AIR CONDITIONING SYSTEM 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 Start the engine
Integration control and panel assembly (ECO mode switch) off
Blower switch: on
Temperature settings: 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 (A PTC heater relay operating)
Ambient temperature 10°C (50°F) or lower

WIRING DIAGRAM

A01HINGE11

CAUTION / NOTICE / HINT

Note


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

  • If the battery voltage is low, the PTC heater, seat heater system (w/ Seat Heater System) and climate control seat system (w/ Climate Control Seat System) may not operate. When "High Power Consumption Partial Limit On AC/Heater Operation." is displayed on the multi-information display in the combination meter assembly, inspect the battery, referring to On-vehicle Inspection for the charging system.

    for 8AR-FTS:

    Click here

    for 3ZR-FAE:

    Click here

    Tech Tips

    If the battery voltage is low, "Operation Limitation Control History Count (Level 1)" and "Operation Limitation Control History Count (Level 2) is counted.

    Click here

  • If the battery voltage is low, the PTC heater may not operate. Refer to Data List for the power steering system.

    for Manual Tilt and Manual Telescopic Steering Column:

    Click here

    for Power Tilt and Power Telescopic Steering Column:

    Click here

  • When the battery is disconnected or the air conditioning amplifier assembly is replaced, be sure to perform servo motor initialization.

    Click here

PROCEDURE


  1. PERFORM ACTIVE TEST USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the engine 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.


      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 (PTC HTR NO.1, PTC HTR NO.2, PTC HTR NO.3)


    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. A01HGZ9C01
      *a

      Component without harness connected

      (PTC Heater NO.2 Relay)
      *b

      Component without harness connected

      (PTC Heater NO.1 Relay)
      *c

      Component without harness connected

      (PTC Heater NO.3 Relay)

      Remove the PTC heater relays.

    2. 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 Engine switch off 11 to 14 V
      Relay terminal 1 - Body ground Engine switch off Below 1 V
      Relay terminal 1 - Body ground Engine switch on (IG) 11 to 14 V
      PTC HTR NO.2
      Tester Connection Switch Condition Specified Condition
      Relay terminal 3 - Body ground Engine switch off 11 to 14 V
      Relay terminal 2 - Body ground Engine switch off Below 1 V
      Relay terminal 2 - Body ground Engine switch on (IG) 11 to 14 V
      PTC HTR NO.3
      Tester Connection Switch Condition Specified Condition
      Relay terminal 3 - Body ground Engine switch off 11 to 14 V
      Relay terminal 1 - Body ground Engine switch off Below 1 V
      Relay terminal 1 - Body ground Engine switch on (IG) 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. Remove the PTC heater relays.

    2. Disconnect the I50 air conditioning amplifier assembly connector.

    3. 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 - I50-3 (PTC2) Always Below 1 Ω
      Relay terminal 2 or I50-3 (PTC2)- Body ground Always 10 kΩ or higher
      PTC HTR NO.2
      Tester Connection Condition Specified Condition
      Relay terminal 1 - I50-40 (PTC1) Always Below 1 Ω
      Relay terminal 1 or I50-40 (PTC1) - Body ground Always 10 kΩ or higher
      PTC HTR NO.3
      Tester Connection Condition Specified Condition
      Relay terminal 2 - I50-19 (PTC3) Always Below 1 Ω
      Relay terminal 2 or I50-19 (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. Remove the PTC heater relays.

    2. Disconnect the I14 and I15 quick heater assembly connectors.

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

      Standard Resistance
      PTC HTR NO.1
      Tester Connection Condition Specified Condition
      I14-1 (B) - Relay terminal 5 Always Below 1 Ω
      I14-2 (E) - Body ground Always Below 1 Ω
      I14-1 (B) or Relay terminal 5 - Body ground Always 10 kΩ or higher
      PTC HTR NO.2
      Tester Connection Condition Specified Condition
      I14-3 (B) - Relay terminal 5 Always Below 1 Ω
      I14-2 (E) - Body ground Always Below 1 Ω
      I15-1 (E) - Body ground Always Below 1 Ω
      I14-3 (B) or Relay terminal 5 - Body ground Always 10 kΩ or higher
      PTC HTR NO.3
      Tester Connection Condition Specified Condition
      I15-2 (B) - Relay terminal 5 Always Below 1 Ω
      I15-1 (E) - Body ground Always Below 1 Ω
      I15-2 (B) or Relay terminal 5 - 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.

      for LHD:

      Click here

      for RHD:

      Click here

    2. Inspect the quick heater assembly.

      for LHD:

      Click here

      for RHD:

      Click here

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPLACE QUICK HEATER ASSEMBLY for LHD: REPLACE QUICK HEATER ASSEMBLY Click here
    REPLACE QUICK HEATER ASSEMBLY for RHD: REPLACE QUICK HEATER ASSEMBLY Click here