AIR CONDITIONING SYSTEM (for Manual Air Conditioning System) TERMINALS OF ECU


  1. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY (w/o PTC HEATER)

    A01J7NSE04

    1. Disconnect the A14 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+ (A14-10) - GND (A14-18) R-L - L Power source (IG) Ignition switch OFF Below 1 V
      IG+ (A14-10) - GND (A14-18) R-L - L Power source (IG) Ignition switch ON 10 to 14 V
      GND (A14-18) - Body ground L - Body ground Ground Always Below 1 Ω
      ACON (A14-4) - GND (A14-18) R-G - L A/C switch signal

      Ignition switch START

      Blower switch ON

      A/C switch OFF

      		 Below 1 V
      ACON (A14-4) - GND (A14-18) R-G - L A/C switch signal

      Ignition switch START

      Blower switch ON

      A/C switch ON

      		 10 to 14 V
      IND- (A14-13) - GND (A14-18) R-L - L A/C indicator light signal

      Ignition switch START

      Blower switch ON

      A/C switch OFF

      		 Below 1 V
      IND- (A14-13) - GND (A14-18) R-L - L A/C indicator light signal

      Ignition switch START

      Blower switch ON

      A/C switch ON

      		 10 to 14 V

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

    3. Reconnect the A14 amplifier connector.

    4. Measure the voltage and resistance of the connector.

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      PSW (A14-3) - GND (A14-18) Y-B - L A/C pressure switch signal

      Ignition switch START

      Refrigerant pressure normal: 0.18 MPa (1.9 kgf/cm2, 26 psi) to 3.03 MPa (31.0 kgf/cm2, 440 psi)

      A/C switch ON

      Blower switch ON

      		 10 to 14 V
      PSW (A14-3) - GND (A14-18) Y-B - L A/C pressure switch signal

      Ignition switch START

      Refrigerant pressure less than 0.18 MPa (1.9 kgf/cm2, 26 psi) or more than 3.03 MPa (31.0 kgf/cm2, 440 psi)

      A/C switch ON

      Blower switch ON

      		 Below 1 V
      TE (A14-7) - SG-1 (A14-8) G - P A/C evaporator temperature sensor signal

      Ignition switch ON

      Evaporator temperature is 0°C (32°F)

      Temperature control knob: Max COOL

      		 2.0 to 2.4 V
      TE (A14-7) - SG-1 (A14-8) G - P A/C evaporator temperature sensor signal

      Ignition switch ON

      Evaporator temperature is 15°C (59°F)

      Temperature control knob: Max COOL

      		 1.4 to 1.8 V
      SG-1 (A14-8) - Body ground P - L Ground for A/C evaporator temperature sensor Always Below 1 Ω
      MGC (A14-1) - GND (A14-18) L-W - L Magnet clutch signal

      Ignition switch START

      Magnet clutch is not engaged

      		 Below 1 V
      MGC (A14-1) - GND (A14-18) L-W - L Magnet clutch signal

      Ignition switch START

      Magnet clutch is engaged

      		 10 to 14 V
      ACT (A14-2) - GND (A14-18) R-L - L Magnet on permit signal

      Ignition switch START

      A/C switch OFF

      Blower switch ON

      		 Below 1 V
      ACT (A14-2) - GND (A14-18) R-L - L Magnet on permit signal

      Ignition switch START

      A/C switch ON

      Blower switch ON

      		 10 to 14 V
      AC1 (A14-14) - GND (A14-18) Y - L Idle-up request signal

      Ignition switch START

      Magnet clutch is not engaged

      		 10 to 14 V
      AC1 (A14-14) - GND (A14-18) Y - L Idle-up request signal

      Ignition switch START

      Magnet clutch is engaged

      		 Below 1 V

      • If the result is not as specified, the A/C amplifier may have a malfunction.

