ECD SYSTEM (w/o DPF) Engine Difficult to Start or Stalling

DESCRIPTION

Faults and Symptoms of Common Rail Diesel Components

Engine Control

Mass Air Flow Meter
Component		Mass air flow meter
Main fault		Decrease in performance (foreign matter is stuck)
Symptoms		Lack of power, black smoke
Data List		MAF
Tech Tips The maximum fuel injection volume is controlled according to the output from the mass air flow meter.

Intake System
Component		Intake system
Symptom: Main fault		Lack of power (No black smoke): Air filter blockage, Air duct is crushed/leaking Black smoke (No lack of power): Leakage between the turbo and the intake manifold
Data List		MAP (inside intake air pressure) Target Booster Pressure When the accelerator is fully depressed, if the MAP is 20 kPa lower than Target Booster Pressure for more than 5 seconds then a lack of power will be felt.

Turbocharger System
Component		Turbocharger system
Main fault		Air leak in the turbocharged air passage Turbo motor driver not operating well Turbocharger (turbine, bearing)
Symptoms		Lack of power (when vehicle starting, when heavy load) (Black smoke is not emitted when racing while vehicle stopped)
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. With the ignition switch ON or idling, MAP = Atmospheric Pressure (standard atmospheric pressure = 101 kPa). When the engine speed is about 1500 rpm or more, the turbocharger starts to take effect and the MAP becomes higher than atmospheric pressure. Atmospheric pressure increases 1 kPa each time altitude increases by 100 m, and is also affected by the current weather conditions. VN Turbo Command 0%: Fully open vanes (drive rod contracts) Over 90%: Fully closed (drive rod expands and turbo operates effectively)
Diagnostic Point		Using the Active Test "Test the Turbo Charger Step Motor", check the drive rod movement. Check the drive rod movement when the ignition switch is turned from ON to off.

Exhaust System
Component		Exhaust system
Main fault		Blockage
Symptoms		Lack of power (high engine speed, when heavy load)
Data List		MAP (inside intake air pressure) When the accelerator is fully depressed, if the MAP is 20 kPa lower than Target Booster Pressure for more than 5 seconds then a lack of power will be felt.

Glow System
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

Battery
Component		Battery
Main fault		Battery is depleted
Symptoms		Difficult to start (cannot crank, crank speed is low), horn is quiet.
Data List		Battery Voltage When cranking, battery voltage is less than 5 V

Engine - 1
Component		Engine
Main fault		Damaged, Seized up
Symptoms		Cannot crank, crank speed is low, strange noise

Engine - 2
Component		Engine
Main fault		Loss of compression
Symptoms		Rough idle (lack of power always)
Data List		Engine Speed of Cyl When cranking during the "Check the Cylinder Compression" Active Test, if there is a high speed cylinder, approx. 100 rpm more than the other cylinders, that cylinder may loose compression. Injection Feedback Val If Injection Feedback Val is more than 3 mm³/st, the cylinder may have a fault.

Start System
Component		Entry and Start system
Main fault		Starter system malfunction
Symptoms		Difficult to start
Data List		Starter Signal Ignition switch (STA) operation ON: Starter is operating OFF: Starter is not operating

Immobiliser system
Component		Engine immobiliser system
Main fault		Engine immobiliser system/Problem Symptoms Table Click here
Symptoms		Engine does not start
Data List		Immobiliser Communication ON: Normal OFF: GND short or immobiliser is set Engine Immobiliser System/Data List Click here

Diesel Injection

Fuel Supply Pump
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 At a stable condition (e.g. Idling), Fuel Press is within +/-5000 kPa of "Target Common Rail Pressure". If the fuel pressure is 20000 kPa below the target pressure then a lack of power will be felt. If the fuel pressure is below 25000 kPa then idling will be rough. Tech Tips The fuel pressure changes at engine starting, but is approx. 25000 kPa at engine start after the engine is warmed up. When Target Pump SCV Current is 3000 mA or more, the suction control valve has a tendency to become stuck.
Diagnostic Trouble Code		Even if Fuel Press is less than Target Common Rail Pressure, a DTC will not be stored.

Fuel Filter
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 At a stable condition (e.g. Idling), the fuel pressure is within +/-5000 kPa of "Target Common Rail Pressure ". If the fuel pressure is 20000 kPa below the target pressure then a lack of power will be felt. If the fuel pressure is below 25000 kPa then idling will be rough. Tech Tips 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.

Fuel Injector
Component		Fuel injector
Main fault		Blockage
Symptoms		Rough idle, lack of power, black smoke, white smoke, knocking
Data List		Injection Feedback Val When an Injection Feedback Val is more than 3 mm³/st, the cylinder is not normal. This can be read after idling for 1 minute with the engine warmed up (engine coolant temperature is more than 70°C (158°F)).

Pressure Limiter
Component		Pressure limiter
Main fault		Does not completely close
Symptoms		Difficult to start, engine stall, rough idle, lack of power

Injector Driver (EDU)
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.

