AIR CONDITIONING SYSTEM(for Automatic Air Conditioning System with Top-mounted Air Conditioner Pressure Sensor) PTC Heater Circuit

DESCRIPTION

The air conditioning amplifier assembly sends operation signals to the PTC heater relays when 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 Ignition switch ON
ECO mode: off
Blower switch: On
Temperature setting: MAX HOT
Light control switch off

  • Engine coolant temperature 65°C (149°F) or lower (3 PTC heater relays operating)

  • Engine coolant temperature 70°C (158°F) or lower (2 PTC heater relays operating)

  • Engine coolant temperature 75°C (167°F) or lower (1 PTC heater relay operating)

  • Ambient temperature -7°C (19°F) or lower (3 PTC heater relays operating)

  • Ambient temperature 16°C (61°F) or lower (2 PTC heater relays operating)

  • Ambient temperature 25°C (77°F) or lower (1 PTC heater relay operating)

WIRING DIAGRAM

A001U0BE05

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 (HEATER ACTIVE LEVEL)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch ON.

    3. Turn the GTS on.

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

    5. Perform the Active Test according to the display on the GTS.


      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. Remove the PTC heater relays.

    2. Inspect the PTC heater relays.

      Click here

      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
      PTC HTR NO. 1
      Tester Connection Switch 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
      Standard Voltage
      PTC HTR NO. 2
      Tester Connection Switch 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
      Standard Voltage
      PTC HTR NO. 3
      Tester Connection Switch 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
      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 F72 air conditioning amplifier assembly connectors.

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

      Standard Resistance
      PTC HTR NO. 1
      Tester Connection Condition Specified Condition
      Relay terminal 2 - F72-19 (PTC1) Always Below 1 Ω
      Relay terminal 2 or F72-19 (PTC1) - Body ground Always 10 kΩ or higher
      Standard Resistance
      PTC HTR NO. 2
      Tester Connection Condition Specified Condition
      Relay terminal 2 - F72-39 (PTC2) Always Below 1 Ω
      Relay terminal 2 or F72-39 (PTC2) - Body ground Always 10 kΩ or higher
      Standard Resistance
      PTC HTR NO. 3
      Tester Connection Condition Specified Condition
      Relay terminal 2 -F72-20 (PTC3) Always Below 1 Ω
      Relay terminal 2 or F72-20 (PTC3) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the H2 quick heater assembly connectors.

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

      Standard Resistance
      PTC HTR NO. 1
      Tester Connection Condition Specified Condition
      Relay terminal 5 - H2-3 (B) Always Below 1 Ω
      H2-2 (E) - Body ground Always Below 1 Ω
      H2-4 (E) - Body ground Always Below 1 Ω
      Relay terminal 5 or H2-3 (B) - Body ground Always 10 kΩ or higher
      Standard Resistance
      PTC HTR NO. 2
      Tester Connection Condition Specified Condition
      Relay terminal 5 - H2-1 (B) Always Below 1 Ω
      H2-2 (E) - Body ground Always Below 1 Ω
      Relay terminal 5 or H2-1 (B) - Body ground Always 10 kΩ or higher
      Standard Resistance
      PTC HTR NO. 3
      Tester Connection Condition Specified Condition
      Relay terminal 5 - H2-5 (B) Always Below 1 Ω
      H2-4 (E) - Body ground Always Below 1 Ω
      Relay terminal 5 or H2-5 (B) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT QUICK HEATER ASSEMBLY


    1. Remove the quick heater assembly.

      Click here

    2. Inspect the quick heater assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPLACE QUICK HEATER ASSEMBLY Click here