ECD SYSTEM > Engine Knocking or Rattling |
| Malfunction Condition | Main Trouble Area | Related Trouble Area |
| Combustion in diesel engines takes place by means of self-ignition. If the timing of the ignition is delayed, the pressure inside the combustion chamber will increase too fast, which leads to uncontrolled combustion and can be heard as diesel knocking. If any of the following conditions are met, engine knocking may occur due to the fact that
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| 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 | |
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| 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 | |
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
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| Diagnostic Trouble Code | Even if Fuel Press is less than Target Common Rail Pressure, a DTC may 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
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| Diagnostic Trouble Code | Even if Fuel Press is less than Target Common Rail Pressure, a DTC may not be stored. | |
| Component | Fuel injector | |
| Main fault | Injection hole blockage Nozzle needle or valve piston does not move smoothly | |
| Symptoms | Rough idle, lack of power, black smoke, white smoke, knocking | |
| Data List | Injection Feedback Val
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| 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
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| Diagnostic Trouble 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 Pos.
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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 Engine Knocking and Rattling |
Engine Control
| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
| Engine Speed | Idling: 720 to 820 rpm |
| 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 |
| When MAP is low, the following conditions are possible:
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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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| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
| Intake Air | - | Intake air temperature sensor. |
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| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
| Coolant Temp |
| Engine coolant temperature sensor |
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| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
| Engine Speed of Cyl #1 (to #4) | 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.
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Diesel Injection
| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
| Target Common Rail Pressure | - | - |
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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 | 1530 mA or less |
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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) |
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| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
| Injection Volume | - | - | If injectors are clogged, fuel quality is poor, the fuel filter is clogged, or engine friction increases, then "Injection Volume" will increase. |
Results of real-vehicle check:
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| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
| Pilot 1 Injection Period | Idling: 140 to 340 μs | - | - |
Results of real-vehicle check:
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| Data List | Judgment of Data List Values | Faulty Component | Diagnosis Note |
| Main Injection Period | Idling: 232 to 432 μs | - | - |
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 |
| Diesel throttle body | 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. |
| EGR valve assembly |
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Results of real-vehicle check:
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| Explanation of Symptom |
| Engine knocking or rattling | Combustion in diesel engines takes place by means of self-ignition. If the timing of the ignition is delayed, the pressure inside the combustion chamber will increase too fast, which leads to uncontrolled combustion and can be heard as diesel knocking. If one of the following conditions are met, engine knocking may occur due to the fact that
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| 1.CHECK FOR KNOCKING SOUND |
Open the hood and check for knocking.
| Result | Proceed to |
| Knocking | A |
| No knocking | B |
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| A | |
| 2.CHECK HARNESS AND CONNECTOR (IN ENGINE ROOM) |
Check the harness and connector connections of common rail system components.
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| OK | |
| 3.CHECK INTAKE SYSTEM (PROCEDURE 3) |
Check the intake system (turbocharger, MAP sensor, EGR valve, etc.).
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| OK | |
| 4.READ OUTPUT DTCS (RELATING 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 DTCs.
| Result | Proceed to |
| No output | A |
| Engine related DTCs | B |
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| A | |
| 5.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 (do not start the engine).
| Result | Proceed to |
| MAP and Atmosphere Pressure have the same value | A |
| MAP is different from actual atmospheric pressure | B |
| Atmosphere Pressure is different from actual atmospheric pressure | C |
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| A | |
| 6.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.
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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 tester during the Active Test.
Maintain the engine speed of 3500 rpm, and then press the "Start" button.
Measure the difference between the target fuel pressure (Target Common Rail Pressure) and the actual fuel pressure (Fuel Press) when the Active Test / Test the Fuel Leak is performed.

Read the value of Target Pump SCV Current in the Data List when the "Test the Fuel Leak" Active Test is performed.
| Result | Proceed to |
| Both results are within standard | A |
| Fuel pressure exceeds "Target Common Rail Pressure + 15000 kPa" and/or Target Pump SCV Current value is out of standard range | B |
| Fuel pressure does not reach "Target Common Rail Pressure - 15000 kPa" | C |
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| A | |
| 7.CHECK INJECTOR COMPENSATION CODE |
Check the injector compensation codes (Click here).