Fuel Pressure Sensor
Component		Fuel pressure sensor
Main fault		Open circuit, Decrease in performance (foreign matters is stuck)
Symptoms		Difficult to start, rough idle, engine stall, lack of power
Data List		Fuel Press, Target Common Rail Pressure Slowly raise the engine speed from idling to 3000 rpm with the vehicle stopped, and check that Fuel Press follows Target Common Rail Pressure. If the fuel pressure sensor malfunctions, the actual fuel pressure may deviate from the target fuel pressure. (However, the value may not deviate even when a malfunction is present).
Diagnostic Trouble Code		When the fuel pressure sensor has a fault, some DTCs may be stored.

Irregular Fuel
Component		Irregular fuel
Main fault		-
Symptoms		Difficult to start, rough idle (especially when cold)

Diesel EGR

EGR System
Component		EGR system
Main fault		Does not move smoothly Does not close completely
Symptoms		Rough idle EGR valve stuck closed: A loud turbocharger sound. EGR valve stuck open: Difficult to start (does not stall), black smoke, lack of power (if there is an excess in the quantity of EGR and there is a heavy load, when the vehicle starts moving, a lack of power will be felt).
Data List		Actual EGR Valve Pos., Target EGR Pos. Generally, Actual EGR Valve Pos. = Target EGR Pos. +/-5% (fully closed 0%, fully open 100%) Using EGR valve Active Test, check whether Actual EGR Valve Pos. follows Target EGR Pos. (The engine coolant temperature and intake air temperature should be considered when a malfunction occurs). EGR valve is fully closed when the ignition switch is ON (engine stopped). EGR valve opens to halfway point at idling after engine warmed up. EGR Close Lrn. Val., EGR Close Lrn. Status Leaving the vehicle idling, when EGR Close Lrn. Status is OK, the normal range of EGR Close Lrn. Val. is 3.5 to 4.5 V. In cases when EGR Close Lrn. Status. is NG or EGR Close Lrn. Val. is out of the normal range (3.5 to 4.5 V), it is possible that the EGR valve cannot completely close.

Diesel Throttle

Diesel Throttle System
Component		Diesel throttle system
Main fault		Stuck, does not move smoothly
Symptoms		Stuck closed: Lack of power, difficult to start, rough idle, engine stall, black smoke. It may occur when stuck almost fully closed. Stuck open: Turbocharger sound increases. When the engine is stopped, engine vibrations may occur.
Data List		Actual Throttle Position, Actual Throttle Position #2 0%: Fully open 100%: Fully closed Throttle Motor Duty Normally operates at 50 +/-20%. If outside the range of 50 +/-40% for a few seconds, the throttle may not be sliding properly. 0%: Open diesel throttle 100%: Close diesel throttle When ignition switch is ON (engine stopped), diesel throttle is fully open. When idling, diesel throttle is at halfway point. When ignition switch is turned from ON to off, temporarily closed fully.

Data List Related to Starting Trouble

Note

The Data List values in the table are the results of checking one vehicle under a specific condition (engine coolant temperature, intake air temperature, atmosphere pressure etc.). That is why use these values for reference only.

Engine Control

MAP
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
MAP	When MAP is low, there will be difficulty starting. With ignition switch ON or idling, MAP is nearly equal to Atmosphere Pressure (standard atmospheric pressure = 101 kPa).	When MAP is low, the following conditions are possible: The diesel throttle is nearly fully closed. Intake system blocked (turbocharger system also). Exhaust system blocked.	When the ignition switch is ON or the vehicle is idling, MAP (intake manifold absolute pressure) and Atmosphere Pressure are mostly the same (standard atmospheric pressure = 101 kPa). Above approx. 1500 rpm, the turbo becomes effective, and the pressure becomes higher than atmospheric pressure. Inspect while comparing with "Target Booster Pressure". With the accelerator fully open, if the actual Manifold Absolute Pressure (MAP) is low compared to the target booster pressure by at least 20 kPa for 5 seconds or more, a feeling of insufficient power will occur.
MAP	Results of real-vehicle check: Ignition switch ON: 99 kPa Cranking: 99 kPa Idling (warm up the engine): 99 kPa (2 minutes after starting the vehicle) Running without load (2500 rpm): 113 kPa Driving with the accelerator fully open at 2000 rpm: 143 kPa Driving with the accelerator fully open at 3000 rpm: 209 kPa

MAF
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
MAF	-	MAF meter MAF meter circuit Intake system clogging, leaking Exhaust system clogging Turbocharger sub-assembly Leaking or clogging of turbocharger passages EGR valve does not close	Based on the MAF, the ECM controls the fuel injection volume, injection timing, EGR, etc. If the value is always approximately 0 g/sec.: Mass air flow meter power source circuit is open. VG circuit is open or shorted. If the value is always 200 g/sec. or more: EVG circuit is open.
	Results of real-vehicle check: w/ EGR Ignition switch ON: 1.54 g/sec. Cranking: 15 g/sec. Idling (warm up the engine): 9 g/sec. (2 minutes after starting the vehicle) Running without load (2500 rpm): 80 g/sec. Driving with the accelerator fully open at 2000 rpm: 110 g/sec. Driving with the accelerator fully open at 3000 rpm: 230 g/sec.
	Tech Tips The maximum fuel injection volume is controlled according to the output from the mass air flow meter.

Intake Air
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Intake Air	-	Intake air temperature sensor.	After a long soak, the engine coolant temperature, intake air temperature, and ambient air temperature are approximately equal. If the value is -40°C (-40°F) or 140°C (284°F), the sensor circuit is open or shorted.
Intake Air	-

Coolant Temp
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Coolant Temp	Engine coolant temperature is approximately equal to intake air temperature after leaving overnight. After warm-up: Engine coolant temperature is 70°C (158°F) or more. In cases when the engine coolant temperature output is obviously higher than the actual engine coolant temperature, when it is cold, there will be difficulty starting due to problems with glow plugs or insufficient fuel injection. In cases when the engine coolant temperature sensor output is obviously lower than the actual engine coolant temperature, when it is warm, there will be difficulty starting (black smoke will also occur) due to an excess of injected fuel.	Engine coolant temperature sensor	If the value is -40°C (-40°F) or 140°C (284°F), the sensor circuit is open or shorted. After a long soak, the coolant temperature, intake air temperature, and ambient air temperature are approximately equal.
Coolant Temp	-

Battery Voltage
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Battery Voltage	When cranking, in cases when Battery Voltage becomes less than 5 V, the battery is depleted.	Battery	If 11 V or less, characteristics of some electrical components change.
Battery Voltage	Results of real-vehicle check: Ignition switch ON: 12.5 V Cranking (with engine warmed up): 9.0 V Idling (warm up the engine): 13.4 V Running without load (2500 rpm): 13.5 V Driving with the accelerator fully open at 2000 rpm: 13 V Driving with the accelerator fully open at 3000 rpm: 13.2 V

Starter Signal
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Starter Signal	Operation of ignition switch (STA) ON: Starter is operating OFF: Starter is not operating	Entry and Start system	Ignition switch (STA) output: ON: Starter is operating OFF: Starter is not operating
Starter Signal	-

Engine Speed of Cyl #1 (to #8)
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Engine Speed of Cyl #1 (to #8)	When cranking, the engine speed of each cylinder is the same under normal conditions. When a cylinder is approximately 100 rpm higher than the other cylinders, it is conceivable that the compression of that cylinder is being lost. Tech Tips This data is output only when the Active Test "Check the Cylinder Compression" is performed.	-	Output only when the Active Test "Check the Cylinder Compression" is performed. With this Active Test, the fuel injection is stopped. Indicates the speed of each cylinder when cranking. Example - Normal: "Engine speed" of all cylinders is approximately equal. No. 1 cylinder compression low: "Engine speed of Cyl#1" = approximately 300 rpm, "Engine speed of Cyl #2 to #8 cylinder" = approximately 200 rpm.
Engine Speed of Cyl #1 (to #8)	-

Immobiliser Communication
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Immobiliser Communication	Engine immobiliser system/Data List Click here	Engine immobiliser system/Problem Symptoms Table Click here	When there is a malfunction in the immobiliser system, a DTC is stored Click here
Immobiliser Communication	-

Diesel Injection

Target Common Rail Pressure
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Target Common Rail Pressure	-	-	Inspect the (actual) fuel pressure, comparing it against the common rail target value. Considered normal when the actual fuel pressure is within +/-5000 kPa of the target fuel pressure under stable conditions.
Target Common Rail Pressure	Results of real-vehicle check: Ignition switch ON: 32000 kPa Cranking: 29000 kPa Idling (warm up the engine): 32000 kPa (2 minutes after starting the vehicle) Running without load (2500 rpm): 62000 kPa Running without load (3500 rpm): 80200 kPa Driving with the accelerator fully open at 2000 rpm: 95000 kPa Driving with the accelerator fully open at 3000 rpm: 155000 kPa

Fuel Press
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Fuel Press	In a stable operating condition (e.g. idling), Fuel Press is Target Common Rail Pressure +/-5000 kPa. During cranking, if Fuel Press is lower than 25000 kPa, there may be difficulty starting. (Take care as there is a response lag when the pressure rises). When Fuel Press is lower than 25000 kPa, rough idling will occur.	If there is a fault with the fuel supply pump (lack of discharge quantity) or pressure limiter (will not fully close), the fuel pressure will drop. Also, a blocked fuel filter, leakage from fuel pipes, and lack of fuel will also make the fuel pressure drop. If air mixes with the fuel, the fuel pressure will shift away from the target fuel pressure. When there is a fault with the fuel supply pump, there is a possibility of lack of power, engine stall, rough idle and difficulty starting.	Fuel press is the actual common rail fuel pressure. Inspect by comparing Fuel Press with Target Common Rail Pressure. The ECM uses Fuel Press for feedback control of Target Fuel Pressure via the supply pump. The injection amount is determined based on the injection timing and fuel pressure. Also, the spray pattern is selected based on the fuel pressure.
Fuel Press	Results of real-vehicle check: Ignition switch ON: 0 kPa Cranking: 29000 kPa Idling (warm up the engine): 32000 kPa (2 minutes after starting the vehicle) Running without load (2500 rpm): 62000 kPa Driving with the accelerator fully open at 2000 rpm: 92000 kPa Driving with the accelerator fully open at 3000 rpm: 155000 kPa

