DESCRIPTION
| Malfunction Condition | Main Trouble Area | Related Trouble Area |
|---|---|---|
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Specified values in the following troubleshooting flowchart are for reference only. Variations in the Data List values may occur depending on the measuring conditions or the vehicle age. Do not judge the vehicle to be normal even when the Data List values indicate a standard level. There are possibly some concealed factors of the malfunction.
Check that the vehicle has not been modified in any way prior to the vehicle inspection.
This troubleshooting procedure checks for the cause of a lack of engine power (e.g. the vehicle speed does not reach the target speed in the high speed range) while the vehicle is being driven.
Faults and Symptoms of Common Rail Diesel Components
Engine Control
| Component | Mass air flow meter | |
| Main fault | Decrease in performance (foreign matter is stuck) | |
| Symptoms | Lack of power, black smoke | |
| Data List | MAF | |
|
Tip:
The maximum fuel injection volume is controlled according to the output from the mass air flow meter. |
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| Component | Intake system | |
| Symptom: Main fault |
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| Data List |
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| Component | Turbocharger system | |
| Main fault |
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| Symptoms | Lack of power (when vehicle starting, when heavy load) (Black smoke is not emitted when racing while vehicle stopped) |
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| Data List | MAP (inside intake air pressure), Target Booster Pressure
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| Component | Exhaust system | |
| Main fault | Blockage | |
| Symptoms | Lack of power (high engine speed, when heavy load) | |
| Data List | MAP (inside intake air pressure), Target Booster Pressure When the accelerator is fully depressed, if MAP is 20 kPa lower than Target Booster Pressure for more than 5 seconds then a lack of power will be felt. |
|
| Component | Glow system | |
| Main fault | Open circuit, glow plug relay fault | |
| Symptoms | Difficult to start, rough idle, knocking, white smoke (when cold) | |
| Data List | Check the glow plug indicator light | |
| Diagnostic Point | Try to measure the resistance of the glow plug | |
| Component | Engine | |
| Main fault | Damaged, seized up | |
| Symptoms | Cannot crank, crank speed is low, strange noise | |
| Component | Engine | |
| Main fault | Loss of compression | |
| Symptoms | Rough idle (lack of power always) | |
| Data List | Engine Speed of Cyl#
Injection Feedback Val
|
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Diesel Injection
| Component | Fuel supply pump | |
| Main fault | - | |
| Symptoms | Difficult to start, engine stalling, rough idle, lack of power | |
| Data List | Fuel Press, Target Common Rail Pressure, Target Pump SCV Current
Tip:
|
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| Diagnostic Trouble Code | Even if Fuel Press is less than Target Common Rail Pressure, a DTC will not be stored. | |
| Component | Fuel filter | |
| Main fault | Blockage | |
| Symptoms | Difficult to start, engine stalling, rough idle, lack of power | |
| Data List | Fuel Press, Target Common Rail Pressure
Tip:
The fuel pressure changes at engine starting, but is approx. 25000 kPa at engine start after the engine is warmed up. |
|
| Diagnostic Trouble Code | Even if Fuel Press is less than Target Common Rail Pressure, a DTC will not be stored. | |
| Component | Fuel injector | |
| Main fault | Blockage | |
| Symptoms | Rough idle, lack of power, black smoke, white smoke, knocking | |
| Data List | Injection Feedback Val
|
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| Component | Pressure discharge valve | |
| Main fault | Does not completely close | |
| Symptoms | Difficult to start, engine stall, rough idle, lack of power | |
| Component | Injector Driver (EDU) | |
| Main fault | Circuit fault: The fuel injector does not open. | |
| Symptoms | Difficult to start, rough idle, lack of power, black smoke, white smoke, knocking | |
| Data List | Same as fuel injector | |
| Diagnostic Trouble Code | When the EDU has a fault, some DTCs may be stored. | |
| Component | Fuel pressure sensor | |
| Main fault | Open circuit, decrease in performance (foreign matter is stuck) | |
| Symptoms | Difficult to start, rough idle, engine stall, lack of power | |
| Data List | Fuel Press, Target Common Rail Pressure
|
|
| Diagnostic Code | When the fuel pressure sensor has a fault, some DTCs may be stored. | |
| Component | Irregular fuel | |
| Main fault | - | |
| Symptoms | Difficult to start, rough idle (especially when cold) | |
Diesel EGR
| Component | EGR system | |
| Main fault |
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| Symptoms |
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| Data List | Actual EGR Valve Pos., Target EGR Position
EGR Close Lrn. Val., EGR Close Lrn. Status
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Diesel Throttle
| Component | Diesel throttle system | |
| Main fault | Stuck, does not move smoothly | |
| Symptoms |
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| Data List |
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Data List Related to Lack of Power
The Data List values in the table are the results of checking one vehicle after warmed up. Only use these values for reference.
