AIR CONDITIONING SYSTEM(for Manual Air Conditioning System) PTC Heater Circuit

DESCRIPTION

The air conditioning amplifier assembly sends operation signals to the PTC heater relays when the quick heater assembly operation conditions are met. Based on the signals from the air conditioning amplifier assembly, the PTC heater relays turn on, and power is supplied to the quick heater assembly installed in the air conditioning radiator assembly.

Quick Heater Assembly Operation Condition
Control ECU Condition
Air Conditioning Amplifier Assembly Engine running
Blower switch: On
Temperature settings: MAX HOT
Light control switch assembly off

  • Engine coolant temperature: 65°C or lower (3 PTC heater relays operating)

  • Engine coolant temperature: 70°C or lower (2 PTC heater relays operating)

  • Engine coolant temperature: 75°C or lower (1 PTC heater relay operating)
Ambient temperature: 10°C or lower

WIRING DIAGRAM

A01TCO2E02
A01T8SIE02

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. PERFORM ACTIVE TEST USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Air Conditioner / Active Test.

    5. Check the operation by referring to the table below.


      Body Electrical > Air Conditioner > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Heater Active Level Quick heater assembly Min.: 0, Max.: 3 -

      Body Electrical > Air Conditioner > Active Test
      Tester Display
      Heater Active Level
      OK
      Heater Active Level changes normally.
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  2. INSPECT PTC HEATER RELAY


    1. for PTC heater 600W type.


      1. Remove the PTC heater relays.

        A01TCXFC01
        *a

        Component without harness connected

        (HTR SUB NO. 1 Relay)
        *b

        Component without harness connected

        (HTR SUB NO. 2 Relay)
        *c

        Component without harness connected

        (HTR SUB NO. 3 Relay)

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

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

    2. for PTC heater 495W type.


      1. Remove the PTC heater relays.

        A01T9ASC01
        *a

        Component without harness connected

        (HTR SUB NO. 1 Relay and HTR SUB NO. 2 Relay)
        *b

        Component without harness connected

        (HTR SUB NO. 3 Relay)

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        3 - 5 Battery voltage is not applied between terminals 1 and 2 10 kΩ or higher
        3 - 5 Battery voltage is applied between terminals 1 and 2 Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE PTC HEATER RELAY

    OK

  3. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - POWER SOURCE)


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

      Standard Voltage
      HTR SUB NO. 1
      Tester Connection Condition Specified Condition
      Relay terminal 5 - Body ground*1 Always 11 to 14 V
      Relay terminal 3 - Body ground*2 Always 11 to 14 V
      Relay terminal 1 - Body ground*1 Ignition switch off Below 1 V
      Relay terminal 1 - Body ground*1 Ignition switch ON 11 to 14 V
      Relay terminal 2 - Body ground*2 Ignition switch off Below 1 V
      Relay terminal 2 - Body ground*2 Ignition switch ON 11 to 14 V
      Standard Voltage
      HTR SUB NO. 2
      Tester Connection Condition Specified Condition
      Relay terminal 3 - Body ground Always 11 to 14 V
      Relay terminal 2 - Body ground Ignition switch off Below 1 V
      Relay terminal 2 - Body ground Ignition switch ON 11 to 14 V
      Standard Voltage
      HTR SUB NO. 3
      Tester Connection Condition Specified Condition
      Relay terminal 3 - Body ground Always 11 to 14 V
      Relay terminal 1 - Body ground Ignition switch off Below 1 V
      Relay terminal 1 - Body ground Ignition switch ON 11 to 14 V

      • *1: for PTC Heater 600W Type

      • *2: for PTC Heater 495W Type

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - AIR CONDITIONING AMPLIFIER ASSEMBLY)


    1. Disconnect the E62 air conditioning amplifier assembly connector.

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

      Standard Resistance
      HTR SUB NO. 1
      Tester Connection Condition Specified Condition
      Relay terminal 2 - E62-13 (PTC1)*1 Always Below 1 Ω
      Relay terminal 1 - E62-13 (PTC1)*2 Always Below 1 Ω
      E62-13 (PTC1) - Body ground Always 10 kΩ or higher
      Standard Resistance
      HTR SUB NO. 2
      Tester Connection Condition Specified Condition
      Relay terminal 1 - E62-19 (PTC2) Always Below 1 Ω
      E62-19 (PTC2) - Body ground Always 10 kΩ or higher
      Standard Resistance
      HTR SUB NO. 3
      Tester Connection Condition Specified Condition
      Relay terminal 2 - E62-20 (PTC3) Always Below 1 Ω
      E62-20 (PTC3) - Body ground Always 10 kΩ or higher

      • *1: for PTC Heater 600W Type

      • *2: for PTC Heater 495W Type

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - QUICK HEATER ASSEMBLY)


    1. Disconnect the A6 quick heater assembly connector.

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

      Standard Resistance
      HTR SUB NO. 1
      Tester Connection Condition Specified Condition
      Relay terminal 3 - A6-2 (B)*1 Always Below 1 Ω
      A6-2 (B) - Body ground*1 Always 10 kΩ or higher
      Relay terminal 5 - A6-1 (B)*2 Always Below 1 Ω
      A6-1 (B) - Body ground*2 Always 10 kΩ or higher
      Standard Resistance
      HTR SUB NO. 2
      Tester Connection Condition Specified Condition
      Relay terminal 5 - A6-1 (B)*1 Always Below 1 Ω
      A6-1 (B) - Body ground*1 Always 10 kΩ or higher
      Relay terminal 5 - A6-2 (B)*2 Always Below 1 Ω
      A6-2 (B) - Body ground*2 Always 10 kΩ or higher
      Standard Resistance
      HTR SUB NO. 3
      Tester Connection Condition Specified Condition
      Relay terminal 5 - A6-3 (B) Always Below 1 Ω
      A6-3 (B) - Body ground Always 10 kΩ or higher

      • *1: for PTC Heater 600W Type

      • *2: for PTC Heater 495W Type

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (QUICK HEATER ASSEMBLY - BODY GROUND)


    1. Disconnect the A7 quick heater assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A7-1 (E) - Body ground Always Below 1 Ω
      A7-2 (E) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. INSPECT QUICK HEATER ASSEMBLY


    1. A01TC2SC07
      *a

      Component without harness connected

      (Quick Heater Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A6-1 (B) - A7-1 (E) Always Below 1 Ω
      A6-2 (B) - A7-1 (E) Always Below 1 Ω
      A6-2 (B) - A7-2 (E) Always Below 1 Ω
      A6-3 (B) - A7-2 (E) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPLACE QUICK HEATER ASSEMBLY Click here