Target Pump SCV Current
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Target Pump SCV Current	Idling after warming up, roughly 923 to 1123 mA. When this value is large, the pump is trying to increase the fuel discharge rate.	With this data, component fault not specified, use this data as a reference. If the current is 3000 mA or more, there is a possibility the suction control valve is stuck.	ECU-calculated value for the suction control valve actuation target current. Value is large when a high fuel pressure is desired. When this deviates from the standard value, it indicates that for some reason, even though the pump is running hard, the actual fuel pressure is inconsistent with the target fuel pressure.
Target Pump SCV Current	Results of real-vehicle check: Ignition switch ON: 0 mA Cranking: 1200 mA Running without load (2500 rpm): 1300 mA Driving with the accelerator fully open at 2000 rpm: 1440 mA Driving with the accelerator fully open at 3000 rpm: 1560 mA

Injection Feedback Val #1 (to #8)
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Injection Feedback Val #1 (to #8)	When idling after the engine is warmed up, the fuel quantity of each fuel injector is corrected to make each cylinder engine speed equal. Cylinders more than 3 mm³/st may have a fault. Tech Tips 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.	Fault with a fuel injector or lack of compression of a cylinder with a large Injection Feedback Val. Do a compression Active Test. If there is a cylinder that is around 100 rpm more than the other cylinder, there is a possibility that the compression of that cylinder is being lost. If all the cylinder speeds are even according to the compression Active Test result, then the fuel injector of the cylinder may have a fault. With fuel injector faults, other than difficulty starting, there is a possibility of rough idling, lack of power, black smoke, white smoke and knocking.	When idling after warm up, the injection amount for each cylinder is corrected to optimize the difference of each cylinder engine speed. Example: For cylinders that are slowing the engine speed compared to other cylinders, the injection volume is increased. "Injection Feedback Val" more than 3.0 mm³/st: Injector breakdown or insufficient compression is causing poor combustion.
Injection Feedback Val #1 (to #8)	-

Injection Volume
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Injection Volume	-	-	After warming up the engine, when Injection Volume during idling is 10 mm³/st or more, there is tendency for the injector to clog.
Injection Volume	Results of real-vehicle check: Cranking: 21 mm³/st (Note: Varies depending on coolant temperature) Idling (warm up the engine): 6 mm³/st Running without load (2500 rpm): 9 mm³/st Running without load (4700 rpm): 16 mm³/st Driving with the accelerator fully open at 2000 rpm: 50 mm³/st Driving with the accelerator fully open at 3000 rpm: 70 mm³/st

Diesel Throttle

Actual Throttle Position, Actual Throttle Position #2
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Actual Throttle Position Actual Throttle Position #2	When the ignition switch is turned to ON (engine stopped), the diesel throttle is fully open. When the ignition switch is turned from ON to off, the diesel throttle will be fully closed temporarily. With the diesel throttle stuck almost fully closed, there is a possibility of rough idling, engine stall, black smoke, difficulty starting and lack of power.	Diesel throttle body	Actual Throttle Position is the closing percentage of the throttle valve. Fully closed: 100% Fully open: 0% Tech Tips There is no connection with the accelerator. However, under full load, the throttle is usually fully open (0%).
Actual Throttle Position Actual Throttle Position #2	Results of real-vehicle check: Ignition switch ON: 0% Cranking: 0% Idling (warm up the engine): 84% Running without load (2500 rpm): 32% Driving with the accelerator fully open at 2000 rpm: 0% Driving with the accelerator fully open at 3000 rpm: 0%

Throttle Motor Duty #1, Throttle Motor Duty #2
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Throttle Motor Duty #1 Throttle Motor Duty #2	Normally operates at 50 +/-20%. If 50 +/-40% continues for a few seconds, it is conceivable that the throttle valve is not sliding properly. 0%: Drive throttle to open side 100%: Drive throttle to closed side	-	When this value is large but the actual opening angle does not move smoothly, there is an unable to close malfunction. If this value is small but the actual opening angle does not move smoothly, there is an unable to open malfunction. Usually this value is at approx. 50 +/-20%, but momentary jumps outside this range do occur. If a duty is outside 50 +/-40% for several seconds, it will be judged that the diesel throttle does not move properly and the MIL will be illuminated.
Throttle Motor Duty #1 Throttle Motor Duty #2	Results of real-vehicle check: Ignition switch ON: 61.5% Cranking: 63% Idling (warm up the engine): 37% Running without load (2500 rpm): 53% Driving with the accelerator fully open at 2000 rpm: 62.5% Driving with the accelerator fully open at 3000 rpm: 64%

Diesel EGR

Target EGR Valve Pos., Target EGR Valve Pos. #2
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Target EGR Valve Pos. Target EGR Valve Pos. #2	-	-	Fully open: 100% Fully closed: 0% Used for comparison to "Actual EGR Valve Pos".
Target EGR Valve Pos. Target EGR Valve Pos. #2	Results of real-vehicle check: Ignition switch ON: 0% Cranking: 0% Idling (warm up the engine): 43% Running without load (2500 rpm): 22% Driving with the accelerator fully open at 2000 rpm: 0% Driving with the accelerator fully open at 3000 rpm: 0%