Engine Control
| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| Engine Speed | Idling: 720 to 820 rpm | Crankshaft position sensor | When the crankshaft position sensor is malfunctioning, "Engine Speed" is approximately 0 or varies greatly from the actual engine speed. |
| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| MAP | MAP (inside intake air pressure)
VN Turbo Command
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| Results of real-vehicle check:
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| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| MAF | - |
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| Results of real-vehicle check:
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Tip:
The maximum fuel injection volume is controlled according to the output from the mass air flow meter. |
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| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| Intake Air | After a long soak, the engine coolant temperature, intake air temperature and ambient air temperature are approximately equal. | Intake air temperature sensor | If the value is -40°C (-40°F) or 140°C (284°F), the sensor circuit is open or shorted. |
| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| Coolant Temp |
|
Engine coolant temperature sensor | If the value is -40°C (-40°F) or 140°C (284°F), the sensor circuit is open or shorted. |
Diesel Injection
| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| Target Common Rail Pressure | - | - |
|
| Results of real-vehicle check:
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| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| Fuel Press |
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| Results of real-vehicle check:
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| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| Target Pump SCV Current |
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With this data, component fault not specified, use this data as a reference |
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| Results of real-vehicle check:
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| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| Injection Feedback Val #1 (to #4) | Injection Feedback Val:
Tip:
Read the value after one minute of idling after warm up (engine coolant temperature above 70°C (158°F)). This value is only calculated when idling. |
|
With Injection Feedback Val, find the malfunctioning cylinders. However, before replacing the injector, identify the malfunctioning cylinders with a power balance test. |
| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| Injection Volume |
|
All cylinders | - |
| Results of real-vehicle check:
|
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Diesel Throttle
| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| Actual Throttle Position |
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Throttle valve | Actual Throttle Position is the closing percentage of the throttle valve.
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| Results of real-vehicle check:
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Diesel EGR
| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| Target EGR Position | - | - |
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| Results of real-vehicle check:
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| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
|---|---|---|---|
| Actual EGR Valve Pos. | Generally Actual EGR Valve Pos. = Target EGR Position +/-5% (completely closed = 0%, completely open = 100%). The EGR valve Active Test can be used to check whether Actual EGR Valve Pos. = Target EGR Position (take into consideration the temperature of the intake air and the coolant temperature when the malfunction occurs). Sometimes the malfunction only occurs around a certain temperature. Take into consideration the temperature of the intake air and the coolant temperature when the malfunction occurs. |
EGR valve | Inspect while comparing to "Target EGR Position". |
| Results of real-vehicle check:
|
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Examples of Actual Malfunctions
The purpose of the following examples is to help you to understand the relationship between each Data List item when a certain malfunction occurs. Understanding this relationship helps you to find the real root cause easier.
The following are examples of actual malfunctions of a common rail diesel engine.
Use them for reference when diagnosing malfunctions.
These are not data of the VERSO 2AD-FHV.
Lack of power caused by overly low boost pressure
Lack of power caused by overly low MAF
In this example, the MAF (Mass Air Flow) value decreases greatly due to foreign matter being stuck to the MAF meter and causes a lack of power. The maximum fuel injection volume value is limited by the MAF value. As a result, there is a lack of power due to a lack of injection volume.
In this case, even when the accelerator is fully open, the calculated load is low (Calculated Load = Injection Volume / Maximum Injection Volume at Current Engine Speed).
Basically, the Manifold Absolute Pressure (MAP) is approximately equal to the Target Booster Pressure and this indicates that the turbocharger functions properly.
EGR valve stuck in open position
In this example, the EGR valve is stuck in the open position. Even with the accelerator pedal fully depressed, the EGR does not fully close and the MAF signal is low.
Therefore, the fuel injection volume becomes limited and there is a lack of power. Jerking is also evident. At this time, even while accelerating with the accelerator fully open, the calculated load is low (Calculated Load = Current Injection Volume / Maximum Injection Volume at Current Engine Speed).
Basically, the Manifold Absolute Pressure (MAP) is approximately equal to Target Booster Pressure and this indicates that the turbocharger functions properly.
INSPECTION PROCEDURE
Explanation of Symptom
| Lack of Power | The power of the diesel engine is determined by the quantity of injected fuel and the quantity of intake air. The quantity of injected fuel is determined by the fuel pressure and the amount of time the injector is open for. Basically, the fuel pressure is controlled to reach the target fuel pressure. The throttle valve does not restrict air flow volume, so the manifold absolute pressure is almost the same as atmospheric pressure when idling. At more than approximately 1500 rpm, the turbo starts to operate causing the manifold absolute pressure to become higher than atmospheric pressure. The manifold absolute pressure is controlled to reach the Target Booster Pressure. Also, when accelerating the vehicle at full throttle, the throttle is fully open and the EGR valve is fully closed, preserving the mass air flow. |
Trouble Area Chart According to Problem Cause
After replacing the fuel supply pump, the ECM needs initialization (Click here).
After replacing a fuel injector, the ECM needs registration (Click here).
Before troubleshooting, conduct the following:
Check the fuel quality.
Check the fuel for air.
Check the fuel system for blockages.
Check the air filter.
Check the engine oil.
Check the engine coolant.
Check the engine idling speed and maximum engine speed.
PROCEDURE
READ OUTPUT DTC (RELATED TO ENGINE)
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / DTC.
Read pending DTCs.
| Result | Proceed to |
|---|---|
| No DTCs are output | A |
| Engine related DTCs are output | B |
TAKE SNAPSHOT DURING DRIVING TEST
Connect the intelligent tester to the DLC3.
Start the engine and turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data.
Take a snapshot of the following Data List items with the intelligent tester.
Driving pattern for the test should be decided based on customer's comment regarding the situation in which the problem occurred.
A snapshot can be used to compare vehicle data from the time of the malfunction to normal data and is very useful for troubleshooting. The data in the illustration below is that of a normal vehicle, but as the data varies between individual vehicles, this data should only be used for reference.
Graphs like the ones shown below can be displayed by transferring the stored snapshot from the tester to a PC. Intelligent Viewer must be installed on the PC.
Move the shift lever to 2nd gear and accelerate the vehicle with the accelerator fully open (obey all laws and regulations, and pay attention to driving conditions while driving the vehicle). Then, check the Data List with the engine warmed up and idling (the shift lever in neutral and A/C switch and all accessory switches off).
| Data List | Value | Unit |
|---|---|---|
| Vehicle Speed | 44 | km/h |
| Engine Speed | 3500 | rpm |
| Accel Position | 99.60 | % |
| Target Booster Pressure | 234.19 | kPa |
| MAP | 227 | kPa |
| MAF | 140.96 | g/sec. |
| Calculate Load | 100 | % |
| Target Common Rail Pressure | 194350 | kPa |
| Fuel Press | 189820 | kPa |
| Target Pump SCV Current | 1402.8 | mA |
| Injection Volume | 70.52 | mm3/st |
| VN Turbo Command | 44 | % |
| Actual EGR Valve Pos. | 0 | % |
| Actual Throttle Position | 0 | % |
| AF Lambda B1S1 | 1.167 | - |
| AFS Voltage B1S1 | 0.27 | V |
| Data List | Value | Unit |
|---|---|---|
| Engine Speed | 771 | rpm |
| Target Booster Pressure | 92.69 | kPa |
| MAP | 94 | kPa |
| MAF | 3.87 | g/sec. |
| Target Common Rail Pressure | 35000 | kPa |
| Fuel Press | 33640 | kPa |
| Injection Volume | 5.15 | mm3/st |
| VN Turbo Command | 57 | % |
| Actual EGR Valve Pos. | 54.1 | % |
| Target EGR Position | 54.1 | % |
| Actual Throttle Position | 93 | % |
| Accel Position | 0.00 | % |
| Injection Feedback Val #1 | 0.0 | mm3/st |
| Injection Feedback Val #2 | -0.5 | mm3/st |
| Injection Feedback Val #3 | 0.0 | mm3/st |
| Injection Feedback Val #4 | 0.1 | mm3/st |
| Atmosphere Pressure | 100 | kPa |
| Coolant Temp | 76 | °C |
Examples of Actual Malfunctions (See "Diagnostic Help" menu)
Lack of power caused by overly low boost pressure
Lack of power caused by overly low MAF
EGR valve stuck in open position
For engine protection, exhaust gas or fuel economy related reasons, there are some ranges of engine operation where engine power feels like it flattens out, but this is not a malfunction.
