How to Perform Trouble Diagnosis

TROUBLE DIAGNOSIS


How to Perform Trouble Diagnosis


BASIC CONCEPT
- To perform trouble diagnosis, it is the must to have understanding about vehicle systems (control and mechanism) thoroughly.





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

CAUTION:
Customers are not professionals. It is dangerous to make an easy guess like "maybe the customer means that..." or "maybe the customer mentions this symptom".





- It is essential to check symptoms right from the beginning in order to repair malfunctions completely.
For intermittent malfunctions, reproduce symptoms 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 repairing without any symptom diagnosis, you cannot judge if malfunctions has actually been eliminated.

PRECAUTIONS FOR TROUBLE DIAGNOSIS
- Be sure to check the procedures of the trouble diagnosis in advance. Refer to "How to Perform Trouble
Diagnosis".
- Always erase memory after completing trouble diagnosis.
- Checking continuity and voltage between units, be sure to check connector terminals for disconnection, looseness, bend, or collapse. Repair or replace applicable part if any non-standard condition is detected.
- Be careful not to forcibly extend any connector terminal if a circuit tester is used for the check.
- Always confirm the general precautions. Refer to General Precaution.

INTERVIEW
- Complaints vary depending on the person. It is important to clarify the customer's actual remarks.





- Ask the customer about what symptoms occur under what conditions. Use the information to reproduce the symptom of confirm by vehicle.