Actual EGR Valve Pos., Actual EGR Valve Pos. #2
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
Actual EGR Valve Pos. Actual EGR Valve Pos. #2	Generally Actual EGR Valve Pos. = Target EGR Pos. (Fully closed = 0%, Fully open = 100%) The EGR valve Active Test can be used to check whether the Actual EGR Valve Pos. = Target EGR Pos.	EGR valve assembly	Inspect while comparing to "Target EGR Valve Pos.". Sometimes the malfunction only occurs around a certain temperature, so refer to the engine coolant temperature and outside temperature at the time the malfunction occurred.
Actual EGR Valve Pos. Actual EGR Valve Pos. #2	Results of real-vehicle check: Ignition switch ON: 0% Cranking: 0% Idling (warm up the engine): 84% Running without load (2500 rpm): 34% Driving with the accelerator fully open at 2000 rpm: 0% Driving with the accelerator fully open at 3000 rpm: 0%

EGR Close Lrn. Status
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
EGR Close Lrn. Status	"OK" means the fully closed position learning has completed normally. When NG, the learned fully closed position may be outside of the normal range.	-	After disconnecting and reconnecting the battery cable, if the ignition switch has not been turned off once, learning may not be completed.
EGR Close Lrn. Status	-

EGR Close Lrn. Val.
Data List	Judgment of Data List Values	Faulty Component	Diagnosis Note
EGR Close Lrn. Val.	Leave the vehicle idling, with the EGR Close Lrn. Status OK, the normal range of EGR Close Lrn. Val. is within 3.5 to 4.5 V. In cases when EGR Close Lrn. Status is NG or EGR Close Lrn. Val. is at the maximum or minimum (3.5 to 4.5 V) of normal range, it is possible that the EGR valve is not completely closed or a foreign object is lodged in the EGR valve seat area.	-	This value is the EGR position sensor output voltage. As the maximum and minimum settings are 3.5 V and 4.5 V, if the value becomes stuck at either of these, there is a malfunction in the lift sensor or the valve position is shifted (due to foreign matter, etc.).
EGR Close Lrn. Val.	-

Actual Examples of Malfunction
Tech Tips
- The purpose of the following examples is 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 from the Land Cruiser 1VD-FTV
1. Fuel is not being supplied to supply pump (Low pressure fuel line clogged)
2. Fuel is not being injected (Injectors are leaking)
3. Fuel is not being injected (EDU circuit malfunction)
4. Fuel supply pump malfunction (Suction control valve momentary sticking)
5. Increased opening delay of injectors (Internal contamination)

INSPECTION PROCEDURE

Explanation of Symptom

Starting Trouble

For good starting it is essential to have:

Sufficient cranking speed.
Properly operating engine preheating system.
Good quality fuel.

The fuel is ignited by the heat which is generated with compression pressure.

With problems such as a depleted battery, the crankshaft speed can become low, or if the engine compression is leaking, the compression pressure will not rise and there will be difficulty starting.

When the engine is cold, even if there is compression heat, it will escape from the combustion chamber. For this reason, when the engine is started when it is cold, the glow plugs heat the compressed air.

Also after starting the engine, by charging the glow plugs for a fixed time set according to the engine coolant temperature, diesel knocking and white smoke are prevented. The quantity of fuel injected is determined by the fuel pressure and also the amount of time the fuel injector is open.

Trouble Area Chart According to Problem Cause
Note
- After replacing the ECM, the new ECM needs registration Click here and initialization Click here.
- After replacing the fuel supply pump, the ECM needs initialization Click here.
- After replacing the fuel injector, the ECM needs registration Click here.
Tech Tips
- 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 assume the vehicle is normal when the Data List outputs standard values. There may be concealed factors of the malfunction.

PROCEDURE

CHECK ENGINE CRANKING CONDITION

Check the engine cranking condition.

Result
Result	Proceed to
Does not crank at all.	A
Low cranking speed. Tech Tips When cranking speed is low, especially when the temperature is low, check if the engine oil grade matches the recommendation.	B
Cranking is OK.	C

CHECK BATTERY CONDITION Click here

CHECK INITIALIZATION (FUEL SUPPLY PUMP) Click here

CHECK BATTERY CONDITION
1. Check battery condition Click here.
NG
REPLACE BATTERY

OK
CHECK COMMUNICATION BETWEEN INTELLIGENT TESTER AND ECM
1. Connect the intelligent tester to the DLC3.
2. Turn the ignition switch to ON and turn the tester on.
3. Check if the normal starting screen appears (check whether communication with the ECM is possible).
  
  Tech Tips
  
  Use a tester that is able to communicate with other vehicles.
  
  OK
  
  Communication is possible (Vehicle can be recognized).
NG
GO TO ECM POWER SOURCE CIRCUIT Click here

OK

OK
Communication is possible (Vehicle can be recognized).

READ VALUE USING INTELLIGENT TESTER (CLUTCH SWITCH)

Tech Tips

This inspection is not necessary for A/T vehicles.

