Diagnostic Strategies

1. Reproduce the Symptom
- Reproduce the problem symptom and check the contents of the trouble and the conditions under which the Symptom occurs (engine condition, operating state, etc.).

2. Read Diagnostic Trouble Codes
- Read the diagnostic trouble codes and when a fault code is output, correct the fault.

3. Note the Possible Causes and Plan a Strategy to Determine the Actual Cause of the Problem.
- List the items to check and the order of procedures to be followed.

4. Check Engine Control Module Input Signals
- Using a scan tool or analyzer, check the input signals of the engine control module.
- If the input signals are normal, the sensor input control is judged as normal--check the following items.

5. Check Engine Control Module Output Signals And Actuator Operation
- Using a scan tool, check the output signals of the engine control module. Also drive the actuator with the actuator testing function to check operation of the actuator.
- Using the analyzer, check the output signals of the engine control module.
- If the Output signals of the engine control module and the operation of the actuator are normal, the actuator control is judged as normal--check the following items.

6. Checking Individual MFI System Components
- If the body harnesses are normal but the input and output signals of the engine control module are abnormal, check the MFI system components individually and repair or replace as necessary.
- After repair or replacement, check the input and output signals of the engine control module again. If they are normal this time--check the input and output signals of the next check item.

7. Examining Causes Of Trouble And Checking And Repairing
- If the harness check and individual component check have resulted normal but the Input and Output signals of the engine control module are abnormal, examine the causes of trouble. Then, check and repair including other groups.

8. Confirming Completion Of Repair And Preventing Reoccurrence;
- Try to reproduce the problem/symptom to make sure that it will not occur again.