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


  1. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

    A01J6Q4E03

    1. Disconnect the A38 air conditioning amplifier assembly connector.

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

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      A38-1 (GND) - Body ground L - Body ground Ground Always Below 1 Ω
      A38-5 (+B1) - A38-1 (GND) L-Y - L Battery power source Always 11 to 14 V
      A38-6 (IG+) - A38-1 (GND) R-L - L IG power source Ignition switch off Below 1 V
      Ignition switch ON 11 to 14 V
      A38-13 (MGC) - Body ground B - Body ground Magnet clutch signal Ignition switch ON 11 to 14 V
      Ignition switch off Below 1 V
      A38-14 (HR) - Body ground L-W - Body ground HTR relay signal Ignition switch ON 11 to 14 V
      Ignition 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 A38 air conditioning amplifier assembly connector.

    4. Measure the voltage and resistance according to the value(s) in the table below.

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      A38-2 (BLW) - Body ground L-B - Body ground Blower motor speed control voltage

      • Ignition switch ON

      • Blower switch on (LO level)

      Pulse generation

      (See waveform 1)
      A38-3 (AOF) - A38-1 (GND) Y-B - L Mode damper servo operation voltage

      • Ignition switch ON

      • Mode switch DEF

      		 Below 1 V

      • Ignition switch ON

      • Mode switch FACE

      		 11 to 14 V
      A38-4 (AOD) - A38-1 (GND) R-B - L Mode damper servo operation voltage

      • Ignition switch ON

      • Mode switch FACE

      		 Below 1 V

      • Ignition switch ON

      • Mode switch DEF

      		 11 to 14 V
      A38-7 (ACT) - A38-1 (GND) R-L - L Magnet clutch on permit input signal

      • Engine idling

      • Blower switch on (LO level)

      • A/C switch off or on (magnet clutch off)

      		 Below 1 V

      • Engine idling

      • Blower switch on (LO level)

      • A/C switch on (magnet clutch on)

      		 11 to 14 V
      A38-8 (TW) - A38-1 (GND) P - L Engine coolant temperature sensor signal Ignition switch ON Pulse generation
      A38-9 (SPD) - Body ground V-W - Body ground Vehicle speed signal Driving at approximately 20 km/h (12 mph)

      Pulse generation

      (See waveform 2)
      A38-13 (MGC) - Body ground B - Body ground Magnet clutch signal

      • Engine idling

      • A/C switch on

      		 Below 1 V

      • Engine idling

      • A/C switch off

      		 11 to 14 V
      A38-17 (AMH) - A38-1 (GND) L - L Air mix damper servo operation signal

      • Ignition switch ON

      • Temperature switch MAX HOT

      		 11 to 14 V

      • Ignition switch ON

      • Temperature switch MAX COLD

      		 Below 1 V
      A38-18 (TAMO) - A38-1 (GND) P - L Ambient temperature signal Ignition switch ON Pulse generation
      A38-19 (AMC) - A38-1 (GND) R-W - L Air mix damper servo operation signal

      • Ignition switch ON

      • Temperature switch MAX HOT

      		 Below 1 V

      • Ignition switch ON

      • Temperature switch MAX COLD

      		 11 to 14 V
      A38-21 (AC1) - A38-1 (GND) Y - L Idle-up request signal

      • Engine idling

      • Blower switch on (LO level)

      • A/C switch off

      		 11 to 14 V

      • Engine idling

      • Blower switch on (LO level)

      • A/C switch on

      		 Below 1 V
      A38-22 (AIR) - A38-1 (GND) L-W - L Recirculation damper servo operation voltage

      • Ignition switch ON

      • Fresh switch on

      		 Below 1 V

      • Ignition switch ON

      • Recirculation switch on

      		 11 to 14 V
      A38-23 (AIF) - A38-1 (GND) G-Y - L Recirculation damper servo operation voltage