Check for a lack of power during the driving test.
| Result | Proceed to |
|---|---|
| Apparent lack of power is present | A |
| Apparent lack of power is not present | B |
CHECK SNAPSHOT
Check the condition of the vehicle using the snapshot taken during the lack of power.
| Result | Proceed to |
|---|---|
| Fuel Press is less than "Target Common Rail Pressure - 20000 kPa" when accelerating with accelerator fully open | B |
| Target Pump SCV Current 3000 mA or more | C |
| One of the Injection Feedback Val #1 to 4 values is outside the range of +/-3 mm3/st when idling after warm up |
D |
| Injection Feedback Val #1 to #4 is within the range of +/-3 mm3/st and Injection Volume is more than 10 mm3/st when idling after warm up |
E |
| None of the above conditions apply | A |
CHECK SNAPSHOT
Check the condition of the vehicle using the snapshot taken during the lack of power.
| Result | Proceed to |
|---|---|
| MAP is less than "Target Booster Pressure - 20 kPa" (MAF is normal) when accelerating with accelerator fully open | A |
| MAF is low when accelerating with accelerator fully open (MAP is normal)
Tip:
If MAF (Mass Air Flow) decreases, Calculate Load will be 80% or less when accelerating with the accelerator fully open. |
B |
| MAP and MAF are both low when accelerating with the accelerator fully open | C |
| None of the above conditions apply | D |
When racing the engine, if the boost pressure becomes less than atmospheric pressure, there may be blockage in the intake system, or the turbocharger shaft may be stuck.
INSPECT VACUUM HOSE
Check the vacuum hose connection (manifold absolute pressure sensor).
| OK |
|---|
| Vacuum hose is connected securely. |
READ VALUE USING INTELLIGENT TESTER (MAP AND ATMOSPHERE PRESSURE)
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / MAP and Atmosphere Pressure.
Compare MAP to Atmosphere Pressure when the ignition switch is ON (engine stopped).
If MAP and Atmosphere Pressure have the same value, both are normal. If there is a difference of 10 kPa or more, compare the values to the atmospheric pressure for that day. The sensor whose deviation is the greatest is malfunctioning.
Standard atmospheric pressure is 101 kPa. For every 100 m increase in altitude, pressure drops by 1 kPa. Varies by weather (high atmospheric pressure, low atmospheric pressure).
| Result | Proceed to |
|---|---|
| Atmosphere Pressure is different from actual atmospheric pressure | A |
| MAP is different from actual atmospheric pressure | B |
| MAP and Atmosphere Pressure have the same value | C |
CHECK MASS AIR FLOW METER
Check the mass air flow meter (Click here).
CHECK EGR VALVE ASSEMBLY
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / EGR Close Lrn. Status.
Read the values.
| Standard |
|---|
| EGR Close Lrn. Status is OK |
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.
When changing the Active Test continuously value to 0, 30, 60, 90, 60, 30 and 0%, check that Actual EGR Valve Pos. smoothly changes to the set opening angle.
| OK |
|---|
| Value smoothly changes to set opening angle. |
Remove the EGR valve assembly (Click here).
Visually check the electric EGR control valve for deposits.
If there are deposits, clean the electric EGR control valve.
When cleaning the electric EGR control valve, make sure the valve is completely closed.
Do not forcibly open the valve, as it may be damaged or deformed.
When cleaning the electric EGR control valve, use a piece of cloth soaked with cleaning solvent. Spraying the solvent directly onto these parts or soaking the parts in solvent may damage the parts.