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the tester on.
Enter the following menus: Powertrain / Engine / Data List / All Data / Clutch Switch.

Read the value displayed on the tester.

Standard Value

Tester Display	Condition	Specified Condition
Clutch Switch	Clutch pedal depressed	ON

Result

Result	Proceed to
OK	A
NG (for LHD)	B
NG (for RHD)	C

REPLACE CLUTCH START SWITCH (for LHD) Click here

REPLACE CLUTCH START SWITCH (for RHD) Click here

READ ALL OUTPUT DTCS

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the tester on.

Enter the following menus: Utility / All Codes.

Result
Result	Proceed to
No DTC is output	A
DTCs related to engine are output	B

GO TO RELATED DTC

INSPECT SMART START SYSTEM (IN CASE OF VEHICLES EQUIPPED WITH SMART ENTRY AND START SYSTEM)

Check if the "Door Control Transmitter" functions of each key functions properly.
Tech Tips
- Check if the engine starts properly with another key.
- If the doors can not be opened/closed by using the "Door Control Transmitter" function of the key, the battery inside the key may be depleted. In such a case the engine can not be started by pushing the ENGINE START/STOP button.
- When the door control transmitter battery is depleted, the engine can only be started by holding the door control transmitter against the ENGINE START/STOP button.
- If the inspection result is that the problem only occurs in certain locations or times of day, the possibility of wave interference is high. Also, added vehicle components may cause wave interference. If any component installed, remove them and perform the operation check.
  
  Near broadcasting stations, large screens, airports, transformer stations, gasoline stations, etc., the door control transmitter may not operate due to electric wave interference.
NEXT
INSPECT CRANKING HOLDING FUNCTION CIRCUIT

Tech Tips

Check that "Starter Signal" in the Data List changes to ON when the engine is started.
1. Inspect the cranking holding function circuit Click here.
NEXT

END
CHECK INITIALIZATION (FUEL SUPPLY PUMP)

When the engine does not start or another problem such as rough idling is present, perform initialization and check to see if the problem symptoms disappear. If the problem symptoms do not disappear, perform the next procedure.

Tech Tips

When replacing the ECM, the supply pump initialization must be performed Click here.

NEXT

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 / DTC.

Read the DTCs.

Result
Result	Proceed to
No DTC is output	A
DTCs related to engine are output	B

REPAIR OR REPLACE ENGINE CONTROL SYSTEM ACCORDING TO DTC OUTPUT Click here

TAKE DATA LIST DURING STARTING AND IDLING

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the tester on.
Enter the following menus: Powertrain / Engine / Data List / All Data.

Take a snapshot of the following Data Lists with the intelligent tester during "Ignition switch ON (5 seconds) → Starting → Idling (10 seconds)".

Tech Tips

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.
When there is trouble starting with a cold engine, take the snapshot when the engine is cold. Then warm up the engine (engine coolant temperature 70°C (158°F) or more) and after idling the vehicle for 1 minute (A/C off, electrical load off), take a snapshot of the data for 15 seconds while idling.
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.

Data List
Starter Signal
Engine Speed
Fuel Press
Target Common Rail Pressure
Target Pump SCV Current
Injection Volume
Main Injection Period
Inj. FB Vol. for Idle
Injection Feedback Val #1
Injection Feedback Val #2
Injection Feedback Val #3
Injection Feedback Val #4
Injection Feedback Val #5
Injection Feedback Val #6
Injection Feedback Val #7
Injection Feedback Val #8
Battery Voltage
Actual EGR Valve Pos. Actual EGR Valve Pos. #2
Target EGR Pos Target EGR Pos. #2
Actual Throttle Position Actual Throttle Position #2
MAF
Target Booster Pressure
MAP

Reference Values during Engine Start (Point A)
Data List	Value	Unit
Starter Signal	ON	-
Engine Speed	524	rpm
Fuel Press	27820	kPa
Target Common Rail Pressure	25000	kPa
Injection Volume	22.71	μs
Main Injection Period	1142	μs
Inj. FB Vol. for Idle	-1.33	mm³/st
Battery Voltage	11.0	V
Target EGR Pos. Target EGR Pos. #2	0	%
Actual EGR Valve Pos. Actual EGR Valve Pos. #2	0.0	%
Actual Throttle Position Actual Throttle Position #2	-1	%
MAF	16.45	g/sec
MAP	99	kPa
Target Boost Pressure	100.91	kPa
Coolant Temp	40	°C

Data Condition at Idling (Engine Warmed Up)
Data List	Value	Unit
Engine Speed	599	rpm
Target Booster Pressure	99.23	kPa
MAP	97	kPa
MAF	8.39	g/sec
Target Common Rail Pressure	32000	kPa
Fuel Press	32100	kPa
Injection Volume	6.13	mm³/st
Actual EGR Valve Pos. Actual EGR Valve Pos. #2	43.5	%
Actual Throttle Position Actual Throttle Position #2	84	%
Injection Feedback Val #1	0.0	mm³/st
Injection Feedback Val #2	0.3	mm³/st
Injection Feedback Val #3	0.0	mm³/st
Injection Feedback Val #4	-0.4	mm³/st
Injection Feedback Val #5	-0.4	mm³/st
Injection Feedback Val #6	0.3	mm³/st
Injection Feedback Val #7	0.0	mm³/st
Injection Feedback Val #8	-0.5	mm³/st
Target EGR Pos. Target EGR Pos. #2	43.5	%
Coolant Temp	78	°C

Tech Tips

Actual Examples of Malfunction (See "Diagnostic Help" menu)

Starting is not possible

Fuel is not supplied to supply pump.