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| OK | |
| 8.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED |
Check whether the malfunction has been successfully repaired.
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| OK | ||
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| 9.READ VALUE USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION) |
Turn the ignition switch to ON.
Turn the ignition switch off and wait for 30 seconds or more.
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 / Control the EGR Step Position / Data List / Actual EGR Valve Pos.
When changing the Active Test value from 0 to 100%, check that Actual EGR Valve Pos. smoothly changes to the set opening angle.
| EGR Valve Condition | Actual EGR Valve Pos. |
| Fully closed | 0% |
| Fully open | About 100% |
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| OK | |
| 10.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (DIESEL THROTTLE TARGET ANGLE) |
Connect the intelligent tester to the DLC3.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Diesel Throttle Target Angle.
When continuously changing the Active Test value to 0, 30, 60, 90, 60, 30 and 0%, check that Actual Throttle Position smoothly changes to the set opening angle.
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| OK | |
| 11.CHECK THE TEMPERATURE WHEN KNOCKING OCCURS |
Check the temperature when knocking trouble occurs.
| Result | Proceed to |
| Knocking only for cold engine | A |
| Knocking both for cold and warmed up engine | B |
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| A | |
| 12.INSPECT ENGINE COOLANT TEMPERATURE SENSOR |
After warming up the engine, the engine coolant temperature should be 60°C (140°F) or more. After leaving the vehicle overnight, the engine coolant temperature should be nearly equal to the intake air temperature.
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| OK | |
| 13.CHECK PRE-HEATING CONTROL CIRCUIT |
Check the pre-heating control circuit (Click here).
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| OK | |
| 14.READ VALUE USING INTELLIGENT TESTER (INJECTOR FEEDBACK VAL #1 TO #4) |
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 / Injector Feedback Val. #1 to #4.
Start the engine.
Read the values during engine idling when the engine is cold, and write them down.
| Tester Display | Condition | Specified Condition |
| Injector Feedback Val. #1 Injector Feedback Val. #2 Injector Feedback Val. #3 Injector Feedback Val. #4 | Idling with cold engine | Between -2.0 and 2.0 mm3/st |
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| OK | |
| 15.READ VALUE USING INTELLIGENT TESTER (MAP AND MAF) |
Connect the intelligent tester to the DLC3.
Start the engine, warm it up, and then turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / MAP and MAF.
| Item | Engine Speed*1 | Standard Range | Description |
| MAP*2 | Ignition switch ON (engine stopped) | Same as atmospheric pressure | Intake manifold internal pressure detected by manifold absolute pressure sensor |
| Idling | 90 to 102 kPa (675 to 765 mmHg, 26.58 to 30.12 in.Hg) | ||
| 3000 rpm (no engine load) | 100 to 150 kPa (750 to 1125 mmHg, 29.53 to 44.29 in.Hg) | ||
| 3500 rpm (driving with full throttle acceleration) | Min. 180 kPa (1350 mmHg, 53.15 in.Hg) | ||
| MAF*2, *3 | Ignition switch ON (engine stopped) | Less than 0.5 gm/sec | Intake air volume detected by mass air flow meter |
| Idling | 3.5 to 12 gm/sec | ||
| 2000 rpm (no engine load) | 10 to 40 gm/sec | ||
| 3500 rpm (driving with full throttle acceleration) | Min. 67 gm/sec |
| Item | Result | Proceed to |
| MAP and MAF | Within standard range | A |
| MAP and MAF | Outside standard range | B |
| Only MAP | Outside standard range | C |
| Only MAF | Outside standard range | D |
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| A | |
| 16.INSPECT ELECTRIC EGR VALVE ASSEMBLY |
Remove the electric EGR valve assembly (Click here).
Visually check the electric EGR control valve for deposits. If there are deposits, clean the electric EGR control valve.
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 clearance between the valve and body.

Reinstall the electric EGR valve assembly (Click here).