  2. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY (w/ PTC HEATER)

    A01J6P6E05

    1. Disconnect the A33 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+ (A33-20) - GND (A33-29) R-L - L Power source (IG) Ignition switch OFF Below 1V
      IG (A33-20) - GND (A33-29) R-L - L Power source (IG) Ignition switch ON 10 to 14 V
      GND (A33-29) - Body ground L - Body ground Ground Always Below 1 Ω
      ACON (A33-8) - GND (A33-29) R-G - L A/C switch signal

      Ignition switch ON

      Blower switch OFF

      A/C switch OFF

      		 Below 1 V
      ACON (A33-8) - GND (A33-29) R-G - L A/C switch signal

      Ignition switch ON

      Blower switch ON

      A/C switch ON

      		 10 to 14 V
      IND- (A33-9) - GND (A33-29) R-L - L A/C indicator light signal

      Ignition switch ON

      Blower switch OFF

      A/C switch OFF

      		 Below 1 V
      IND- (A33-9) - GND (A33-29) R-L - L A/C indicator light signal

      Ignition switch ON

      Blower switch ON

      A/C switch ON

      		 10 to 14 V
      BLW (MHOT) (A33-38) - GND (A33-29) R-L - L Max. HOT switch signal

      Ignition switch ON

      Temperature control knob: Max HOT

      		 Below 1 Ω
      BLW (MHOT) (A33-38) - GND (A33-29) R-L - L Max. HOT switch signal

      Ignition switch ON

      Temperature control knob: except Max HOT

      		 10 kΩ or higher
      POWHTR (A33-5) - GND (A33-29) L-O - L Heater switch signal Power heater switch ON Below 1 Ω
      POWHTR (A33-5) - GND (A33-29) L-O - L Heater switch signal Power heater switch OFF 10 kΩ or higher
      MGC (A33-19) - GND (A33-29) B - L Magnet clutch relay signal

      Ignition switch ON

      Blower switch ON

      		 10 to 14 V
      MGC (A33-19) - GND (A33-29) B - L Magnet clutch relay signal

      Ignition switch ON

      Blower switch OFF

      		 Below 1 V
      TAIL (A14-7) - GND (A14-29) G - L Light control switch signal Light control switch ON 10 to 14 V
      TAIL (A33-7) - GND (A33-29) G - L Light control switch signal Light control switch OFF Below 1 V

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

    3. Reconnect the A33 connector.

    4. Measure the voltage and resistance of the connector.

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      PSW (A33-4) - GND (A33-29) Y-B - L A/C pressure switch signal

      Ignition switch START

      Refrigerant pressure normal: 0.18 MPa (1.9 kgf/cm2, 26 psi) to 3.03 MPa (31.0 kgf/cm2, 440 psi)

      A/C switch ON

      Blower switch ON

      		 10 to 14 V
      PSW (A33-4) - GND (A33-29) Y-B - L A/C pressure switch signal

      Ignition switch START

      Refrigerant pressure less than 0.18 MPa (1.9 kgf/cm2, 26 psi) or more than 3.03 MPa (31.0 kgf/cm2, 440 psi)

      A/C switch ON

      Blower switch ON

      		 Below 1 V
      TE (A33-24) - SG-1 (A33-31) G - P Evaporator temperature sensor signal

      Ignition switch ON

      Evaporator temperature is 0°C (32°F)

      Temperature control knob: MAX COOL

      		 2.0 to 2.4 V
      TE (A33-24) - SG-1 (A33-31) G - P Evaporator temperature sensor signal

      Ignition switch ON

      Evaporator temperature is 15°C (59°F)

      Temperature control knob: MAX COOL

      		 1.4 to 1.8 V
      SG-1 (A33-31) - Body ground P - L Ground for evaporator temperature sensor Always Below 1 Ω
      MGC (A33-19) - GND (A33-29) B - L Magnet clutch signal

      Ignition switch START

      Magnet clutch is not engaged

      		 Below 1 V
      MGC (A33-19) - GND (A33-29) B - L Magnet clutch signal

      Ignition switch START

      Magnet clutch is engaged

      		 10 to 14 V
      ACT (A33-39) - GND (A33-29) R-L - L Magnet on permit signal

      Ignition switch START

      A/C switch OFF

      Blower switch OFF

      		 Below 1 V
      ACT (A33-39) - GND (A33-29) R-L - L Magnet on permit signal

      Ignition switch START

      A/C switch ON

      Blower switch ON

      		 10 to 14 V
      AC1 (A33-35) - GND (A33-29) Y - L Idle-up request signal

      Ignition switch START

      Magnet clutch is not engaged

      		 10 to 14 V
      AC1 (A33-35) - GND (A33-29) Y - L Idle-up request signal

      Ignition switch START

      Magnet clutch is engaged

      		 Below 1.0 V
      BLW (A33-38) - GND (A33-29) R-L - L Max. HOT switch signal

      Ignition switch ON

      Blower switch ON

      temperature control knob: Max HOT

      Heater switch ON

      Coolant temperature 65°C (149°F)