Fuel Press: Approximately 1000 kPa or less during cranking.
Fuel is not being injected due to EDU circuit malfunction.

Fuel Press: 80000 to 90000 kPa during cranking.
Air in injectors.

Fuel Press: 60000 to 70000 kPa during cranking.

Cranking time is long

Suction control valve is stuck.

Target Pump SCV Current intermittently reaches 3000 mA or more. The suction control valve plunger intermittently becomes stuck. If there is difficult to start when the engine is cold, cool the engine and inspect it.

Injector clogging or internal contamination:
Injector clogging or internal contamination:

Injection Feedback Val # of one or more of the cylinders is 3 mm³/st or more.

Injection Feedback Val # can be read when the engine is idling after being warmed up.

CHECK SNAPSHOT (FUEL PRESS, TARGET COMMON RAIL PRESSURE ETC.)

Check Fuel Press and Target Common Rail Pressure in the snapshot taken when the engine was starting.

Result
Result	Proceed to
2 seconds after Starter Signal turns from OFF to ON, Fuel Press is less than "Target Common Rail Pressure -5000 kPa" Tech Tips As long as the fuel pressure remains below 5000 kPa, the ECM stops sending the injection open signal (IJT) to the EDU, and then the actual injection duration remains 0 microseconds.	A
2 seconds after Starter Signal turns from OFF to ON, Fuel Press is 5000 kPa or more higher than Target Common Rail Pressure	B
2 seconds after Starter Signal turns from OFF to ON, Fuel Press is within +/-5000 kPa of Target Common Rail Pressure	C

Tech Tips

Fuel pressure is about 20000 to 35000 kPa when engine cranking and engine coolant temperature 0°C (32°F) or more.

Fuel pressure increases rapidly during cranking.

CHECK SNAPSHOT Click here

CHECK SNAPSHOT (TARGET PUMP SCV CURRENT) Click here

BLEED AIR FROM FUEL SYSTEM
1. Using the hand pump as indicated by the arrow in the illustration, bleed air from the fuel system. Continue pumping until pumping becomes difficult.
  
  Tech Tips
  
  When the fuel pressure during cranking is extremely low (1000 kPa or less), it is possible that fuel is not being supplied to the supply pump.
NEXT
CHECK IF FUEL IS BEING SUPPLIED TO FUEL SUPPLY PUMP
1. Disconnect the inlet hose from the fuel supply pump.
2. 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.
  Tech Tips
  - When lack on fuel, fuel pressure drops.
  - Inspect for fuel filter clogging.
    
    (Check that the fuel filter is not clogged)
NG
CHECK AND REPLACE CLOGGED FUEL PIPE (INCLUDING FUEL FREEZING) (FUEL TANK - FUEL SUPPLY PUMP)

OK
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
1. Check whether the difficulty starting has been successfully repaired by starting the engine.
  
  Tech Tips
  
  Fuel pressure during cranking is within +/-5000 kPa of target fuel pressure.
  
  OK
  
  Malfunction has been repaired successfully.
NG
CHECK FUEL LEAK (FUEL SUPPLY PUMP) Click here

OK

END

CHECK FUEL LEAK (FUEL SUPPLY PUMP)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the tester ON.
Enter the following menus: Powertrain / Engine / Data List / Fuel Press.

Pinch the supply pump return hose and check that Fuel Press during cranking increases.

Result
Result	Proceed to
Fuel Press increases	A
No change	B

REPLACE FUEL SUPPLY PUMP Click here

CHECK FUEL LEAK (PRESSURE LIMITER (COMMON RAIL (for Bank 2))

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the tester ON.
Enter the following menus: Powertrain / Engine / Data List / Fuel Press.

Pinch the pressure limiter return hose and check that Fuel Press during cranking increases.

Result
Result	Proceed to
Fuel Press increases	A
No change	B

REPLACE COMMON RAIL (for Bank 2) Click here

REPLACE FUEL SUPPLY PUMP
1. Replace fuel supply pump Click here.
NEXT
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
1. Check whether the difficulty starting has been successfully repaired by starting the engine.
  
  Tech Tips
  
  Fuel pressure during cranking is within +/-5000 kPa of target fuel pressure.
NEXT

END

CHECK SNAPSHOT (TARGET PUMP SCV CURRENT)

Check Target Pump SCV Current in the snapshot taken when the engine was starting.

Result

Result	Proceed to
Target Pump SCV Current is 3000 mA or more	A
Target Pump SCV Current is less than 3000 mA	B

REPLACE FUEL SUPPLY PUMP Click here

CHECK DATA LIST

Check Injection Feedback Val # and Injection Volume in the snapshot taken when the engine was idling.

