AIR CONDITIONING SYSTEM PTC Heater Circuit

DESCRIPTION

The PTC heater assembly is installed in the radiator in the heater unit and operates when engine coolant temperature is low and normal heater effectiveness is insufficient.

The A/C control assembly switches the circuit in the PTC relay and operates the PTC heater assembly when the operating conditions (cooling water temperature is below 65°C (149°F), setting temperature is MAX. HOT, ambient temperature is below 10°C (50°F) and blower switch is not OFF) are met.

The PTC heater assembly controls PTC heater lines by electric load or the amount of inverter with converter assembly (PCU) output. Therefore, troubleshooting should be performed with other electric components off.

WIRING DIAGRAM

A01JAO7E02

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT PTC HEATER ASSEMBLY


    1. A01JB3QE16
      Text in Illustration
      *1

      Component without harness connected

      (PTC Heater Assembly)

      Remove the PTC heater assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A19-1 (B) - A20-1 (E) Always Below 1 Ω
      A19-2 (B) - A20-2 (E) Always Below 1 Ω
      A19-2 (B) - A20-1 (E) Always Below 1 Ω
      A19-3 (B) - A20-2 (E) Always Below 1 Ω

    NG

    REPLACE PTC HEATER ASSEMBLY Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (PTC HEATER ASSEMBLY - BODY GROUND)


    1. A01JB1QE02
      Text in Illustration
      *1

      Front view of wire harness connector

      (to PTC Heater Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A20-1 (E) - Body ground Always Below 1 Ω
      A20-2 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (PTC HEATER ASSEMBLY - INTEGRATION RELAY)


    1. A01JAQIE03

      Disconnect the PTC heater assembly connector.

    2. A01JA2ZE01

      Disconnect the engine room relay block and junction block (integration relay) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A19-1 (B) - 1H-10 (PTC1) Always Below 1 Ω
      A19-2 (B) - 1H-8 (PTC2) Always Below 1 Ω
      A19-3 (B) - 1H-9 (PTC3) Always Below 1 Ω
      A19-1 (B) - Body ground Always 10 kΩ or higher
      A19-2 (B) - Body ground Always 10 kΩ or higher
      A19-3 (B) - Body ground Always 10 kΩ or higher
      Text in Illustration
      *1

      Front view of wire harness connector

      (to PTC Heater Assembly)
      *2

      Front view of wire harness connector

      (to Engine Room Relay Block and Junction Block (Integration Relay))

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - INTEGRATION RELAY)


    1. A01JAUIE73

      Disconnect the A/C amplifier connector.

    2. A01J9B9E01

      Disconnect the engine room relay block and junction block (integration relay) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L17-18 (PTC1) - 1G-17 (PTCA) Always Below 1 Ω
      L17-38 (PTC2) - 1G-26 (PTCB) Always Below 1 Ω
      L17-16 (PTC3) - 1G-25 (PTCC) Always Below 1 Ω
      L17-18 (PTC1) - Body ground Always 10 kΩ or higher
      L17-38 (PTC2) - Body ground Always 10 kΩ or higher
      L17-16 (PTC3) - Body ground Always 10 kΩ or higher
      Text in Illustration
      *1

      Front view of wire harness connector

      (to A/C Amplifier)
      *2

      Front view of wire harness connector

      (to Engine Room Relay Block and Junction Block (Integration Relay))

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. REPLACE INTEGRATION NO.1 RELAY


    1. Replace the integration relay Click here.

      Tech Tips

      Since the integration relay cannot be inspected while it is removed from the vehicle, replace the integration relay with a new or a 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 (INTEGRATION RELAY WAS DEFECTIVE)