HEATED STEERING WHEEL SYSTEM Steering Wheel does not Heat Up When Heated Steering Wheel Switch is Pressed

DESCRIPTION

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WIRING DIAGRAM

A019KQGE01

INSPECTION PROCEDURE

Tech Tips


  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

  • The steering heater unit is built into the steering wheel assembly which cannot be disassembled. Therefore, when the steering heater unit has a malfunction, replace the steering wheel assembly.

PROCEDURE


  1. INSPECT STEERING WHEEL ASSEMBLY (THERMISTOR·HEATER·THERMOSTAT)


    1. A019M8ME01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Steering Wheel Control Assembly)

      Disconnect the B steering wheel controller connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      B-1 (TH1) - B-2 (TH2) 10 to 30°C (50 to 86°F) 8.132 to 18.43 kΩ
      B-4 (SH1) - B-3 (SH2) 20°C (68°F) 1.89 to 2.25 Ω

    NG

    REPLACE STEERING WHEEL ASSEMBLY Click here

    OK

  2. INSPECT SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY


    1. Check the connectors and cables of the spiral with sensor cable sub-assembly.

      OK
      There are no defects such as scratches, cracks, dents or damage on the connectors or cables.

    2. Disconnect the F100 and z14 spiral with sensor cable sub-assembly connectors.

      A019PCHE08

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      z14-1 (BTM) - F100-1 (BTM) Always Below 0.1 Ω
      z14-2 (ETM) - F100-3 (ETM) Always Below 0.1 Ω
      z14-3 (EHT) - F100-2 (EHT) Always Below 0.1 Ω
      z14-4 (BHT) - F100-4 (BHT) Always Below 0.1 Ω
      Text in Illustration
      *a

      Component without harness connected

      (Spiral with Sensor Cable Sub-assembly)

      		 - -

    NG

    REPLACE SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY Click here

    OK

  3. CHECK STEERING HEATER SWITCH


    1. A019N5QE02
      Text in Illustration
      *a

      Component without harness connected

      (Steering Heater Switch)

      Disconnect the F105 steering heater switch connector.

    2. Measure the voltage according to the value(s) in the table below.

      Tech Tips

      As the circuit has a diode, perform the measurement in diode test mode, and do not mistake the polarity.

      Standard Voltage

      Tester Connection

      (Positive (+) tester probe - Negative (-) tester probe)

      		 Condition Specified Condition
      F105-1 (IG) - F105-6 (IND) Always Below 1.25 V
      F105-5 (ECU) - F105-6 (IND) Steering heater switch is pushed Below 1.25 V

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      F105-1 (IG) - F105-5 (ECU) Steering heater switch is pushed Below 1 Ω
      F105-1 (IG) - F105-5 (ECU) Steering heater switch is not pushed 10 kΩ or higher

    NG

    REPLACE STEERING HEATER SWITCH Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (STEERING HEATER SWITCH - SPIRAL W/ SENSOR CABLE SUB-ASSEMBLY)


    1. Disconnect the F105 steering heater switch connector.

    2. Disconnect the F100 spiral with sensor cable sub-assembly connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      F105-6 (IND) - F100-1 (BTM) Always Below 1 Ω
      F105-5 (ECU) - F100-3 (ETM) Always Below 1 Ω
      F105-6 (IND) - Body ground Always 10 kΩ or higher
      F105-5 (ECU) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (STEERING HEATER SWITCH POWER SOURCE)


    1. Disconnect the F105 steering heater switch connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      F105-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (IG POWER SOURCE)


    1. Disconnect the F100 spiral with sensor cable sub-assembly connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      F100-4 (BHT) - Body ground Engine switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY BODY GROUND)


    1. Disconnect the F100 spiral with sensor cable sub-assembly connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      F100-2 (EHT) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE STEERING WHEEL HEATER CONTROL ASSEMBLY Click here