AIR CONDITIONING SYSTEM TERMINALS OF ECU


  1. CHECK PTC HEATER AMPLIFIER ASSEMBLY (w/ PTC Heater)

    A01KGC1E01

    1. Disconnect the P13 PTC heater amplifier connector.

    2. Measure the voltage and resistance of the wire harness side connector.

      Symbols (Terminal NO.) Wiring Color Terminal Description Condition Specified Condition
      IG (P13-1) - GND (P13-15) R-B - W-B Power source (IG) Ignition switch OFF Below 1 V
      IG (P13-1) - GND (P13-15) R-B - W-B Power source (IG) Ignition switch ON 11 to 14 V
      GND (P13-15) - Body ground W-B - Body ground Ground Always Below 1 Ω
      BLW (P13-2) - GND (P13-15) W - W-B Temperature control switch signal Temperature control knob: Max HOT Below 1 Ω
      BLW (P13-2) - GND (P13-15) W - W-B Temperature control switch signal Temperature control knob: except Max HOT 10 kΩ or higher
      HLS (P13-10) - GND (P13-15) R-W - W-B Light control switch signal Light control switch ON Below 1 V
      HLS (P13-10) - GND (P13-15) R-W - W-B Light control switch signal Light control switch OFF 11 to 14 V

      • If the result is not as specified, there may be a malfunction on the wire harness side.

    3. Reconnect the P13 PTC heater amplifier connector.

    4. Measure the voltage of the wire harness side connector.

      Symbols (Terminal NO.) Wiring Color Terminal Description Condition Specified Condition
      BLW (P13-2) - GND (P13-15) W - W-B Temperature control switch signal

      Ignition switch ON

      Temperature control knob: Max HOT

      Blower switch ON

      		 11 to 14 V
      BLW (P13-2) - GND (P13-15) W - W-B Temperature control switch signal

      Ignition switch ON

      Temperature control knob: except Max HOT

      Blower switch ON

      		 Below 1 V
      HEAT (P13-13) - GND (P13-15) Y-B - W-B Idle-up switch input signal

      Ignition switch ON

      Idle-up switch ON (momentary switch)

      		 Below 1 V
      HEAT (P13-13) - GND (P13-15) Y-B - W-B Idle-up switch input signal

      Ignition switch ON

      Idle-up switch OFF (momentary switch)

      		 11 to 14 V
      IND (P13-8) - GND (P13-15) W-L - W-B Heater switch indicator light signal

      Ignition switch ON

      Idle-up switch ON (momentary switch)

      		 11 to 14 V
      IND (P13-8) - GND (P13-15) W-L - W-B Heater switch indicator light signal

      Ignition switch ON

      Idle-up switch OFF (momentary switch)

      		 Below 1 V
      TW (P13-4) - GND (P13-15) R - W-B Water temperature signal Ignition switch ON Pulse generation
      TACO (P13-11) - GND (P13-15) B - W-B Tachometer signal Engine running

      Pulse generation

      (see waveform 1)
      ALT (P13-14) - GND (P13-15) L - W-B Generator Engine running Pulse generation
      PTC1 (P13-6) - GND (P13-15) L-W - W-B PTC heater relay signal

      Ignition switch ON

      Temperature control knob: Max HOT

      Blower switch ON

      Coolant temperature: 65°C (149°F) or lower

      Engine revolution: 650 rpm or more

      Generator: Generation signal output

      		 11 to 14 V
      PTC1 (P13-6) - GND (P13-15) L-W - W-B PTC heater relay signal

      Ignition switch ON

      Temperature control knob: except Max HOT

      Blower switch OFF

      Coolant temperature: 65°C (149°F) or lower

      		 Below 1 V
      PTC2 (P13-7) - GND (P13-15) W - W-B PTC heater relay signal

      Ignition switch ON

      Temperature control knob: Max HOT

      Blower switch ON

      Coolant temperature: 65°C (149°F) or lower

      Engine revolution: 650 rpm or more

      Generator: Generation signal output

      		 11 to 14 V
      PTC2 (P13-7) - GND (P13-15) W - W-B PTC heater relay signal

      Ignition switch ON

      Heater switch OFF

      Temperature control knob: except Max HOT

      Blower switch OFF

      Coolant temperature: 65°C (149°F) or lower

      		 Below 1 V
      PTCR (P13-5) - GND (P13-15) W-R - W-B Heater switch output signal for idle-up

      Ignition switch ON

      Blower switch ON

      Power heater switch ON

      Temperature control knob: Max HOT

      		 Below 1 V
      PTCR (P13-5) - GND (P13-15) W-R - W-B Heater switch output signal for idle-up

      Ignition switch ON

      Blower switch OFF

      Power heater switch OFF

      Temperature control knob: Max HOT

      		 11 to 14 V

      If the result is not as specified, the heater amplifier may have a malfunction.

    5. Inspect using an oscilloscope.


      1. A01KF8EE24

        Waveform 1

        Item Content
        Symbols (Terminal No.) TACO (P13-11) - GND (P13-15)
        Tool Setting 5 V/DIV., 20 msec./DIV.
        Condition Engine idling

        Tech Tips

        As engine speed increases, the wavelength shortens.

  2. CHECK ECM

    A01KFUOE57

    1. Measure the voltage of the connectors.


      1. 1KD-FTV

        w/ PTC heater
        Symbols (Terminal NO.) Wiring color Terminal Description Condition Specified Condition
        HSW (E8-16) - E01 (E6-7) W-R - BR Heater switch output signal for idle-up

        Ignition switch ON

        Blower switch ON

        Power heater switch ON

        Temperature control knob: Max HOT

        		 Below 1 V
        HSW (E8-16) - E01 (E6-7) W-R - BR Heater switch output signal for idle-up

        Ignition switch ON

        Blower switch OFF

        Power heater switch OFF

        Temperature control knob: Max HOT

        		 11 to 14 V
        THWO (E7-2) - E01 (E6-7)

        R -BR *1

        R-L -BR *2

        		 Engine coolant temperature signal Ignition switch ON Pulse generation
        TACH (E7-4) - E01 (E6-7) B - BR Tachometer signal Engine running

        Pulse generation

        (see waveform 1)

        *1: Europe

        *2: Singapore


        • If the result is not as specified, the ECM may have a malfunction.

    2. A01KF8EE25

      Inspect using an oscilloscope.


      1. Waveform 1

        Item Content
        Symbols (Terminal No.) TACH (E7-4) - E01 (E6-7)
        Tool Setting 5 V/DIV., 20 msec./DIV.
        Condition Engine idling

        Tech Tips

        As engine speed increases, the wavelength shortens.