Inspection Procedure 7: Improper Idling


PROBABLE CAUSES



  • Improper fuel used
  • Fuel contaminated with foreign matter
  • Injector leaking or clogged
  • Failed injector
  • Fuel injection learning failure
  • Fuel filter clogged
  • Fuel line leaking or clogged
  • Failed fuel pressure limiter valve
  • Failed rail pressure sensor
  • Failed supply pump (suction control valve)
  • Failed supply pump correction learning
  • Failed EGR system operation
  • Failed valve clearance adjustment
  • Failed engine-ECU
  • Compression pressure low

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code.

Q. Is the diagnosis code set?
Inspection chart for diagnosis code (Refer to ).
Go to Step 2.

STEP 2. Check injector identification code.

  • Check injector identification code (Refer to GROUP 00 - Precautions Before Service - Injector Identification code Registration Procedure ).

Q. Is the check result normal?
Go to Step 3.
Register the injector ID.

STEP 3. M.U.T.-III data list.

  • Refer to Data List Reference Table .

  1. Item 16: EGR valve position sensor
  2. Item 17: EGR valve target position

Q. Are the check results normal?
Go to Step 4.
Perform the diagnosis code classified check procedure for the sensor that has shown an abnormal data value (Refer to Inspection Chart for Diagnosis Code ).

STEP 4. Confirm the using fuel.

Q. Is the specified fuel being used?
Go to Step 5.
Replace fuel.

STEP 5. Check fuel supply line.

  • Check for fuel leakage and clogging.
  • Check fuel filter for clogging.

Q. Is the check result normal?
Go to Step 6.
Repair or replace the failed item.

STEP 6. Priming (air bleeding)

  • Bleed air.

Q. Does trouble symptom persist?
Go to Step 7.
The procedure is complete.

STEP 7. M.U.T.-III actuator test.

  • Refer to Actuator Test Reference Table .

  1. Item 19: Suction control valve

Q. Is the check result normal?
Go to Step 8.
Replace the suction control valve. After replacing the suction control valve, learn the supply pump (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

STEP 8. Check suction control valve itself.

  • Check suction control value itself (Refer to ).

Q. Is the check result normal?
Go to Step 9.
Replace the suction control valve. After replacing the suction control valve, learn the supply pump (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

STEP 9. M.U.T.-III data list.

  • Refer to Data List Reference Table .

  1. Item 63: Rail pressure sensor
  2. Item 64: Rail pressure target

Q. Are the check results normal?
Go to Step 11.
Go to Step 10.

STEP 10. Replace the rail pressure sensor.

  • Replace the common-rail assembly.

Q. Does trouble symptom persist?
Go to Step 17.
The procedure is complete.

STEP 11. Check the waveforms of crank angle sensor and camshaft position sensor.

  • Check the output waveforms on an oscilloscope (Refer to ).

Q. Is the check result normal?
Go to Step 12.
Proceed to the inspection procedure by diagnosis code for the abnormal waveform (Refer to Inspection Chart for Diagnosis Code ).

STEP 12. Check compression pressure.

  • Check compression pressure (Refer to GROUP 11A On-vehicle Service - Compression Pressure Check ).

Q. Is the check result normal?
Go to Step 13.
Check and repair the engine itself.

STEP 13. Check valve clearance.

  • Check valve clearance (Refer to GROUP 11A - On-vehicle Service - Valve Clearance Check and Adjustment ).

Q. Is the check result normal?
Go to Step 14.
Adjust the valve clearance.

STEP 14. M.U.T.-III actuator test.

  • Refer to Data List Reference Table .

  1. Item 15: Injector No. 1
  2. Item 16: Injector No. 2
  3. Item 17: Injector No. 3
  4. Item 18: Injector No. 4

Q. Are the check results normal?
Go to Step 15.
Replace the injector at the failed cylinder. After replacing the Injector, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

STEP 15. Check injector itself.

  • Check injector itself (Refer to ).

Q. Is the check result normal?
Go to Step 16.
Replace the injector at the failed cylinder. After replacing the Injector, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

STEP 16. M.U.T.-III data list.

  • Refer to Data List Reference Table .

  1. Item 5: Barometric pressure sensor
  2. Item 6: Manifold absolute pressure sensor
  3. Item 7: Engine coolant temperature sensor
  4. Item 8: EGR gas temperature sensor <Euro5b>
  5. Item 8: Intake air temperature sensor No. 2 <Except Euro5b>
  6. Item 9: Accelerator pedal position sensor
  7. Item 21: Fuel temperature sensor
  8. Item 43: Intake air temperature sensor No. 1
  9. Item 45: Throttle position sensor

Q. Are the check results normal?
Go to Step 17.
Perform the diagnosis code classified check procedure for the sensor that has shown an abnormal data value (Refer to Inspection Chart for Diagnosis Code ).

STEP 17. Check the trouble symptoms.

Q. Does trouble symptom persist?
Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ). After registering the injector identification code, the vehicle equipped with the DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Emission Control - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).