How to Perform Trouble Diagnosis

TROUBLE DIAGNOSIS


How to Perform Trouble Diagnosis


BASIC CONCEPT
- The most important point to perform trouble diagnosis is to understand systems (control and mechanism) in vehicle thoroughly.





- It is also important to clarify customer complaints before inspection.
First of all, reproduce symptom, and understand it fully.
Ask customer about his/her complaints carefully. In some cases, they will be necessary to check symptom by driving vehicle with customer.

CAUTION:
Customers are not professionals. Do not assume "maybe customer means..." or "maybe customer mentioned this symptom".





- It is essential to check symptoms right from beginning in order to repair a malfunction completely.
For an intermittent malfunction, it is important to reproduce symptom based on interview with customer and past examples. Do not perform inspection on ad hoc basis. Most intermittent malfunctions are caused by poor contacts. In this case, it will be effective to shake suspected harness or connector by hand. When repairs are performed without any symptom check, no one can judge if malfunction has actually been eliminated.
- After diagnostic, make sure to perform "ERASE MEMORY". Refer to Scan Tool Testing and Procedures.
- Always read "GI General Information" to confirm general precautions. Refer to General Precaution.

DIAGNOSIS FLOW CHART

Diagnosis Flow Chart:

ASKING COMPLAINTS
- Complaints against malfunction vary depending on each person. It is important to clarify customer complaints.





- Ask customer about what symptoms are present and under what conditions. Use information to reproduce symptom while driving.
- It is also important to use diagnostic sheet so as not to miss information.

EXAMPLE OF DIAGNOSIS WORKSHEET

Example Of Diagnosis Worksheet: