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.
How To Proceed With Troubleshooting
Troubleshoot in accordance with the procedure on the following pages.
- VEHICLE BROUGHT IN
- CUSTOMER PROBLEM ANALYSIS CHECK AND SYMPTOM CHECK (See CUSTOMER PROBLEM ANALYSIS CHECK )
- INSPECT COMMUNICATION FUNCTION OF LARGE-SCALE BODY MULTIPLEX COMMUNICATION SYSTEM (BEAN)
- Check that there is no abnormality in the communication system by inspecting the communication function of the body multiplex communication system with the hand-held tester.
- (ECU unconnected, communication line abnormal) Without code outputs, proceed to "A".
- (ECU unconnected, communication line abnormal) With code outputs, proceed to "B".
B: GO TO HOW TO PROCEED WITH TROUBLESHOOTING )
A
- Check that there is no abnormality in the communication system by inspecting the communication function of the body multiplex communication system with the hand-held tester.
- (See DIAGNOSTIC TROUBLE CODE CHART
)
- Check a DTC and note it if a code is output.
- Delete the DTC.
- Check if the DTC will be output once again, when the problem symptom is simulated based on the noted code.
- Without an output of the code, proceed to "A".
- With an output of the code, proceed to "B".
B: Go to step 7
A
- (See PROBLEM SYMPTOMS TABLE
)
- Without an applicable symptoms table, proceed to "A".
- With an applicable symptoms table, proceed to "B".
B: Go to step 7
A
- ACCORDING TO PROBLEM SYMPTOM, PERFORM TROUBLESHOOTING
- (See ON-VEHICLE INSPECTION )
- (See PRE-CHECK
)
- Inspection with the hand-held tester (ECU data list)
- Inspection with the hand-held tester (Active test)
- (See TERMINALS OF ECU )
- ADJUSTMENT, REPAIR OR REPLACE
END
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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.
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