      		 10 to 14 V
      BLW (A33-38) - GND (A33-29) R-L - L Max. HOT switch signal

      Ignition switch ON

      Blower switch ON

      Temperature control knob: except Max HOT

      Heater switch OFF

      Coolant temperature 65°C (149°F)

      		 Below 1 V
      HEAT (A33-5) - GND (A33-29) L-O - L Heater switch input signal

      Ignition switch ON

      Blower switch ON

      temperature control knob: Max HOT

      Heater switch ON

      Coolant temperature 65°C (149°F)

      		 Below 1 V
      HEAT (A33-5) - GND (A33-29) L-O - L Heater switch input signal

      Ignition switch ON

      Blower switch ON

      Temperature control knob: except Max HOT

      Heater switch OFF

      Coolant temperature 65°C (149°F)

      		 10 to 14 V
      SWIN (A33-15) - GND (A33-29) P - L Heater switch indicator light signal

      Ignition switch ON

      Blower switch ON

      temperature control knob: Max HOT

      Heater switch ON

      Coolant temperature 65°C (149°F)

      		 Below 1 V
      SWIN (A33-15) - GND (A33-29) P - L Heater switch indicator light signal

      Ignition switch ON

      Blower switch ON

      Temperature control knob: except Max HOT

      Heater switch OFF

      Coolant temperature 65°C (149°F)

      		 10 to 14 V
      PTCR (A33-26) - GND (A33-29) L-W - L Heater switch output signal

      Ignition switch ON

      Blower switch ON

      temperature control knob: Max HOT

      Heater switch ON

      Coolant temperature 65°C (149°F)

      		 10 to 14 V
      PTCR (A33-26) - GND (A33-29) L-W - L Heater switch output signal

      Ignition switch ON

      Blower switch ON

      Temperature control knob: except Max HOT

      Heater switch OFF

      Coolant temperature 65°C (149°F)

      		 Below 1 V
      TW (A33-32) - GND (A33-29) P - L Engine coolant temperature signal Ignition switch ON Pulse generation
      TACO (A33-33) - GND (A33-29) B-W - L Tachometer signal Engine running

      Pulse generation

      (see waveform 1)
      ALT (A33-37) - GND (A33-29) G - L Generator signal Engine running Pulse generation
      PTC1 (A33-3) - GND (A33-29) R-W - L PTC heater relay signal

      Ignition switch ON

      Blower switch ON

      temperature control knob: Max HOT

      Heater switch ON

      Coolant temperature 65°C (149°F)

      		 Below 1 V
      PTC1 (A33-3) - GND (A33-29) R-W - L PTC heater relay signal

      Ignition switch ON

      Blower switch ON

      Temperature control knob: except Max HOT

      Heater switch OFF

      Coolant temperature 65°C (149°F)

      		 10 to 14 V
      PTC2 (A33-2) - GND (A33-29) GR - L PTC heater relay signal

      Ignition switch ON

      Blower switch ON

      temperature control knob: Max HOT

      Heater switch ON

      Coolant temperature 65°C (149°F)

      		 Below 1 V
      PTC2 (A33-2) - GND (A33-29) GR - L PTC heater relay signal

      Ignition switch ON

      Blower switch ON

      Temperature control knob: except Max HOT

      Heater switch OFF

      Coolant temperature 65°C (149°F)

      		 10 to 14 V

      • If the result is not as specified, the A/C amplifier may have a malfunction.

    5. A01J3KJE03

      Inspect using an oscilloscope.


      1. Waveform 1 (Reference)

        Item Content
        Symbols (Terminal No.) TACO (A33-33) - GND (A33-29)
        Tool Setting 5 V/DIV., 20 msec./DIV.
        Condition Engine idling

        Tech Tips

        As engine speed increases, the wavelength shortens.

  3. CHECK ECM (for 1GR-FE)

    A01J38DE05

    1. Measure the voltage of the connectors.

      Tech Tips

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      ACT (E13-25) - E01 (E15-7) R-L - W-B Magnet on permit signal

      Ignition switch START

      A/C switch OFF

      Blower switch OFF

      		 Below 1 V
      ACT (E13-25) - E01 (E15-7) R-L - W-B Magnet on permit signal

      Ignition switch START

      A/C switch ON

      Blower switch ON

      		 10 to 14 V
      AC1 (E13-24) - E01 (E15-7) Y - W-B Idle-up request signal

      Ignition switch START

      A/C magnet clutch is engaged

      		 Below 1 V
      AC1 (E13-24) - E01 (E15-7) Y - W-B Magnet on permit signal

      Ignition switch START

      A/C magnet clutch is not engaged

      		 10 to 14 V

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

  4. CHECK ECM (for 2TR-FE)

    A01J3W7E03

    1. Measure the voltage of the connectors.

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      ACT (E9-25) - E01 (E11-6) R-L - W-B Magnet on permit signal

      Ignition switch START

      A/C switch OFF

      Blower switch OFF

      		 Below 1 V
      ACT (E9-25) - E01 (E11-6) R-L - W-B Magnet on permit signal

      Ignition switch START

      A/C switch ON

      Blower switch ON

      		 10 to 14 V
      AC1 (E9-24) - E01 (E11-6) Y - W-B Idle-up request signal

      Ignition switch START

      A/C magnet clutch is engaged

      		 Below 1 V
      AC1 (E9-24) - E01 (E11-6) Y - W-B Magnet on permit signal

      Ignition switch START

      A/C magnet clutch is not engaged

      		 10 to 14 V

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

  5. CHECK ECM (for 1KD-FTV)

    A01J71RE12

    1. Measure the voltage of the connectors.

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      ACT (E5-19) - E01 (E7-7) R-L - W-B Magnet on permit signal

      Ignition switch START

      A/C switch OFF

      Blower switch OFF

      		 Below 1 V
      ACT (E5-19) - E01 (E7-7) R-L - W-B Magnet on permit signal

      Ignition switch START

      A/C switch ON

      Blower switch ON

      		 10 to 14 V
      AC1 (E5-18) - E01 (E7-7) Y - W-B Idle-up request signal

      Ignition switch START

      A/C magnet clutch is engaged

      		 Below 1 V
      AC1 (E5-18) - E01 (E7-7) Y - W-B Magnet on permit signal

      Ignition switch START

      A/C magnet clutch is not engaged

      		 10 to 14 V
      THWO (E4-2) - E01 (E7-7)* P - W-B Water temperature signal Ignition switch START Pulse generation
      HSW (E4-20) - E01 (E7-7)* L-W - W-B Heater switch output signal for idle-up

      Ignition switch START

      Heater switch ON

      Blower switch ON

      Temperature control knob: Max HOT

      Engine coolant temperature 65°C (149 °F)

      		 Below 1 V
      HSW (E4-20) - E01(E7-7)* L-W - W-B Heater switch output signal for idle-up

      Ignition switch START

      Heater switch OFF

      Blower switch ON

      Temperature control knob: except Max HOT

      Engine coolant temperature 65°C (149 °F)

      		 10 to 14 V
      TACH (E4-4) - E01 (E7-7)* B-W - W-B Tachometer signal Engine running

      Pulse generation

      (see waveform 1)

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

      Tech Tips

      *: w/ PTC Heater

    2. A01J3KJE03

      Inspect using an oscilloscope (w/PTC heater only)


      1. Waveform 1 (Reference)

        Item Content
        Symbols (Terminal No.) TACH (E4-4) - E01 (E7-7)
        Tool Setting 5 V/DIV., 20 msec./DIV.
        Condition Engine idling

        Tech Tips

        As engine speed increases, the wavelength shortens.