Hold the electric EGR control valve up to a light, and then from the side indicated by the arrow in the illustration, visually check that there is no gap between the valve and body.
| OK |
|---|
| No light passes through (there is no gap between the valve and body). |
If light passes through (there is a gap between the valve and body), replace the electric EGR control valve assembly.
Light passes through part A shown in the illustration even if the valve is completely closed. This is not a problem.
READ VALUE USING INTELLIGENT TESTER (ACCEL POSITION)
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Accel Position.
Read the value.
| Standard Value | ||||||||
|---|---|---|---|---|---|---|---|---|
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CHECK DIESEL THROTTLE BODY ASSEMBLY
Check the diesel throttle body assembly (Click here).
CHECK INTAKE SYSTEM
Check for air leakage and blockage between the air cleaner and turbocharger, and between the turbocharger and intake manifold.
Check that the intercooler is not clogged with foreign matter.
Check that there are no disconnected, pinched or leaking hoses or pipes.
Check that there are no modifications made by the user.
| OK |
|---|
| No leakage or blockage. |
INSPECT TURBOCHARGER SUB-ASSEMBLY
Inspect the turbocharger sub-assembly (Click here).
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
Check whether the lack of power has been successfully repaired.
| OK |
|---|
| Malfunction has been repaired successfully. |
Symptoms may have appeared due to carbon deposits, etc.
BLEED AIR FROM FUEL SYSTEM
Bleed the air from the fuel system (Click here).
PERFORM ACTIVE TEST USING INTELLIGENT TESTER (TEST THE FUEL LEAK)
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Test the Fuel Leak / Data List / Fuel Press, Target Common Rail Pressure, and Target Pump SCV Current.
Take a snapshot with the intelligent tester during the Active Test.
Detailed graphs can be displayed by transferring the stored snapshot from the tester to a PC (personal computer) with Intelligent Viewer installed.
Measure the difference between the target fuel pressure (Target Common Rail Pressure) and the actual fuel pressure (Fuel Press) when the "Test the Fuel Leak" Active Test is performed.
In order to obtain an exact measurement, perform the Active Test 5 times and measure the difference once each time the Active Test is performed.
| OK |
|---|
| The difference between the target fuel pressure and the actual fuel pressure 2 seconds after the Active Test starts is less than 10000 kPa. |
"Target Common Rail Pressure" means target fuel pressure controlled by the ECM.
"Fuel Press" means actual fuel pressure.
When the Active Test "Test the Fuel Leak" is used to change the pump control mode, the actual fuel pressure inside the common rail drops below the target fuel pressure when the Active Test is off, but this is normal and does not indicate a pump malfunction.
If the pressure discharge valve mounted on the common rail is malfunctioning, the actual fuel pressure will change as indicated by "Pressure Discharge Valve Malfunctioning" in the illustration.
| Result | Proceed to |
|---|---|
| Difference between target fuel pressure and actual fuel pressure is less than 10000 kPa | A |
| Difference between target fuel pressure and actual fuel pressure is 10000 kPa or more | B |
INSPECT COMMON RAIL ASSEMBLY
Inspect the common rail assembly (Click here).
CHECK HARNESS AND CONNECTOR (SUCTION CONTROL VALVE - ECM)
Disconnect the suction control valve connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance (Check for Open) | |||||||||
|---|---|---|---|---|---|---|---|---|---|
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| Standard Resistance (Check for Short) | |||||||||
|---|---|---|---|---|---|---|---|---|---|
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| *1 | Front view of wire harness connector (to Suction Control Valve) |
| *2 | Front view of wire harness connector (to ECM) |
Reconnect the suction control valve connector.
Reconnect the ECM connector.
CHECK IF FUEL IS BEING SUPPLIED TO FUEL SUPPLY PUMP
Disconnect the inlet hose from the fuel supply pump.
Operate the priming pump and check that fuel is being supplied to the fuel supply pump.
| OK |
|---|
| Fuel is properly supplied to the fuel supply pump when the priming pump is operated. |
When lack of fuel, fuel pressure drops.
Inspect for fuel filter clogging.
(Check that the fuel filter is not clogged)
REPLACE SUCTION CONTROL VALVE
Replace the suction control valve (Click here).
BLEED AIR FROM FUEL SYSTEM
Bleed the air from the fuel system (Click here).
PERFORM FUEL SUPPLY PUMP INITIALIZATION
Perform fuel supply pump initialization (Click here).
