AIR CONDITIONING SYSTEM > TERMINALS OF ECU

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

I100991E02

  1. Disconnect the A9 A/C 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+ (A9-10) - GND (A9-18)
    		R-L - L
    		Power source (IG)
    		Ignition switch OFF
    		Below 1 V
    IG+ (A9-10) - GND (A9-18)
    		R-L - L
    		Power source (IG)
    		Ignition switch ON
    		10 to 14 V
    GND (A9-18) - Body ground
    		L - Body ground
    		Ground
    		Always
    		Below 1 Ω
    ACON (A9-4) - GND (A9-18)
    		R-G - L
    		A/C switch signal
    		A/C switch OFF
    		Below 1 V
    ACON (A9-4) - GND (A9-18)
    		R-G - L
    		A/C switch signal
    		A/C switch ON
    		10 to 14 V
    IND- (A9-13) - GND (A9-18)
    		R-L - L
    		A/C indicator light signal
    		A/C switch OFF
    		Below 1 V
    IND- (A9-13) - GND (A9-18)
    		R-L - L
    		A/C indicator light signal
    		A/C switch ON
    		10 to 14 V

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

  3. Reconnect the A9 connector.

  4. Measure the voltage and resistance of the connector.

    Symbols (Terminal No.)
    		Wiring Color
    		Terminal Description
    		Condition
    		Specified Condition
    PSW (A9-3) - GND (A9-18)
    		Y-B - L
    		A/C pressure switch signal
    		Ignition switch START, refrigerant pressure normal, A/C switch ON, blower switch ON
    		10 to 14 V
    PSW (A9-3) - GND (A9-18)
    		Y-B - L
    		A/C pressure switch signal
    		Ignition switch START, refrigerant pressure less than 0.196 MPa (2.0 kgf/cm2, 28 psi) or more than 3.14 MPa (32.0 kgf/cm2, 455 psi), A/C switch ON, blower switch ON
    		Below 1 V
    TEfin (A9-7) - SG-1 (A9-18)
    		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
    TEfin (A9-7) - SG-1 (A9-18)
    		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 (A9-8) - Body ground
    		P - L
    		Ground for A/C evaporator temperature sensor
    		Always
    		Below 1 Ω
    MGC (A9-1) - GND (A9-18)
    		L-W - L
    		Magnet clutch signal
    		Ignition switch START, magnet clutch is not engaged
    		Below 1 V
    MGC (A9-1) - GND (A9-18)
    		L-W - L
    		Magnet clutch signal
    		Ignition switch START, magnet clutch is engaged
    		10 to 14 V
    ACT (A9-2) - GND (A9-18)
    		R-L - L
    		Magnet on permit signal
    		Ignition switch START, A/C switch OFF, blower switch ON
    		Below 1 V
    ACT (A9-2) - GND (A9-18)
    		R-L - L
    		Magnet on permit signal
    		Ignition switch START, A/C switch ON, blower switch ON
    		10 to 14 V
    AC1 (A9-14) - GND (A9-18)
    		Y - L
    		Idle-up request signal
    		Ignition switch START, magnet clutch is not engaged
    		10 to 14 V
    AC1 (A9-14) - GND (A9-18)
    		Y - L
    		Idle-up request signal
    		Ignition switch START, magnet clutch is engaged
    		Below 1 V

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


CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY (w/ PTC HEATER)

I100992E01

  1. Disconnect the A9 A/C 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 (A9-20) - GND (A9-29)
    		R-L - L
    		Power source (IG)
    		Ignition switch OFF
    		Below 1V
    IG (A9-20) - GND (A9-29)
    		R-L - L
    		Power source (IG)
    		Ignition switch ON
    		10 to 14 V
    GND (A9-29) - Body ground
    		L - Body ground
    		Ground
    		Always
    		Below 1 Ω
    ACON (A9-8) - GND (A9-29)
    		R-G - L
    		A/C switch signal
    		A/C switch OFF
    		Below 1 V
    ACON (A9-8) - GND (A9-29)
    		R-G - L
    		A/C switch signal
    		A/C switch ON
    		10 to 14 V
    IND- (A9-9) - GND (A9-29)
    		R-L - L
    		A/C indicator light signal
    		A/C switch OFF
    		Below 1 V
    IND- (A9-9) - GND (A9-29)
    		R-L - L
    		A/C indicator light signal
    		A/C switch ON
    		10 to 14 V
    BLW (MHOT) (A9-38) - GND (A9-29)
    		R-L - L
    		Max. HOT switch signal
    		Ignition switch ON, temperature control knob:
    Max. HOT
    		Below 1 Ω
    BLW (MHOT) (A9-38) - GND (A9-29)
    		R-L - L
    		Max. HOT switch signal
    		Ignition switch ON, temperature control knob:
    except Max. HOT
    		10 kΩ or higher
    POWHTR (A9-5) - GND (A9-29)
    		L-O - L
    		Heater switch signal
    		Heater switch ON
    		Below 1 Ω
    POWHTR (A9-5) - GND (A9-29)
    		L-O - L
    		Heater switch signal
    		Heater switch OFF
    		10 kΩ or higher
    MGC (A9-19) - GND (A9-29)
    		B - L
    		Magnet clutch relay signal
    		Ignition switch ON
    		10 to 14 V
    MGC (A9-19) - GND (A9-29)
    		B - L
    		Magnet clutch relay signal
    		Ignition switch OFF
    		Below 1 V
    TAIL (A9-7) - GND (A9-29)
    		G - L
    		Light control switch signal
    		Light control switch ON
    		10 to 14 V
    TAIL (A9-7) - GND (A9-29)
    		G - L
    		Light control switch signal
    		Light control switch OFF
    		Below 1 V

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

  3. Reconnect the A9 connector.

  4. Measure the voltage and resistance of the connector.

    Symbols (Terminal No.)
    		Wiring Color
    		Terminal Description
    		Condition
    		Specified Condition
    PSW (A9-4) - GND (A9-29)
    		Y-B - L
    		A/C pressure switch signal
    		Ignition switch START, refrigerant pressure normal, A/C switch ON, blower switch ON
    		10 to 14 V
    PSW (A9-4) - GND (A9-29)
    		Y-B - L
    		A/C pressure switch signal
    		Ignition switch START, refrigerant pressure less than 0.196 MPa (2.0 kgf/cm2, 28 psi) or more than 3.14 MPa (32.0 kgf/cm2, 455 psi), A/C switch ON, blower switch ON
    		Below 1 V
    TE (A9-24) - SG-1 (A9-31)
    		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 (A9-24) - SG-1 (A9-31)
    		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 (A9-31) - Body ground
    		P - L
    		Ground for A/C evaporator temperature sensor
    		Always
    		Below 1 Ω
    MGC (A9-19) - GND (A9-29)
    		B - L
    		Magnet clutch signal
    		Ignition switch START, magnet clutch is not engaged
    		Below 1 V
    MGC (A9-19) - GND (A9-29)
    		B - L
    		Magnet clutch signal
    		Ignition switch START, magnet clutch is engaged
    		10 to 14 V
    ACT (A9-39) - GND (A9-29)
    		R-L - L
    		Magnet on permit signal
    		Ignition switch START, A/C switch OFF, blower switch ON
    		Below 1 V
    ACT (A9-39) - GND (A9-29)
    		R-L - L
    		Magnet on permit signal
    		Ignition switch START, A/C switch ON, blower switch ON
    		10 to 14 V
    AC1 (A9-35) - GND (A9-29)
    		Y - L
    		Idle-up request signal
    		Ignition switch START, magnet clutch is not engaged
    		10 to 14 V
    AC1 (A9-35) - GND (A9-29)
    		Y - L
    		Idle-up request signal
    		Ignition switch START, magnet clutch is engaged
    		Below 1.0 V
    BLW (MHOT) (A9-38) - GND (A9-29)
    		R-L - L
    		Max. HOT switch signal
    		Ignition switch ON, temperature control knob:
    Max. HOT
    		10 to 14 V
    BLW (MHOT) (A9-38) - GND (A9-29)
    		R-L - L
    		Max. HOT switch signal
    		Ignition switch ON, temperature control knob:
    except Max. HOT
    		Below 1 V
    POWHTR (A9-5) - GND (A9-29)
    		L-O - L
    		Heater switch input signal
    		Heater switch ON
    		Below 1 V
    POWHTR (A9-5) - GND (A9-29)
    		L-O - L
    		Heater switch input signal
    		Heater switch OFF
    		10 to 14 V
    SWIN (HOTLP) (A9-15) - GND (A9-29)
    		P - L
    		Heater switch indicator light signal
    		Heater switch ON
    		Below 1 V
    SWIN (HOTLP) (A9-15) - GND (A9-29)
    		P - L
    		Heater switch indicator light signal
    		Heater switch OFF
    		10 to 14 V
    RPTC (A9-26) - GND (A9-29)
    		L-W - L
    		Heater switch output signal
    		Heater switch ON
    		10 to 14 V
    RPTC (A9-26) - GND (A9-29)
    		L-W - L
    		Heater switch output signal
    		Heater switch OFF
    		Below 1 V
    TW (A9-32) - GND (A9-29)
    		P - L
    		Water temperature signal
    		Ignition switch ON
    		Pulse generation
    TACO (A9-33) - GND (A9-29)
    		B-W - L
    		Tachometer signal
    		Engine running
    		Pulse generation
    (see waveform 1)
    ALT (A9-37) - GND (A9-29)
    		G - L
    		Generator
    		Ignition switch ON
    		9 to 14 V
    PTC1 (A9-3) - GND (A9-29)
    		R-W - L
    		PTC heater relay signal
    		Heater switch ON, temperature control knob: Max. HOT, coolant temperature: 55°C (131°F) or lower, blower switch LO
    		Below 1 V
    PTC1 (A9-3) - GND (A9-29)
    		R-W - L
    		PTC heater relay signal
    		Heater switch ON, temperature control knob: Max. HOT, coolant temperature: 55°C (131°F) or lower, blower switch OFF
    		10 to 14 V
    PTC2 (A9-2) - GND (A9-29)
    		GR - L
    		PTC heater relay signal
    		Heater switch ON, temperature control knob: Max. HOT, coolant temperature: 55°C (131°F) or lower, blower switch LO
    		Below 1 V
    PTC2 (A9-2) - GND (A9-29)
    		GR - L
    		PTC heater relay signal
    		Heater switch ON, temperature control knob: Max. HOT, coolant temperature: 55°C (131°F) or lower, blower switch OFF
    		10 to 14 V

