Diagnosis and repair workflow
Work Flow
Detailed flow
1.Interview from the customer
Clarify customer complaints before inspection. First of all, perform an interview utilizing stc-20, "diagnostic work sheet" and reproduce symptoms as well as fully understand it. Ask customer about his/her complaints carefully. Check symptoms by driving vehicle with customer, if necessary.
Caution:
Customers are not professional. Never guess easily like “maybe the customer means that...,” Or “maybe the customer mentions this symptom”.
>> Go to 2.
2.Check symptom
Reproduce the symptom that is indicated by the customer, based on the information from the customer obtained by interview. Also check that the symptom is not caused by protection function. Refer to STC-13, "Protection Function".
Caution:
When the symptom is caused by normal operation, fully inspect each portion and obtain the understanding of customer that the symptom is not caused by a malfunction.
>> Go to 3.
3.Perform self-diagnosis
With consult
Perform self-diagnosis.
Is any dtc detected? Yes >> record or print dtc and freeze frame data (ffd). Go to 4.
No >> go to 6.
4.Recheck symptom
With consult
Erase self-diagnostic results.
Perform dtc confirmation procedures for the malfunctioning system.
Note:
If some DTCs are detected at the same time, determine the order for performing the diagnosis based on STC- 14, "DTC Inspection Priority Chart".
Is any dtc detected? Yes >> go to 5.
No >> check harness and connectors based on the information obtained by interview. Refer to gi-39, "intermittent incident".
5.Repair or replace malfunctioning parts
Repair or replace malfunctioning parts
Reconnect part or connector after repairing or replacing.
When dtc is detected, erase self-diagnostic results for “eps”.
>> Go to 7.
6.Identify malfunctioning system by symptom diagnosis
Estimate malfunctioning system based on symptom diagnosis and perform inspection.
Can the malfunctioning system be identified?
Yes >> go to 7.
No >> check harness and connectors based on the information obtained by interview. Refer to gi-39, "intermittent incident".
7.Final check
With consult
Check the reference value for eps control unit.
Recheck the symptom and check that symptom is not reproduced on the same conditions.
Is the symptom reproduced? YES >> GO TO 3.
NO >> Inspection End.
Diagnostic Work Sheet
Description
In general, customers have their own criteria for a problem. Therefore, it is important to understand the symptom and status well enough by asking the customer about his/her concerns carefully. To systemize all the information for the diagnosis, prepare the interview sheet referring to the interview points.
In some cases, multiple conditions that appear simultaneously may cause a dtc to be detected.
Interview sheet sample


Wiring diagramPrecaution
Precaution for supplemental restraint system (srs) "air bag" and "seat belt
pre-tensioner"
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”,
used along
with a front seat belt, helps to reduce the risk or severity of injur ...
Power supply and ground circuit
Combination meter
Combination meter : diagnosis procedure
Regarding Wiring Diagram information, refer to MWI-28, "Wiring Diagram".
1.Check fuses
Check that the following fuses are not blown.
Is the fuse blown?
YES >> Replace the blown fuse after repairing the affected circu ...
Precaution for Work
When removing or disassembling each component, be careful not to damage
or deform it. If a component
may be subject to interference, be sure to protect it with a shop cloth.
When removing (disengaging) components with a screwdriver or similar
tool, be sure to wrap the component
with a ...