Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Detailed Flow
- OBTAIN INFORMATION ABOUT SYMPTOM
Interview the customer to obtain as much information as possible about the conditions and environment under which the malfunction occurs.
GO TO 2.
- CHECK DTC
- Check for DTC.
- If a DTC exists, perform the following operations.
- Records the DTCs.
- Erase DTCs
- Check that the root cause clarified with DTC matches to the malfunction information described by the customer.
- Check also the related service information or others.
Do malfunction information and or DTC exist?
Malfunction information and DTC exist.: GO TO 3.
Malfunction information exists but no DTC.: GO TO 4.
No malfunction information, but DTC exists.: GO TO 5.
- REPRODUCE THE MALFUNCTION INFORMATION
Check the malfunction described by the customer on the vehicle.
Record the status of each signal when a symptom occurs with "Data Monitor" in CONSULT-III.
Inspect the relation of the information and the condition when it occurs.
GO TO 5.
- CHECK THE MALFUNCTION
Check the malfunction described by the customer on the vehicle.
Record the status of each signal when a symptom occurs with "Data Monitor" in CONSULT-III.
Inspect the relation of the information and the condition when it occurs.
GO TO 6.
- PERFORM "DTC CONFIRMATION PROCEDURE"
Perform the "DTC conformation procedure" to the detected DTC and check that the DTC is detected again.
Refer to "DTC INSPECTION PRIORITY CHART " when multiple DTCs are detected, and then judge the order for performing the diagnosis.
Is any DTC detected?
YES: GO TO 7.
NO: Follow "HOW TO FOLLOW TEST GROUPS IN TROUBLE DIAGNOSIS " to check.
- IDENTIFY MALFUNCTIONING SYSTEM WITH "SYMPTOM DIAGNOSIS"
Use the "Symptom diagnosis" from the symptom inspection result in step 4. Then identify where to start performing the diagnosis based on the possible causes and the symptoms.
GO TO 7.
- IDENTIFY MALFUNCTIONING PARTS WITH "COMPONENT DIAGNOSIS"
Perform the inspection with the "component diagnosis" of the applicable system.
NOTE: The "component diagnosis" mainly consists of the check for an open circuit.The circuit check in the diagnosis procedure also requires the check for a short circuit. Refer to "CIRCUIT INSPECTION " for details.
GO TO 8.
- REPAIR OR REPLACE THE MALFUNCTIONING PARTS
- Repair or replace the part detected as malfunctioning.
- After repairing or replacing, reinstall/reconnect parts or connectors removed/disconnected in the "component diagnosis", and then erase the DTC.
GO TO 9.
- FINAL CHECK
Perform the "DTC confirmation procedure" or "Component Inspection" to check that the repair is correctly performed. Check that malfunctions are not reproduced when obtaining the malfunction information from the customer, referring to the symptom inspection result in step 3 or 4.
Is the check result normal?
YES: Trouble diagnosis is completed.
NO-1: The DTC is reproduced. GO TO 7.
NO-2: The symptom is reproduced. GO TO 6.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.