Inspection Procedure
2: The indicator for the heated steering wheel switch does not come on.
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COMMENTS ON TROUBLE SYMPTOM
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If the illumination lamp does not come on after the heated steering wheel switch is turned
on, a component of the heated steering wheel, the power supply lines to the heated steering wheel
or the indicator illumination circuit lines to the heated steering wheel switch may be defective.
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- Malfunction of heated steering wheel switch
- Malfunction of clock spring
- Defective steering wheel (incorporating heated steering wheel-ECU and heater element)
- Defective harness wire(s) or connector(s)
- Open circuit between the body earth and the heated steering wheel relay or
loose connector contact
- Short or open circuit between the ETACS-ECU and the heated steering wheel-ECU or
loose connector contact
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STEP 1. Check the heated steering wheel switch.
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Check the heated steering wheel switch (Refer to  ).
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Q.
Is the check result normal?
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 Go to Step 2.
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 Replace the heated steering wheel switch (Refer to ).
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STEP 2. Check the clock spring.
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Check whether the clock spring is in good condition.
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Q.
Is the check result normal?
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Go to Step 3.
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Replace the clock spring.
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STEP 3. Voltage measurement at the heated steering wheel-ECU connector
(LED terminal)
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(1) Measure the heated steering wheel-ECU voltage with disconnecting the connector.
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(2)Set the ignition switch or engine switch to ON.
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(3)Set the heated steering wheel switch to ON.
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(4)Measure the voltage between the heated steering wheel-ECU connector (LED terminal)
and the body earth.
OK: Approximately system voltage
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Q.
Is the check result normal?
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Go to Step 5.
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Go to Step 4.
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STEP 4. Check of short to power supply, short to earth, and open circuit
in LED line between heated steering wheel switch connector and heated steering wheel-ECU connector
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Q.
Is the check result normal?
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Intermittent malfunction.
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Repair the connector(s) or wiring harness.
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STEP 5. Retest the system
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Q.
Is the check result normal?
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This diagnosis is complete.
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Replace the heated steering wheel ECU (Refer to ).
Then go to Step 6.
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STEP 6. Retest the system
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Q.
Is the check result normal?
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This diagnosis is complete.
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Replace the steering wheel (Refer to ).
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