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| OK | |
| 17.BASIC INSPECTION |
Check the fuel quality.
Check the fuel line for air.
Check the fuel system for blockages.
Check the air filter.
Check the engine oil.
Check the engine idling speed and maximum engine speed.
Check the vacuum pump.
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| OK | |
| 18.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED |
Check whether the malfunction has been successfully repaired.
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| OK | ||
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| 19.READ VALUE USING INTELLIGENT TESTER (INJECTION VOLUME AND INJECTOR) |
Connect the intelligent tester to the DLC3.
Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.
Allow the engine to idle for 1 minute or more.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Injection Volume and Injector Feedback Val. #1 to #4.
Read the values during engine idling.
| Tester Display | Condition | Specified Condition |
| Injection Volume | Idling | 8 mm3/st or less |
| Injector Feedback Val. #1 Injector Feedback Val. #2 Injector Feedback Val. #3 Injector Feedback Val. #4 | Idling | Between -2.0 and 2.0 mm3/st |
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| OK | ||
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| 20.BLEED AIR FROM FUEL SYSTEM |
Bleed the air from the fuel system (Click here).
| NEXT | |
| 21.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.
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Enter the following menus: Powertrain / Engine and ECT/ Active Test / Test the Fuel Leak / Data List / Fuel Press and Target Common Rail Pressure.
Take a snapshot with the tester during the Active Test.
Maintain the engine speed of 3500 rpm, and then press the "Start" button.
Measure the difference between the target fuel pressure (Target Common Rail Pressure) and the actual fuel pressure (Fuel Press) when the Active Test / Test the Fuel Leak is performed.

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| OK | |
| 22.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED |
| NEXT | ||
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| 23.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.
| Tester Connection | Condition | Specified Condition |
| B42-2 - B9-12 (PCV) | Always | Below 1 Ω |
| Tester Connection | Condition | Specified Condition |
| B42-2 or B9-12 (PCV) - Body ground | Always | 10 kΩ or higher |
Reconnect the suction control valve connector.
Reconnect the ECM connector.
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| OK | |
| 24.CONFIRM IF FUEL BEING SUPPLIED TO FUEL SUPPLY PUMP |
Disconnect the inlet hose from the fuel supply pump.
Operate the hand pump and check that fuel is being supplied to the fuel supply pump.
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| OK | |
| 25.REPLACE FUEL SUPPLY PUMP |
Replace the fuel supply pump (Click here).
| NEXT | |
| 26.BLEED AIR FROM FUEL SYSTEM |
Bleed the air from the fuel system (Click here).
| NEXT | |
| 27.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.
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Enter the following menus: Powertrain / Engine and ECT/ Active Test / Test the Fuel Leak / Data List / Fuel Press and Target Common Rail Pressure.
Take a snapshot with the tester during the Active Test.
Maintain the engine speed of 3500 rpm, and then press the "Start" button.
Measure the difference between the target fuel pressure (Target Common Rail Pressure) and the actual fuel pressure (Fuel Press) when the Active Test / Test the Fuel Leak is performed.

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| 28.REPLACE COMMON RAIL ASSEMBLY |
Replace the common rail assembly (Click here).
| NEXT | |
| 29.BLEED AIR FROM FUEL SYSTEM |
Bleed the air from the fuel system (Click here).
| NEXT | |
| 30.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED |
| NEXT | ||
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| 31.REPLACE INJECTOR ASSEMBLY |
Replace the injector assembly (Click here).
| NEXT | |
| 32.PERFORM REGISTRATION AND INITIALIZATION |
Register the injector compensation codes (Click here).
Perform Pilot Quantity Learning Values Reset (Click here).
| NEXT | |
| 33.BLEED AIR FROM FUEL SYSTEM |
Bleed the air from the fuel system (Click here).
| NEXT | |
| 34.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED |
| NEXT | ||
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| 35.PERFORM REGISTRATION AND INITIALIZATION |
Register the injector compensation codes (Click here).
Perform Pilot Quantity Learning Values Reset (Click here).
| NEXT | |
| 36.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED |
| NEXT | ||
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