      • Ignition switch ON

      • Recirculation switch on

      		 Below 1 V

      • Ignition switch ON

      • Fresh switch on

      		 11 to 14 V
      A37-1 (TE) - A37-14 (SG-4) G - P No. 1 cooler thermistor signal

      • Ignition switch ON

      • Evaporator temperature 0°C (32°F)

      		 2 to 2.4 V

      • Ignition switch ON

      • Evaporator temperature 15°C (59°F)

      		 1.4 to 1.8 V
      A37-2 (S5-3) - A38-1 (GND) W-R - L Power supply for solar sensor Ignition switch ON 4.5 to 5.5 V
      A37-5 (PSW) - A38-1 (GND) Y-B - L Air conditioner pressure sensor signal

      • Engine idling

      • Refrigerant pressure normal

      		 Below 1 V

      • Engine idling

      • 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)

      		 11 to 14 V
      A37-7 (TS) - A37-2 (S5-3) L-W - W-R Solar sensor signal

      • Ignition switch ON

      • Solar sensor subjected to electric light

      • Vehicle indoors

      		 0.8 to 4.3 V

      • Ignition switch ON

      • Solar sensor covered with cloth

      • Vehicle indoors

      		 Below 0.8 V
      A37-9 (VER) - Body ground R - Body ground Steering wheel location information signal Always Below 1 Ω
      A37-11 (SG-2) - Body ground L-Y - Body ground Ground for pulse position sensor (Mode damper servo) Always Below 1 Ω
      A37-13 (SG-3) - Body ground BR-Y - Body ground Ground for cooler thermistor Always Below 1 Ω
      A37-14 (SG-4) - Body ground P - Body ground Ground for No. 1 cooler thermistor Always Below 1 Ω
      A37-16 (AGND) - A37-21 (AUXO) R-L - LG-R Input signal for pulse position sensor (recirculation damper servo)

      • Ignition switch ON

      • Air inlet control recirculation to fresh or vice versa

      		 Pulse generation
      A37-17 (PIA) - A37-21 (AUXO) P-B - LG-R Input signal for pulse position sensor (recirculation damper servo)

      • Ignition switch ON

      • Air inlet control recirculation to fresh or vice versa

      		 Pulse generation
      A37-18 (TR) - A37-13 (SG-3) GR - BR-Y Cooler thermistor signal

      • Ignition switch ON

      • Cabin temperature 25°C (77°F)

      		 1.8 to 2.2 V

      • Ignition switch ON

      • Cabin temperature 40°C (104°F)

      		 1.2 to 1.6 V
      A37-20 (SG-1) - Body ground BR-Y - Body ground Ground for pulse position sensor (air mix damper servo) Always Below 1 V
      A37-21 (AUXO) - Body ground LG-R - Body ground Ground for pulse position sensor (recirculation damper servo) Always Below 1 Ω
      A37-23 (PMB) - A37-20 (SG-1) W-L - BR-Y Input signal for pulse position sensor (air mix damper servo)

      • Ignition switch ON

      • Temperature switch MAX HOT to MAX COLD

      		 Pulse generation
      A37-24 (PMA) - A37-20 (SG-1) W-R - BR-Y Input signal for pulse position sensor (air mix damper servo)

      • Ignition switch ON

      • Temperature switch MAX COLD to MAX HOT

      		 Pulse generation
      A37-25 (POB) - A37-11(SG-2 ) LG - L-Y Input signal for pulse position sensor (mode damper servo)

      • Ignition switch ON

      • Mode control FACE to DEF or vice versa

      		 Pulse generation
      A37-26 (POA) - A37-11 (SG-2) L-O - L-Y Input signal for pulse position sensor (mode damper servo)

      • Ignition switch ON

      • Mode control FACE to DEF or vice versa

      		 Pulse generation

      • If the result is not as specified, the air conditioning amplifier assembly may have a malfunction.

    5. A01J3LRE03

      Using an oscilloscope, check waveform 1.

