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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Heating / Air Conditioning System (Except HV, W/ Auto A/C) - Diagnostics - Introduction >> AIR CONDITIONING SYSTEM (for Gasoline Model with Automatic Air Conditioning System) >> Terminals Of Ecu [12/2019 - 10/2022] >> Terminals Of Ecu [12/2019 - 10/2022]

Terminals Of Ecu [12/2019 - 10/2022]

  1. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY 
    GTY850951Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    HINT: 

    Make sure to wait at least 2 minutes after turning the ignition switch off before performing an ECU terminal inspection.

    CHANNEL 1 (Z18)

    Terminal No.
    (Symbol)    		 Terminal Description Condition Specified Condition
    z18-2 (BUS G) - Body ground Ground for BUS IC Always Below 1 V
    z18-3 (BUS) - z18-2 (BUS G) BUS IC control signal Ignition switch ON Pulse generation
    (See waveform "Servo LIN communication")
    z18-4 (B BUS) - z18-2 (BUS G) Power supply for BUS IC Ignition switch off 11 to 14 V
    z18-5 (SG) - Body ground Ground for evaporator temp. sensor (No. 1 cooler thermistor) Always Below 1 V
    z18-6 (TE) - z18-5 (SG) Evaporator temp. sensor (No. 1 cooler thermistor) signal
    • Ignition switch ON
    • Evaporator temperature: 0°C (32°F)
    		 1.7 to 2.1 V
    • Ignition switch ON
    • Evaporator temperature: 15°C (59°F)
    		 0.9 to 1.3 V
    CHANNEL 2 (H62)

    Terminal No.
    (Symbol)    		 Terminal Description Condition Specified Condition
    H62-2 (CANH) - H62-1 (CANL) CAN communication system CAN communication is performed Pulse generation
    H62-5 (B) - H62-17 (GND) Power source (Back-up) Ignition switch off 11 to 14 V
    H62-6 (IG+) - H62-17 (GND) Power source (IG) Ignition switch ON 11 to 14 V
    Ignition switch off Below 1 V
    H62-7 (LIN1) - H62-17 (GND) LIN communication signal Ignition switch ON Pulse generation
    (See waveform "Control panel LIN communication")
    H62-17 (GND) - Body ground Ground for main power supply Always Below 1 V
    H62-18 (SOL+) - H62-17 (GND) Compressor solenoid operation signal
    • Engine running
    • Blower switch: LO
    • A/C switch: On
    		 Pulse generation
    (See waveform "Compressor solenoid")
    H62-21 (BLW) - H62-17 (GND) Blower motor speed control signal
    • Ignition switch ON
    • Blower switch: LO
    		 Pulse generation
    (See waveform "Blower")
    H62-23 (PTC1)* - H62-17 (GND) Quick heater assembly operation signal
    • Ignition switch ON
    • Temperature setting: MAX HOT
    • Ambient temperature: 10°C (50°F) or lower
    • Engine coolant temperature: 65°C (149°F) or lower
    • Light control switch off
    • Blower switch: On
    		 Below 1 V
    • Ignition switch ON
    • Temperature setting: MAX HOT
    • Ambient temperature: 10°C (50°F) or lower
    • Engine coolant temperature: 65°C (149°F) or lower
    • Light control switch off
    • Blower switch: Off
    		 11 to 14 V

    *: w/ Quick Heater

    CHANNEL 3 (H63)

