COMBUSTION TYPE POWER HEATER SYSTEM Power Heater Switch Circuit

DESCRIPTION

When the power heater switch is turned on, the power heater ECU (combustion heater assembly) sends a drive signal to the heater pump assembly. The combustion heater then receives fuel necessary for combustion and starts operating.

WIRING DIAGRAM

A01177WE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. INSPECT POWER HEATER SWITCH


    1. A011A4PE01
      Text in Illustration
      *1

      Component without harness connected

      (Power Heater Switch)

      Measure the resistance.


      1. Remove the power heater switch.

      2. Disconnect the D9 power heater switch connector.

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

        Standard Resistance
        Tester Connection Switch Condition Specified Condition
        4 (IG) - 1 (IN) Power heater switch on Below 1 Ω
        4 (IG) - 1 (IN) Power heater switch off 10 kΩ or higher

    2. Check that the power heater switch operation indicator comes on.


      1. Connect the positive (+) lead from the battery to terminal 1 (IN) and the negative (-) lead to terminal 5 (E), and check that the operation indicator comes on.

        OK
        Indicator comes on.

    3. Check that the power heater switch illumination comes on.


      1. Connect the positive (+) lead from the battery to terminal 3 (ILL+) and the negative (-) lead to terminal 2 (ILL-), and check that the switch illumination comes on.

        OK
        Illumination comes on.

    4. Install the power heater switch.

    5. Reconnect the power heater switch connector.


    NG

    REPLACE POWER HEATER SWITCH Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (POWER HEATER SWITCH - BODY GROUND)


    1. A011B09E01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Power Heater Switch)

      Disconnect the D9 power heater switch connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D9-5 (E) - Body ground Always Below 1 Ω

    3. Reconnect the power heater switch connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (POWER HEATER ECU (COMBUSTION HEATER ASSEMBLY) - BATTERY)


    1. A01194QE03
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Power Heater ECU (Combustion Heater Assembly))

      Disconnect the A45 power heater ECU (combustion heater assembly) connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A45-3 (IG) - Body ground

      Ignition switch ON

      Power heater switch on

      		 11 to 14 V
      A45-3 (IG) - Body ground

      Ignition switch ON

      Power heater switch off

      		 Below 1 V

    3. Reconnect the power heater ECU (combustion heater assembly) connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here