft position sensor

• Engine

• Supply pump

• Injector

Clogged air cleaner element

Check parts that may be a source of abnormal

Repair the engine.

engine vibration.

Check each injector. (Refer to the injector check

Repair or replace the injector and/or the corre-

procedure issued by the vehicle manufacturer.)

sponding circuit.

Verify that the engine is not overheated.

Repair the engine cooling system.

Check the crankshaft position sensor. (Refer to

Repair or replace the crankshaft position sensor

the crankshaft position sensor check procedure

and/or the corresponding circuit.

issued by the vehicle manufacturer.)

Check the supply pump and the supply pump

Repair or replace the supply pump and drive cir-

drive circuit. (Refer to the supply pump drive cir-

cuit.

cuit diagram issued by the vehicle manufac-

turer.)

Troubleshooting complete

Repair Section

2-114

(8) The engine stalls when decelerating.

Description

The engine suddenly stops when decelerating.

Possible Cause

• Engine cooling system

• Crankshaft position sensor

• Engine ECU power supply circuit

• Supply pump

• Injector

• Start signal circuit

Clogged air cleaner element

Verify that the engine is not overheated.

Repair the engine cooling system.

Check the crankshaft position sensor. (Refer to

Repair or replace the crankshaft position sensor

the crankshaft position sensor check procedure

and/or the corresponding circuit.

issued by the vehicle manufacturer.)

Check each injector. (Refer to the injector check

Repair or replace the injector and/or the corre-

procedure issued by the vehicle manufacturer.)

sponding circuit.

Verify whether there is a start signal when

Repair the start signal circuit.

cranking the engine by checking the engine

ECU start signal terminal.

Check the engine ECU power supply. (Refer to

Repair the engine ECU power supply.

the engine ECU power supply circuit diagram

issued by the vehicle manufacturer.)

Check the supply pump and the supply pump

Repair or replace the supply pump and drive cir-

drive circuit. (Refer to the supply pump drive cir-

cuit.

cuit diagram issued by the vehicle manufac-

turer.)

Troubleshooting complete

Repair Section

2-115

(9) Poor engine output, poor acceleration

Description

Deficient engine performance.

Possible Cause

• EGR system

• Injector

• Mass Air Flow (MAF) meter

• Crankshaft position sensor

• Accelerator position sensor

• Boost pressure sensor

• Supply pump

• Start signal circuit

• Air cleaner, duct

Clogged air cleaner element

Check for air cleaner clogging and/or damage.

Replace the air cleaner or repair the air duct.

Verify that the engine is not overheated.

Repair the engine cooling system.

Check the crankshaft position sensor. (Refer to

Repair or replace the crankshaft position sensor

the crankshaft position sensor check procedure

and/or the corresponding circuit.

issued by the vehicle manufacturer.)

Check each injector. (Refer to the injector check

Repair or replace the injector and/or the corre-

procedure issued by the vehicle manufacturer.)

sponding circuit.

Verify whether there is a start signal when

Repair the start signal circuit.

cranking the engine by checking the engine

ECU start signal terminal.

Check the MAF meter and the corresponding

Repair or replace the MAF meter and/or the cor-

circuit.

(Refer to the MAF meter check proce-

responding circuit.

dure issued by the vehicle manufacturer.)

DENSO COMMON RAIL SYSTEM (CRS). SERVICE MANUAL (2007) - page 3