AIR CONDITIONING SYSTEM PTC Heater Circuit

DESCRIPTION

The air conditioning amplifier assembly sends operation signals to the PTC HTR relays when quick heater assembly (PTC heater) operation conditions are met. Based on the signals from the air conditioning amplifier assembly, the PTC HTR relays 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 mode switch (eco switch assembly) off

IDH terminal signal less than 1 V

(Inverter with converter assembly overload not detected)
Engine coolant temperature 70°C or lower
Ambient temperature 10°C or lower

WIRING DIAGRAM

A01I2QAE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. PERFORM ACTIVE TEST USING TECHSTREAM


    1. Connect the Techstream to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the Techstream 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.: 2 -
      OK
      Heater Active Level changes normally.

    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)


    1. A01I2TNE05

      Remove the PTC HTR NO. 1 relay and PTC HTR NO. 2 relay.

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

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

    NG

    REPLACE PTC HEATER RELAY

    OK

  3. CHECK HARNESS AND CONNECTOR (PTC HTR NO. 1 RELAY, PTC HTR NO. 2 RELAY - POWER SOURCE)


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

      Standard Voltage
      PTC1
      Tester Connection Condition Specified Condition
      3 - Body ground Power switch off 11 to 14 V
      2 - Body ground Power switch on (IG) 11 to 14 V
      PTC2
      Tester Connection Condition Specified Condition
      3 - Body ground Power switch off 11 to 14 V
      2 - Body ground Power switch on (IG) 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (PTC HTR NO. 1 RELAY, PTC HTR NO. 2 RELAY - AIR CONDITIONING AMPLIFIER ASSEMBLY)


    1. Disconnect the I77 air conditioning amplifier assembly connector.

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

      Standard Resistance
      PTC1
      Tester Connection Condition Specified Condition
      1 - I77-15 (PTC1) Always Below 1 Ω
      1 - Body ground Always 10 kΩ or higher
      PTC2
      Tester Connection Condition Specified Condition
      1 - I77-16 (PTC2) Always Below 1 Ω
      1 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (PTC HTR NO. 1 RELAY, PTC HTR NO. 2 RELAY - QUICK HEATER ASSEMBLY)


    1. Disconnect the I41 quick heater assembly connector.

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

      Standard Resistance
      PTC1
      Tester Connection Condition Specified Condition
      5 - I41-1 (B) Always Below 1 Ω
      5 - Body ground Always 10 kΩ or higher
      PTC2
      Tester Connection Condition Specified Condition
      5 - I41-2 (B) Always Below 1 Ω
      5 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT QUICK HEATER ASSEMBLY


    1. Remove the quick heater assembly Click here.

    2. A01I5EIE01
      Text in Illustration
      *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
      I41-1 (B)- a1-1 (B) Always Below 1 Ω
      I41-2 (B)- a1-1 (B) Always Below 1 Ω

    NG

    REPLACE QUICK HEATER ASSEMBLY Click here

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here