Multiport Fuel Injection (MFI) Troubleshooting Strategy

TROUBLESHOOTING STRATEGY

NOTE:
If a DTC is erased, its "freeze frame" data will also be erased and system readiness test status will be reset. Store the "freeze frame" data before erasing the DTC.

Use these steps to plan your diagnostic strategy. If you follow them carefully, you will be sure to have exhausted most of the possible ways to find an MFI fault.
1. Gather as much information as possible about the complaint from the customer.
2. Verify that the condition described by the customer exists.
3. Check the vehicle for any MFI Diagnostic Trouble Code (DTC).
4. If you cannot verify the condition and there are no DTCs, the malfunction is intermittent.
For information on how to cope with intermittent malfunctions, refer to How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions How to Cope With Intermittent Malfunctions.
5. If you can verify the condition but there are no DTCs, or the system cannot communicate with the scan tool, refer to the trouble symptom classification table.
6. If there is a DTC, store the number of the code, then erase the code from the memory using the scan tool.
7. Reconfirm the malfunction symptom and carry out a test drive with the drive cycle pattern.
8. If DTC is set again, carry out an inspection with appropriate diagnostic trouble code procedures.
9. If DTC is not set again, the malfunction is intermittent. For information on how to cope with intermittent malfunctions, refer to How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions How to Cope With Intermittent Malfunctions.
10. After repairs are completed, conduct a road test duplicating the complaint set conditions to confirm the malfunction has been corrected.
11. Erase the permanent DTC. (Refer to Diagnostic Function - Permanent DTC for the procedures of erasing the permanent DTC Reading and Clearing Diagnostic Trouble Codes.)
NOTE:
This is carried out to prevent the failure to pass the Inspection and Maintenance (I/M) test in the states checking whether the permanent DTC is stored or not.