    Terminal No.
    (Symbol)    		 Terminal Description Condition Specified Condition
    H63-1 (TAM) - H63-14 (SG-2) Ambient temp. sensor (thermistor assembly) signal
    • Ignition switch ON
    • Ambient temperature: 25°C (77°F)
    		 1.05 to 1.45 V
    • Ignition switch ON
    • Ambient temperature: 40°C (104°F)
    		 0.64 to 0.87 V
    H63-3 (SG-1) - Body ground Ground for room temp. sensor (cooler thermistor) Always Below 1 V
    H63-5 (TR) - H63-3 (SG-1) Room temp. sensor (cooler thermistor) signal
    • Ignition switch ON
    • Cabin temperature: 25°C (77°F)
    		 1.05 to 1.45 V
    • Ignition switch ON
    • Cabin temperature: 40°C (104°F)
    		 0.64 to 0.87 V
    H63-6 (PRE) - H63-15 (SG-4) Air conditioner pressure sensor signal
    • Engine start
    • Air conditioning system operating
    • Refrigerant pressure: Abnormal pressure (more than 2812 kPaG (28.7 kgf/cm2 , 408 psi))
    		 4.61 V or higher
    • Engine start
    • Air conditioning system operating
    • Refrigerant pressure: Abnormal pressure (less than 196 kPaG (2.0 kgf/cm2 , 28 psi))
    		 Below 0.74 V
    • Engine start
    • Air conditioning system operating
    • Refrigerant pressure: Normal pressure (less than 2812 kPaG (28.7 kgf/cm2 , 408 psi) and more than 196 kPaG (2.0 kgf/cm2 , 28 psi))
    		 0.74 to 4.61 V
    H63-11 (S5-3) - H63-15 (SG-4) Power supply for air conditioner pressure sensor Ignition switch ON 4.75 to 5.25 V
    Ignition switch off Below 1 V
    H63-12 (LOCK) - H63-14 (SG-2) A/C lock sensor signal
    • Engine running
    • Blower switch: LO
    • A/C switch: On
    		 Pulse generation
    (See waveform "A/C lock sensor")
    H63-14 (SG-2) - Body ground Ground for ambient temp. sensor (thermistor assembly) Always Below 1 V
    H63-15 (SG-4) - Body ground Ground for air conditioner pressure sensor Always Below 1 V
    H63-16 (PTC2)* - H62-17 (GND) Quick heater assembly operation signal
    • Ignition switch ON
    • Temperature setting: MAX HOT
    • Ambient temperature: 0°C (32°F) or lower
    • Engine coolant temperature: 62.5°C (144.5°F) or lower
    • Light control switch off
    • Blower switch: On
    		 Below 1 V
    • Ignition switch ON
    • Temperature setting: MAX HOT
    • Ambient temperature: 0°C (32°F) or lower
    • Engine coolant temperature: 62.5°C (144.5°F) or lower
    • Light control switch off
    • Blower switch: Off
    		 11 to 14 V
    H63-19 (MGC) - H62-17 (GND) Magnetic clutch operation signal
    • Engine running
    • Blower switch: LO
    • A/C switch: Off
    		 11 to 14 V
    • Engine running
    • Blower switch: LO
    • A/C switch: On
    		 Below 1 V

    *: w/ Quick Heater

    CHANNEL 4 (H64)

    Terminal No.
    (Symbol)    		 Terminal Description Condition Specified Condition
    H64-1 (+B2) - H62-17 (GND) Power source (Back-up) Ignition switch off 11 to 14 V
    H64-2 (RBBU) - H64-3 (RBUG) Power supply for BUS IC Ignition switch off 11 to 14 V
    H64-3 (RBUG) - Body ground Ground for BUS IC Always Below 1 V
    H64-4 (GND2) - Body ground Ground for main power supply Always Below 1 V
    H64-7 (RBUS) - H64-3 (RBUG) BUS IC control signal Ignition switch ON Pulse generation
    (See waveform "Servo LIN communication")
    H64-10 (SBLW) - H62-17 (GND) Blower motor speed control signal
    • Ignition switch ON
    • Blower switch: LO
    		 Pulse generation
    (See waveform "Blower")
    H64-20 (RLIN) - H62-17 (GND) LIN communication signal Ignition switch ON Pulse generation
    (See waveform "Control panel LIN communication")
    CHANNEL 5 (H65)

