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 fuel pressure sensor
- Failed supply pump (suction control valve)
- Failed supply pump correction learning
- Failed EGR system operation
- Open/short circuit or harness damage in alternator FR terminal circuit
- Failed alternator
- Failed valve clearance adjustment
- Failed engine-ECU
- Compression pressure low
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STEP 1. M.U.T.-III diagnosis code.
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Q.
Is the diagnosis code set?
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Inspection chart for diagnosis code (Refer to ).
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Go to Step 2.
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STEP 2. M.U.T.-III data list.
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- Refer to Data List Reference Table
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- Item 5: Barometric pressure sensor
- Item 6: Manifold absolute pressure sensor
- Item 7: Engine coolant temperature sensor
- Item 8: EGR gas temperature sensor
- Item 9: Accelerator pedal position sensor (main)
- Item 10: Accelerator pedal position sensor (sub)
- Item 21: Fuel temperature sensor
- Item 43: Intake air temperature sensor
- Item 45: Throttle position sensor
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Q.
Are the check results normal?
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Go to Step 3.
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Perform the diagnosis code classified check procedure for the sensor that has shown an abnormal data value (Refer to Inspection Chart for Diagnosis Code ).
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STEP 3. Check injector identification code.
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- Check injector identification code (Refer to GROUP 00 - Precautions before Service - Injector Identification Code Registration Procedure <4N1>
).
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Q.
Is the check result normal?
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Go to Step 4.
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Register the injector ID.
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STEP 4. M.U.T.-III data list.
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- Refer to Data List Reference Table
.
- Item 16: EGR valve position sensor
- Item 17: EGR valve target position
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Q.
Are the check results normal?
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Go to Step 5.
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Perform the diagnosis code classified check procedure for the sensor that has shown an abnormal data value (Refer to Inspection Chart for Diagnosis Code ).
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STEP 5. Check the using fuel.
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- Check for foreign matters (water, petrol fuel, etc.) in fuel
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Q.
Is the specified fuel being used?
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Go to Step 6.
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Replace the fuel.
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STEP 6. Check fuel supply line.
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- Check for fuel leakage and clogging.
- Check fuel filter for clogging.
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Q.
Is the check result normal?
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Go to Step 7.
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Repair.
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STEP 7. M.U.T.-III actuator test.
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- Refer to Actuator Test Reference Table
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- Item 19: Suction control valve
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Q.
Is the check result normal?
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Go to Step 8.
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Check suction control valve system (Refer to Code No. P0003 , Refer to Code No. P0004 ).
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STEP 8. M.U.T.-III data list.
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- Refer to Data List Reference Table
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- Item 63: Rail pressure sensor
- Item 64: Rail pressure target
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Q.
Are the check results normal?
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Go to Step 11.
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Go to Step 9.
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STEP 9. Replace the fuel pressure sensor.
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- After replacing the common-rail assembly, re-check the trouble symptoms.
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Q.
Does the trouble symptom persist?
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Go to Step 10.
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Check end.
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STEP 10. Check the trouble symptoms.
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Q.
Does the trouble symptom persist?
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Replace the supply pump assembly.
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
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STEP 11. Voltage measurement at engine-ECU connector (ALTF terminal).
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(1)Disconnect engine-ECU connector, and connect special tool power plant ECU check harness (MB992291) to measure at connector for inspection.
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(2)Engine: Idle operation after warm-up
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(4)Radiator fan: Not operated
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(5)Check the voltage between the engine-ECU connector (ALTF terminal) and body earth. OK: The voltage increases when the headlamp switch and the rear window defogger switch are turned ON from OFF.
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Q.
Is the check result normal?
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Go to Step 14.
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Go to Step 12.
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STEP 12. Check of open circuit, short to earth, and damage in ALTF line between engine-ECU connector and alternator connector.
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Q.
Is the check result normal?
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Go to Step 13.
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Repair the connector(s) or wiring harness.
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STEP 13. Check the trouble symptom.
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Q.
Does the trouble symptom persist?
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Replace the alternator.
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
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STEP 14. Check compression pressure.
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- Check compression pressure (Refer to GROUP 11E - On-vehicle Service - Compression Pressure Check
).
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Q.
Is the check result normal?
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Go to Step 15.
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Repair.
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STEP 15. Check valve clearance.
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- Check valve clearance (Refer to GROUP 11E - On-vehicle Service - Valve Clearance Check and Adjustment
).
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Q.
Is the check result normal?
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Go to Step 16.
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Adjust the valve clearance.
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STEP 16. M.U.T.-III actuator test.
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- Refer to Actuator Test Reference Table
.
- Item 15: Injector No. 1
- Item 16: Injector No. 2
- Item 17: Injector No. 3
- Item 18: Injector No. 4
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Q.
Are the check results normal?
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Go to Step 17.
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Check the injector system of the defective cylinder. (Refer to Code No. P0201: No. 1 Injector Circuit Malfunction ) (Refer to Code No. P0202: No. 2 Injector Circuit Malfunction ) (Refer to Code No. P0203: No. 3 Injector Circuit Malfunction ) (Refer to Code No. P0204: No. 4 Injector Circuit Malfunction )
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STEP 17. Check injector itself.
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- Check injector itself (Refer to
).
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Q.
Is the check result normal?
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Go to Step 18.
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Replace the injector at the failed cylinder.
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STEP 18. Check the trouble symptoms.
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Q.
Does the trouble symptom persist?
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Replace the engine-ECU.
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
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