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
Check whether the lack of power has been successfully repaired.
Fuel Press is within +/-5000 kPa of Target Common Rail Pressure.
READ VALUE USING INTELLIGENT TESTER (CATALYST DIFFERENTIAL PRESS)
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the tester on.
Start the engine and drive the vehicle until the engine coolant temperature reaches 60°C (140°F) or higher.
Enter the following menus: Powertrain / Engine and ECT / Data List / Catalyst Differential Press.
Check the differential pressure at an engine speed of 3000 rpm with no load.
| Standard |
|---|
| Catalyst Differential Press is less than 0.25 |
With the vehicle stopped, fully depress the accelerator pedal for 5 seconds and then release it.*A
Repeat procedure *A 10 times.*B
Check for black smoke emission during the above procedures *A and *B.
| Standard |
|---|
| Black smoke is emitted less than 5 times. |
Even if the black smoke is very thin, count the black smoke emission if there is any visible smoke.
| Differential Pressure (kPa) | Proceed to | Note |
|---|---|---|
| Catalyst Differential Press 0.25 or more at 3000 rpm (No engine load) |
B | An extremely large amount of PM (Particulate Matter) has accumulated in the DPNR catalyst. |
| Black smoke is emitted 5 times or more | B | The DPNR catalyst cannot trap PM because it is melted or cracked, and therefore must be replaced. Also, if a piece of the catalyst breaks off, due to melting or another condition, and enters the exhaust pipe downstream, the exhaust pipe could be blocked, possibly causing a different malfunction. Therefore, when replacing the DPNR catalyst, visually inspect the rear surface of the DPNR filter substrate to determine if replacement of the exhaust pipe is necessary. |
| Except above | A | - |
If the "Catalyst Differential Press" is more than about 0.4, DTC P2002 (Particulate Trap Efficiency Below Threshold [Bank 1]) will be stored.
The standard for the differential pressure sensor output is as follows:
| Condition | Differential Pressure Output |
|---|---|
| Ignition switch ON | Approximately 0 kPa |
If the Differential Pressure output is always 3 kPa, an open or short may exist in the differential pressure sensor circuit.
If the Differential Pressure outputs a negative value when the engine is maintained at an engine speed of 3000 rpm with no load, the hose and pipe connections may be incorrect.
CHECK TEMPERATURE WHEN LACK OF POWER OCCURS
Check the temperature when the lack of power occurs.
| Result | Proceed to |
|---|---|
| Poor acceleration only when engine is cold | A |
| Poor acceleration when engine is cold and warm | B |
INSPECT ENGINE COOLANT TEMPERATURE SENSOR
Inspect the engine coolant temperature sensor (Click here).
After warming up the engine, the engine coolant temperature should be 70°C (158°F) or more. After leaving the vehicle overnight, the engine coolant temperature should be nearly equal to the intake air temperature.
INSPECT GLOW PLUG ASSEMBLY (RESISTANCE)
Inspect the glow plug assembly (Click here).
INSPECT INJECTOR COMPENSATION CODE
Read the injector compensation codes (Click here).
| OK |
|---|
| Compensation codes stored in the ECM match the compensation codes of the installed fuel injectors. |
CHECK FUEL QUALITY
Check that fuel with a low cetane number is used.
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
Check whether the lack of power has been successfully repaired by starting the engine.
INSPECT INJECTOR COMPENSATION CODE
Read the injector compensation codes (Click here).
| OK |
|---|
| Compensation codes stored in the ECM match the compensation codes of the installed fuel injectors. |
PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE CYLINDER #1 TO #4 FUEL CUT)
Use this Active Test to determine the malfunctioning cylinder.
Connect the intelligent tester to the DLC3.
Start the engine and turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Cylinder #1 to #4 Fuel Cut.
If the engine idle speed does not change when a fuel injector is disabled, the cylinder being tested is malfunctioning.
If the cylinder being tested is normal, there will be a significant change in idle speed when the fuel injection is stopped for that cylinder.
PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CHECK THE CYLINDER COMPRESSION)
Use this Active Test to help determine whether a cylinder has compression loss or not.
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Check the Cylinder Compression / Data List / Compression / Engine Speed of Cyl #1 to #4.
