Explanation of Troubleshooting Procedures

Effective troubleshooting procedures for MFI system problems are given below.
1. Verification of trouble symptom
- Reproduce trouble symptom and verify the characteristics of the trouble and the conditions (engine condition, driving conditions, etc.) under which it Is produced.
2. Reading of diagnostic trouble code
- Read diagnostic trouble code and if a malfunction code is output, locate and correct the trouble referring to the DIAGNOSIS CHART.
3. Estimation of the causes of trouble and setting of check items
- Referring to the Check Chart, verify the check items and checking order for the trouble symptom.
4. Inspection of engine control module input/output signals
- Using the scan tool or oscilloscope, check the engine control module input/output signals.
- If the signals are normal, judge the sensor input/actuator control as normal and proceed to check the input/output signals of the next check item.
5. Inspection of MFI system component harness
- If the engine control module input/output signals are abnormal, check the MFI system component body harness and repair as necessary.
- After repair, check the engine control module input/output signals again. If they are normal, proceed to check the input/output signals of the next check item.
6. Inspection of individual MFI system components
- If the body harness is normal but the engine control module input/output signals are abnormal, check individual MFI system components and repair or replace as necessary.
- After repair or replacement, check the engine control module input/output signals again. If they are normal, proceed to check the input/output signals of the next check item.
7. Re-inspection and repair of trouble symptom
- If the harness inspection and individual component inspection results are normal but the engine control module input/output signals are abnormal, re-examine the causes of trouble referring to the troubleshooting hints and the checks and repairs included in other groups.
8. Verification and prevention of reoccurrence after repair
- Perform tests to see if the same problems occur again and make sure that the same problems will not be repeated.
- Remove the true causes of the trouble to prevent its reoccurrence.