      Blower motor control signal
      Item Content
      Terminal No. (Symbol) A38-2 (BLW) - Body ground
      Tool Setting 1 V/DIV., 50 μsec./DIV.
      Condition Ignition switch ON, Blower switch on (LO level)

      Tech Tips

      When the blower level is increased, the duty ratio changes accordingly.

    6. A01J3A6E02

      Using an oscilloscope, check waveform 2.

      Vehicle speed signal
      Item Content
      Terminal No. (Symbol) A38-9 (SPD) - Body ground
      Tool Setting 5 V/DIV., 20 ms./DIV.
      Condition Driving at approximately 20 km/h (12 mph)

      Tech Tips

      As the vehicle speed increases, the wavelength becomes shorter.

  2. CHECK ECM (for 2TR-FE)

    A01J4ZLE10

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

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      E9-14 (THWO) - E11-3 (E1) P - BR Engine coolant temperature output signal Engine idling Pulse generation
      E9-24 (AC1) - E11-3 (E1) Y - BR Idle-up request signal

      • Engine idling

      • Blower switch on (LO level)

      • A/C switch on

      		 Below 1 V

      • Engine idling

      • Blower switch on (LO level)

      • A/C switch off

      		 11 to 14 V
      E9-25 (ACT) - E11-3 (E1) R-L - BR Magnet clutch on permit output signal

      • Engine idling

      • Blower switch on (LO level)

      • A/C switch off or on (magnet clutch on)

      		 Below 1 V

      • Engine idling

      • Blower switch on (LO level)

      • A/C switch on (magnet clutch on)

      		 11 to 14 V

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

  3. CHECK ECM (for 1GR-FE)

    A01J6TME01

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

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      E13-14 (THWO) - E17-1 (E1) P - BR Engine coolant temperature output signal Engine idling Pulse generation
      E13-24 (AC1) - E17-1 (E1) Y - BR Idle-up request signal

      • Engine idling

      • Blower switch on (LO level)

      • A/C switch on

      		 Below 1 V

      • Engine idling

      • Blower switch on (LO level)

      • A/C switch off

      		 11 to 14 V
      E13-25 (ACT) - E17-1 (E1) R-L - BR Magnet clutch on permit output signal

      • Engine idling

      • Blower switch on (LO level)

      • A/C switch off or on (magnet clutch on)

      		 Below 1 V

      • Engine idling

      • Blower switch on (LO level)

      • A/C switch on (magnet clutch on)

      		 11 to 14 V

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

  4. CHECK ACCESSORY METER ASSEMBLY

    A01J731E06

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

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      A43-3 (TH+) - A43-2 (SG) W-G - BR-Y Ambient temperature sensor signal

      • Ignition switch ON

      • Ambient temperature 20 to 30°C (68 to 86°F)

      		 1 to 1.6 V
      Ambient temperature sensor signal

      • Ignition switch ON

      • Ambient temperature 30 to 50°C (86 to 122°F)

      		 0.6 to 1 V
      A43-9 (DATA) - A43-1 (GND1) P - LG Ambient temperature sensor signal Ignition switch ON Pulse generation

      • If the result is not as specified, the accessory meter assembly may have a malfunction.

  5. CHECK COMBINATION METER ASSEMBLY

    A01J30RE04

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

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      C27-6 - C27-22 V-R - Y Vehicle speed signal Driving at approximately 20 km/h (12 mph)

      Pulse generation

      (See waveform)

      • If the result is not as specified, the combination meter assembly may have a malfunction.

    2. A01J3A6E02

      Using an oscilloscope, check waveform 1.

      Vehicle speed signal
      Item Content
      Terminal No. (Symbol) C27-6 - C27-22
      Tool Setting 5 V/DIV., 20 ms./DIV.
      Condition Driving at approximately 20 km/h (12 mph)

      Tech Tips

      When the blower level is increased, the duty ratio changes accordingly.