    Terminal No.
    (Symbol)    		 Terminal Description Condition Specified Condition
    H65-8 (TR) - H65-14 (SG-8) No. 2 room temp. sensor (cooler thermistor) signal
    • Ignition switch ON
    • Cabin temperature: 25°C (77°F)
    		 1.05 to 1.45 V
    • Ignition switch ON
    • Cabin temperature: 40°C (104°F)
    		 0.64 to 0.87 V
    H65-11 (TEC) - H65-15 (SG-9) Rear evaporator temp. sensor (No. 2 air conditioning harness assembly) signal
    • Ignition switch ON
    • Evaporator temperature: 0°C (32°F)
    		 1.7 to 2.1 V
    • Ignition switch ON
    • Evaporator temperature: 15°C (59°F)
    		 0.9 to 1.3 V
    H65-14 (SG-8) - Body ground Ground for No. 2 room temp. sensor (cooler thermistor) Always Below 1 V
    H65-15 (SG-9) - Body ground Ground for Rear evaporator temp. sensor (No. 2 air conditioning harness assembly) Always Below 1 V
    1. Waveform "Blower":
      GTY578346Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Item Content
      Terminal No.
      • H62-21 (BLW) - H62-17 (GND)
      • H64-10 (SBLW) - H62-17 (GND)
      Tool Setting 2 V/DIV., 1 ms./DIV.
      Condition
      • Ignition switch ON
      • Blower switch: LO
    2. Waveform "Control panel LIN communication":
      GTY600247Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Item Content
      Terminal No.
      • H62-7 (LIN1) - H62-17 (GND)
      • H64-20 (RLIN) - H62-17 (GND)
      Tool Setting 2 V/DIV., 20 ms./DIV.
      Condition Ignition switch ON
    3. Waveform "Servo LIN communication":
      GTY563288Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Item Content
      Terminal No.
      • z18-3 (BUS) - z18-2 (BUS G)
      • H64-7 (RBUS) - H64-3 (RBUG)
      Tool Setting 2 V/DIV., 2 ms./DIV.
      Condition Ignition switch ON
    4. Waveform "A/C lock sensor":
      GTY440187Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Item Content
      Terminal No. H63-12 (LOCK) - H63-14 (SG-2)
      Tool Setting 200 mV/DIV., 10 ms./DIV.
      Condition
      • Engine running
      • Blower switch: LO
      • A/C switch: On
    5. Waveform "Compressor solenoid":
      GTY443056Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Item Content
      Terminal No. H62-18 (SOL+) - H62-17 (GND)
      Tool Setting 5 V/DIV., 500 μs./DIV.
      Condition
      • Engine running
      • Blower switch: LO
      • A/C switch: On
  2. CHECK AIR CONDITIONING CONTROL ASSEMBLY (w/o Toyota Multi Operation Touch System) 
    GTY859621Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    HINT: 

    Check from the rear of the connector while it is connected to the air conditioning control assembly.

    Terminal No.
    (Symbol)    		 Terminal Description Condition Specified Condition
    H27-1 (ILL+) - Body ground Illumination signal Taillight off Below 1 V
    Taillight on 11 to 14 V
    H27-5 (ILL-) - Body ground Illumination signal Always Below 1 V
    H27-6 (IG+) - H27-10 (GND) Power source (IG) Ignition switch off Below 1 V
    Ignition switch ON 11 to 14 V
    H27-8 (LIN1) - Body ground LIN communication signal Ignition switch ON Pulse generation
    (See waveform)
    H27-10 (GND) - Body ground Ground for air conditioning control assembly Always Below 1 V
    1. Waveform:
      GTY563288Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Item Content
      Terminal No. H27-8 (LIN1) - Body ground
      Tool Setting 2 V/DIV., 20 ms./DIV.
      Condition Ignition switch ON
  3. CHECK AIR CONDITIONING CONTROL ASSEMBLY (w/ Toyota Multi Operation Touch System) 
    GTY859621Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    HINT: 

    Check from the rear of the connector while it is connected to the air conditioning control assembly.

    Terminal No.
    (Symbol)    		 Terminal Description Condition Specified Condition
    H27-3 (LIN1) - Body ground LIN communication signal Ignition switch ON Pulse generation
    (See waveform)
    H27-4 (IG+) - H27-8 (E) Power source (IG) Ignition switch off Below 1 V
    Ignition switch ON 11 to 14 V
    H27-5 (ILL+) - Body ground Illumination signal Taillight off Below 1 V
    Taillight on 11 to 14 V
    H27-8 (E) - Body ground Ground for air conditioning control assembly Always Below 1 V
    H27-10 (ILL-) - Body ground Illumination signal Always Below 1 V
    1. Waveform:
      GTY563288Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Item Content
      Terminal No. H27-3 (LIN1) - Body ground
      Tool Setting 2 V/DIV., 20 ms./DIV.
      Condition Ignition switch ON
  4. CHECK NO. 2 AIR CONDITIONING CONTROL ASSEMBLY 
    GTY879411Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    HINT: 

    Check from the rear of the connector while it is connected to the No. 2 air conditioning control assembly.

    Terminal No.
    (Symbol)    		 Terminal Description Condition Specified Condition
    T2-6 (ILL-) - Body ground Illumination signal Always Below 1 V
    T2-7 (E) - Body ground Ground for No. 2 air conditioning control assembly Always Below 1 V
    T2-8 (RLIN) - Body ground LIN communication signal Ignition switch ON Pulse generation
    (See waveform)
    T2-9 (IG) - T2-7 (E) Power source (IG) Ignition switch off Below 1 V
    Ignition switch ON 11 to 14 V
    T2-10 (ILL+) - Body ground Illumination signal Taillight off Below 1 V
    Taillight on 11 to 14 V
    1. Waveform:
      GTY563288Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Item Content
      Terminal No. T2-8 (RLIN) - Body ground
      Tool Setting 2 V/DIV., 20 ms./DIV.
      Condition Ignition switch ON
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