Check the engine speed during the Active Test.
| OK |
|---|
| The values of Engine Speed Cyl #1 to #4 are within +/-10 rpm of each other. |
When cranking, if the speed of a cylinder is approximately 100 rpm more than the other cylinders, there is probably a loss of compression in that cylinder.
CHECK CYLINDER COMPRESSION PRESSURE OF MALFUNCTIONING CYLINDER
Measure the compression of the cylinder that had a high speed during the Active Test "Check the Cylinder Compression".
Check the cylinder compression pressure (Click here).
REPLACE FUEL INJECTOR OF MALFUNCTIONING CYLINDER
The injector is determined to be faulty as the corresponding cylinder is malfunctioning, but has no compression loss.
Replace the fuel injector of the malfunctioning cylinder (Click here).
BLEED AIR FROM FUEL SYSTEM
Bleed the air from the fuel system (Click here).
REGISTER INJECTOR COMPENSATION CODE AND PERFORM PILOT QUANTITY LEARNING
Register the injector compensation code (Click here).
Perform the fuel injector pilot quantity learning (Click here).
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
CHECK INTAKE SYSTEM DEPOSIT
Check carbon is accumulating on the intake manifold, cylinder head, etc. and if so, clean it off.
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
Symptoms may have appeared due to carbon deposits, etc.
REPLACE FUEL INJECTORS OF ALL CYLINDERS
Replace the fuel injectors (Click here).
BLEED AIR FROM FUEL SYSTEM
Bleed the air from the fuel system (Click here).
REGISTER INJECTOR COMPENSATION CODE AND PERFORM PILOT QUANTITY LEARNING
Register the injector compensation codes (Click here).
Perform registration of the fuel injector pilot quantity learning values (Click here).
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
CHECK AND REPLACE CLOGGED FUEL PIPE (INCLUDING FUEL FREEZING) (FUEL TANK - FUEL SUPPLY PUMP)
Check and replace clogged the fuel pipe.
BLEED AIR FROM FUEL SYSTEM
Bleed the air from the fuel system (Click here).
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
REPLACE COMMON RAIL
Replace the common rail (Click here).
BLEED AIR FROM FUEL SYSTEM
Bleed the air from the fuel system (Click here).
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
END
GO TO DTC CHARTClick here
REPLACE VACUUM HOSE
REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR
REPLACE MASS AIR FLOW METERClick here
REPLACE EGR VALVE ASSEMBLYClick here
REPLACE ACCELERATOR PEDAL ROD ASSEMBLYClick here
REPLACE DIESEL THROTTLE BODY ASSEMBLYClick here
REPAIR OR REPLACE MALFUNCTIONING PARTS
REPLACE TURBOCHARGER SUB-ASSEMBLYClick here
REPLACE MONOLITHIC CONVERTER ASSEMBLYClick here
REPLACE ENGINE COOLANT TEMPERATURE SENSORClick here
REPLACE GLOW PLUG ASSEMBLYClick here
CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
REPLACE ECMClick here
REPAIR OR REPLACE HARNESS OR CONNECTOR
COMPARE WITH SIMILAR VEHICLE WITH SAME ENGINE
Confirm the situation in which the lack of power was experienced by the customer again, and compare the driving feeling under the same conditions using a similar vehicle with the same engine while collecting data with the intelligent tester.
Confirm the state of the following conditions when the lack of power was experienced.
Accelerator pedal position (vehicle load)
Vehicle speed
Engine coolant temperature
Atmospheric temperature
Driving conditions before the lack of power occurred
Climate
Road and traffic conditions
When (what day) the problem was noticed
Whether the problem occurs suddenly or gradually
How often the problem occurs
Why the customer felt there is a lack of power (e.g. the customer compared their vehicle with another vehicle, somebody told the customer that their vehicle has a lack of power)
Level of lack of power (slight or drastic)
| Result | Proceed to |
|---|---|
| Significant difference is found | A |
| Significant difference is not found | B |
EXPLAIN THE INVESTIGATION RESULT TO CUSTOMER
Vehicle performance is normal.
There is no problem at this point in time. However, if the problem recurs, ask the customer to explain in detail the situation in which the problem occurred.
The best course may be to have the customer ride in another vehicle with the same specifications to understand that there is no problem with the customer's vehicle.
END