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

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DESCRIPTION

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WIRING DIAGRAM


C234292E02


INSPECTION PROCEDURE

HINT:
  1. Inspect the fuses for circuits related to this system before performing the following inspection procedure.
  2. 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.

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


    C234543E01

  1. Disconnect the B steering wheel controller connector.

  1. 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

    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Steering Wheel Control Assembly)



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.



  1. Disconnect the H45 and z14 spiral with sensor cable sub-assembly connectors.


    C233762E02

  1. Disconnect the heated steering wheel controller connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    z14-1 (CCU) - H45-1 (BTM)
    		Always
    		Below 1 Ω
    z14-2 (CCV) - H45-3 (ETM)
    		Always
    		Below 1 Ω
    z14-3 (CCX) - H45-2 (EHT)
    		Always
    		Below 1 Ω
    z14-4 (CCW) - H45-4 (BHT)
    		Always
    		Below 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


    C233764E01

  1. Disconnect the H42 steering heater switch connector.

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

    HINT:
    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
    H42-3 (IG) - H42-7 (+)
    		Always
    		Below 1.25 V
    H42-6 (IN) - H42-7 (+)
    		Steering heater switch is pushed
    		Below 1.25 V

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    H42-3 (IG) - H42-6 (IN)
    		Steering heater switch is pushed
    		Below 1 Ω
    H42-3 (IG) - H42-6 (IN)
    		Steering heater switch is not pushed
    		10 kΩ or higher

Text in Illustration 
*a
Component without harness connected
(Steering Heater Switch)


NG
REPLACE STEERING HEATER SWITCH (Click here)
OK


4.CHECK STRG HTR RELAY (STEERING HEATER RELAY)


    C234546E02

  1. Remove the STRG HTR relay (steering heater relay).

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    3 - 5
    		Voltage is not applied between terminals 1 and 2
    		10 kΩ or higher
    3 - 5
    		Voltage is applied between terminals 1 and 2
    		Below 1 Ω

    Text in Illustration 
    *1
    		STRG HTR Relay (Steering Heater Relay)



NG
REPLACE STRG HTR RELAY (STEERING HEATER RELAY)
OK


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

  1. Disconnect the H42 steering heater switch connector.

  1. Disconnect the H45 spiral with sensor cable sub-assembly connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    H42-7 (+) - H45-1 (BTM)
    		Always
    		Below 1 Ω
    H42-6 (IN) - H45-3 (ETM)
    		Always
    		Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


6.CHECK HARNESS AND CONNECTOR (STRG HTR RELAY - SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY)

  1. Remove the STRG HTR relay (steering heater relay) from the relay block No. 3.

  1. Disconnect the H45 spiral with sensor cable sub-assembly connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    Relay block No. 3 - 5 - H45-4 (BHT)
    		Always
    		Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


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

  1. Disconnect the H42 steering heater switch connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    H42-3 (IG) - Body ground
    		Power switch on (IG)
    		11 to 14 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


8.CHECK HARNESS AND CONNECTOR (STRG HTR RELAY (STEERING HEATER RELAY) POWER SOURCE)

  1. Remove the STRG HTR relay (steering heater relay) from the relay block No. 3.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    Relay block No. 3-3 - Body ground
    		Always
    		11 to 14 V
    Relay block No. 3-1 - Body ground
    		Power switch on (IG)
    		11 to 14 V

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    Relay block No. 3-2 - Body ground
    		Always
    		Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


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

  1. Disconnect the H45 spiral with sensor cable sub-assembly connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    H45-2 (EHT) - Body ground
    		Always
    		Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE STEERING WHEEL HEATER CONTROL ASSEMBLY (Click here)