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.
CAN communication Line Inspection
- Connect all of control module (BCM, IPS, SMK, AVN) connector.
- Ignition "ON", ENG "OFF"
- Set-up the oscilloscope as mentioned below.
- Back probe and measure signal waveform of Pin No. 11 (Low) terminal of SMK Module connector and chassis ground.
- Back probe and measure signal waveform of Pin No. 10 (High) terminal of SMK Module connector and chassis ground.
Specification: Refer to Fig 1 below
- Is the measured signal waveform normal?
YES
- Check BCM, IPS, SMK, AVN and Each Module connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.
NO
- If the measured value is battery voltage, check short to battery in CAN line. Repair or replace as necessary. And then, go to "VERIFICATION OF VEHICLE REPAIR " procedure. In case that Communication is in sleep mode, 12V will be measured. Therefore, check that communication is in Wake up status.
- If 0V is detected, Check short to ground, short between CAN high and low each other or open in CAN high or CAN low harness. Repair or replace as necessary and then, go to "VERIFICATION OF VEHICLE REPAIR " procedure.
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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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