AIR CONDITIONING SYSTEM PTC Heater Circuit

DESCRIPTION

The air conditioning amplifier assembly sends operation signals to the No. 1 integration relay when the quick heater assembly (PTC heater) operation conditions are met. Based on the signals from the air conditioning amplifier assembly, the relays in the No. 1 integration relay turn on, and power is supplied to the quick heater assembly (PTC heater) installed in the air conditioning radiator assembly.

Quick Heater Assembly (PTC Heater) Operation Condition
Control ECU Condition
Air Conditioning Amplifier Assembly Blower motor on
Temperature set to MAX HOT
ECO switch off

IDH terminal signal less than 1 V

(Inverter with converter assembly overload not detected)
Coolant temperature 55°C or lower
Ambient temperature 10°C or lower

WIRING DIAGRAM

A0044AZE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. PERFORM ACTIVE TEST USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    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.

      Air Conditioner
      Tester Display Test Part Control Range Diagnostic Note
      Heater Active Level Quick heater assembly Min.: 0, Max.: 3 -
      OK
      Heater Active Level changes normally.

    NG

    INSPECT QUICK HEATER ASSEMBLY Click here

    OK

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

  2. INSPECT QUICK HEATER ASSEMBLY


    1. A0042DLE07
      Text in Illustration
      *a

      Component without harness connected

      (Quick Heater Assembly)

      Remove the quick heater assembly Click here.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A18-3 (B) - A19-2 (E) Always Below 1 Ω
      A18-2 (B) - A19-2 (E) Always Below 1 Ω
      A18-2 (B) - A19-1 (E) Always Below 1 Ω
      A18-1 (B) - A19-1 (E) Always Below 1 Ω

    NG

    REPLACE QUICK HEATER ASSEMBLY Click here

    OK

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


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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A19-1 (E) - Body ground Always Below 1 Ω
      A19-2 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (QUICK HEATER ASSEMBLY - NO. 1 INTEGRATION RELAY)


    1. Disconnect the A18 quick heater assembly connector.

    2. Disconnect the 1H No. 1 integration relay connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A18-1 (B) - 1H-10 (PTC1) Always Below 1 Ω
      A18-2 (B) - 1H-8 (PTC2) Always Below 1 Ω
      A18-3 (B) - 1H-9 (PTC3) Always Below 1 Ω
      A18-1 (B) - Body ground Always 10 kΩ or higher
      A18-2 (B) - Body ground Always 10 kΩ or higher
      A18-3 (B) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - POWER SOURCE)


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

      Standard Voltage
      Tester Connection Condition Specified Condition
      1G-14 (IG1) - Body ground Power switch off Below 1 V
      1G-14 (IG1) - Body ground Power switch on (IG) 11 to 14 V
      1H-7 (BATT) - Body ground Power switch off 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - BODY GROUND)


    1. Disconnect the 1G No. 1 integration relay connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1G-22 (GND1) - Body ground Always Below 1 Ω
      1H-3 (GND2) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - NO. 1 INTEGRATION RELAY)


    1. Disconnect the L14 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L14-18 (PTC1) - 1G-17 (PTCA) Always Below 1 Ω
      L14-38 (PTC2) - 1G-26 (PTCB) Always Below 1 Ω
      L14-16 (PTC3) - 1G-25 (PTCC) Always Below 1 Ω
      L14-18 (PTC1) - Body ground Always 10 kΩ or higher
      L14-38 (PTC2) - Body ground Always 10 kΩ or higher
      L14-16 (PTC3) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK NO. 1 INTEGRATION RELAY


    1. Replace the No. 1 integration relay Click here.

      Tech Tips

      Since the No. 1 integration relay cannot be inspected while it is removed from the vehicle, replace the No. 1 integration relay with a new or known good one and check that the condition returns to normal.

    2. Check if the same problem occurs again.

      OK
      Same problem does not occur.

    NG

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

    OK

    END (NO. 1 INTEGRATION RELAY WAS DEFECTIVE)