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



    5. I042330E03

  5. Inspect using an oscilloscope.

    1. Waveform 1 (Reference)
      Item
      		Content
      Symbols (Terminal No.)
      		TACO (A9-33) - GND (A9-29)
      Tool Setting
      		5 V/DIV., 20 msec./DIV.
      Condition
      		Engine idling

      HINT:
      As engine speed increases, the wavelength shortens.


CHECK ECM

A066714E07

  1. Measure the voltage of the connectors.

    1. 1TR-FE, 2TR-FE

      Symbols (Terminal No.)
      		Wiring Color
      		Terminal Description
      		Condition
      		Specified Condition
      ACT (E10-25) - E01 (E12-7)
      		R-L - W-B
      		Magnet on permit signal
      		Ignition switch START, A/C switch OFF
      		Below 1 V
      ACT (E10-25) - E01 (E12-7)
      		R-L - W-B
      		Magnet on permit signal
      		Ignition switch START, A/C switch ON
      		10 to 14 V
      AC1 (E10-24) - E01 (E12-7)
      		Y - W-B
      		Idle-up request signal
      		Ignition switch START, A/C magnet clutch is engaged
      		Below 1.0 V
      AC1 (E10-24) - E01 (E12-7)
      		Y - W-B
      		Magnet on permit signal
      		Ignition switch START, A/C magnet clutch is not engaged
      		10 to 14 V

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

    2. 2KD-FTV

      Symbols (Terminal No.)
      		Wiring Color
      		Terminal Description
      		Condition
      		Specified Condition
      ACT (E6-19) - E01 (E8-7)
      		R-L - W-B
      		Magnet on permit signal
      		Ignition switch START, A/C switch OFF
      		Below 1 V
      ACT (E6-19) - E01 (E8-7)
      		R-L - W-B
      		Magnet on permit signal
      		Ignition switch START, A/C switch ON
      		10 to 14 V
      AC1 (E6-18) - E01 (E8-7)
      		Y - W-B
      		Idle-up request signal
      		Ignition switch START, magnet clutch is engaged
      		Below 1 V
      AC1 (E6-18) - E01 (E8-7)
      		Y - W-B
      		Magnet on permit signal
      		Ignition switch START, magnet clutch is not engaged
      		10 to 14 V
      THWO (E5-2) - E01 (E8-7)*
      		P - W-B
      		Water temperature signal
      		Ignition switch ON
      		Pulse generation
      HSW (E6-20) - E01 (E8-7)*
      		L-W - W-B
      		Heater switch output signal for idle-up
      		Heater switch ON
      		Below 1 V
      HSW (E6-20) - E01(E8-7)*
      		L-W - W-B
      		Heater switch output signal for idle-up
      		Heater switch OFF
      		10 to 14 V
      TACH (E5-4) - E01 (E8-7)*
      		B-W - W-B
      		Tachometer signal
      		Engine running
      		Pulse generation
      (see waveform 1)

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

        HINT:
        *: w/ PTC Heater



    2. I042330E03

  2. Inspect using an oscilloscope (w/ PTC heater only).

    1. Waveform 1 (Reference)
      Item
      		Content
      Symbols (Terminal No.)
      		TACH (E5-4) - E01 (E8-7)
      Tool Setting
      		5 V/DIV., 20 msec./DIV.
      Condition
      		Engine idling

      HINT:
      As engine speed increases, the wavelength shortens.