Result

Result	Proceed to
Injection Feedback Val #1 to #8 is outside the range of +/-3 mm³/st Tech Tips There may be malfunction in the corresponding cylinder.	A
Injection Feedback Val #1 to #8 is within the range of +/-3 mm³/st and Injection Volume is more than 10 mm³/st	B*
Injection Feedback Val #1 to #8 is within the range +/-3 mm³/st and Injection Volume is 10 mm³/st or less	C

Tech Tips

*: When case "B" occurs usually symptoms may be noticeable, such as difficult starting, rough idling, knocking or black smoke at high common rail pressure.

REPLACE FUEL INJECTORS OF ALL CYLINDERS Click here

CHECK TEMPERATURE WHEN STARTING TROUBLE OCCURS Click here

PERFORM ACTIVE TEST USING INTELLIGENT TESTER

Tech Tips

Use this Active Test to determine the malfunctioning cylinder.
1. Connect the intelligent tester to the DLC3.
2. Start the engine and turn the tester on.
3. Enter the following menus: Powertrain / Engine / Active Test / Control the Cylinder #1 to #8 Fuel Cut.
  Tech Tips
  - 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.
NEXT
PERFORM ACTIVE TEST USING INTELLIGENT TESTER

Tech Tips

Use this Active Test to help determine whether a cylinder has compression loss or not.
1. Connect the intelligent tester to the DLC3.
2. Turn the ignition switch to ON and turn the tester on.
3. Enter the following menus: Powertrain / Engine / Active Test / Check the Cylinder Compression / Data List / Compression / Engine Speed of Cyl #1 to #8.
4. Check the engine speed during the Active Test.
  
  OK
  
  If the values of Engine Speed Cyl #1 to #8 are within +/-10 rpm of each other.
  
  Tech Tips
  
  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.
OK
REPLACE FUEL INJECTOR OF MALFUNCTIONING CYLINDER Click here

NG
CHECK CYLINDER COMPRESSION PRESSURE OF MALFUNCTIONING CYLINDER Click here
CHECK CYLINDER COMPRESSION PRESSURE OF MALFUNCTIONING CYLINDER

Tech Tips

Measure the compression of the cylinder that had a high speed during the Active Test "Check the Cylinder Compression".
1. Check the cylinder compression pressure Click here.
NG
CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK
REPLACE FUEL INJECTOR OF MALFUNCTIONING CYLINDER

Tech Tips

The injector is determined to be faulty as the corresponding cylinder is malfunctioning, but has no compression loss.

NEXT

END

CHECK TEMPERATURE WHEN STARTING TROUBLE OCCURS

Check the temperature when starting trouble occurs.

Result
Result	Proceed to
Difficult to start only for cold engine.	A
Difficult to start both for cold and warmed up engine.	B

CHECK FUEL QUALITY Click here

INSPECT ENGINE COOLANT TEMPERATURE SENSOR
1. Inspect the engine coolant temperature sensor Click here.
NG
REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

OK

INSPECT GLOW PLUG ASSEMBLY (RESISTANCE)

Disconnect the glow plug connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
Glow plug terminal - Body ground	20°C (68°F)	Approximately 1 Ω

Tech Tips

If any of the glow plugs has an open circuit, the engine power will be insufficient only when the engine is cold.

Note

Exercise extreme care not to damage the glow plug pipes. Damaging them could cause an open circuit or shorten the life of the glow plugs.
Keep the glow plugs free of oil and fuel while cleaning.
Wipe any oil off of the terminal and Bakelite washer with a clean, dry cloth during inspection.
Do not apply more than 11 V to the glow plugs as it may cause an open circuit.

REPLACE GLOW PLUG ASSEMBLY Click here

INSPECT INJECTOR COMPENSATION CODE
1. Read the injector compensation code Click here.
  
  OK
  
  Compensation codes stored in the ECM match compensation codes of the installed fuel injectors.
NG
PERFORM REGISTRATION FUEL INJECTOR COMPENSATION CODE Click here

OK
CHECK FUEL QUALITY
1. Check that fuel with cetane number is used.
NEXT
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
1. Check whether the difficulty starting has been successfully repaired by starting the engine.
NEXT

END
CHECK SNAPSHOT

Tech Tips

When all Data List values are OK and Fuel Press is higher than Target Common Rail Pressure, perform the following inspection.

NEXT

INSPECT INJECTOR DRIVER (EDU POWER SOURCE)

Disconnect the C73 and C74 No. 1 injector driver (EDU) connectors.
Disconnect the C75 and C76 No. 2 injector driver (EDU) connectors.

Measure the voltage according to the value(s) in the table below.

Standard Voltage

No. 1
Tester Connection	Switch Condition	Specified Condition
C74-8 (+B) - C73-1 (GND)	Ignition switch ON	11 to 14 V

Standard Voltage

No. 2
Tester Connection	Switch Condition	Specified Condition
C76-8 (+B) - C75-1 (GND)	Ignition switch ON	11 to 14 V

GO TO INJECTOR CIRCUIT Click here

INSPECT FUEL INJECTOR

Tech Tips

If there is no initial combustion during cranking, there may be air in the injectors.

NEXT

END