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


  1. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

    B001YP9E03

    1. Disconnect the E81 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
      E81-21 (+B1) - E81-14 (GND) R - W-B Battery power source Always 11 to 14 V
      E81-1 (IG+) - E81-14 (GND) G - W-B Ignition power supply Ignition switch ON 11 to 14 V
      Ignition switch off Below 1 V
      E81-14 (GND) - Body ground W-B - Body ground Ground Always Below 1 Ω

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

    3. Reconnect the E81 air conditioning amplifier assembly connector.

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

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      E81-8 (LOCK) - E81-35 (SG-5) L - G Compressor lock sensor signal

      Engine idling

      Blower switch LO level

      A/C switch on (magnet clutch on)

      Pulse generation

      (see waveform 1)
      E81-35 (SG-5) - Body ground G - Body ground Ground for compressor lock sensor signal Always Below 1 Ω
      E81-13 (SG-2) - Body ground G - Body ground Ground for pressure sensor Always Below 1 Ω
      E81-17 (AC1) - Body ground L - Body ground Air conditioning operation request signal

      Engine idling

      Blower switch LO level

      A/C switch off

      		 11 to 14 V

      Engine idling

      Blower switch LO level

      A/C switch on

      		 Below 1 V
      E81-27 (ACT) - Body ground G - Body ground Magnet clutch operation permission signal

      Engine idling

      Blower switch LO level

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

      		 11 to 14 V

      Engine idling

      Blower switch LO level

      A/C switch on (magnet clutch on)

      		 Below 1 V
      E81-5 (TAM) - E81-13 (SG-2) V - G Ambient temperature sensor signal

      Ignition switch ON

      Ambient temperature 25°C (77°F)

      		 1.6 to 1.8 V

      Ignition switch ON

      Ambient temperature 50°C (122°F)

      		 0.5 to 0.7 V
      E81-30 (S5-1) - E81-13 (SG-2) LG - G Power supply for pressure sensor Ignition switch ON 4.5 to 5.5 V
      E81-9 (PRE) - E81-13 (SG-2) R - G Air conditioning pressure sensor signal

      Engine idling

      Blower switch LO level

      A/C switch on

      		 0.63 to 4.72 V

      Engine idling

      Blower switch LO level

      A/C switch off

      		 0.63 to 4.72 V
      E81-20 (MGC) - E81-14 (GND) R - W-B Magnet clutch operation signal

      Engine idling

      Blower switch LO level

      A/C switch on (magnet clutch on permitted)

      		 Below 1 V

      Engine idling

      Blower switch LO level

      A/C switch off or on (magnet clutch on not permitted)

      		 11 to 14 V
      E81-23 (BLW) - E81-14 (GND) R - W-B Blower motor control signal

      Ignition switch ON

      Blower switch LO level

      Pulse generation

      (see waveform 2)
      E81-37 (LIN1) - E81-14 (GND) Y - W-B LIN communication signal Ignition switch ON Pulse generation
      E81-25 (ALT) - Body ground R - Body ground Generator signal Engine idling Pulse generation
      E81-3 (PTC1) - Body ground* W - Body ground PTC heater relay operation signal

      Engine idling

      Set temperature MAX. HOT

      Engine coolant temperature below 65°C (149°F)

      Ambient temperature below 10°C (50°F)

      Blower switch off → LO level

      		 Below 1 V → 11 to 14 V
      E81-22 (PTC2) - Body ground* R - Body ground
      E81-4 (PTC3) - Body ground* R - Body ground
      z54-4 (B BUS) - z54-2 (BUS G) - Power supply for BUS IC Ignition switch ON 11 to 14 V
      z54-5 (SGA) - Body ground - Ground for No. 1 cooler thermistor Always Below 1 Ω
      z54-2 (BUS G) - Body ground - Ground for BUS IC Always Below 1 Ω
      z54-6 (TEA) - z54-5 (SGA) - No. 1 cooler thermistor signal

      Ignition switch ON

      Evaporator temperature 15°C (59°F)

      		 1.4 to 1.8 V
      z54-3 (BUS) - z54-2 (BUS G) - BUS IC control signal Ignition switch ON Pulse generation

      • *: w/ PTC Heater


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

    5. B001WNQE05

      Using an oscilloscope, check waveform 1.

      Compressor Lock Sensor Signal
      Item Content
      Terminal No. (Symbol) E81-8 (LOCK) - E81-35 (SG-5)
      Tool Setting 200 mV/DIV., 10 ms/DIV.
      Condition

      Engine idling

      Blower switch LO level

      A/C switch on (magnet clutch on)

      Tech Tips

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

    6. B001YRCE55

      Using an oscilloscope, check waveform 2.

      Blower Motor Control Signal
      Item Content
      Terminal No. (Symbol) E81-23 (BLW) - E81-14 (GND)
      Tool Setting 1 V/DIV., 500 μs/DIV.
      Condition

      Ignition switch ON

      Blower switch LO level

      Tech Tips

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

  2. CHECK AIR CONDITIONING CONTROL ASSEMBLY

    B001VQYE05

    1. Disconnect the F10 air conditioning control assembly connector.

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

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      F10-7 (IG+) - F10-1 (GND) G - W-B Ignition power supply Ignition switch ON 11 to 14 V
      Ignition switch off Below 1 V
      F10-1 (GND) - Body ground W-B - Body ground Ground Always Below 1 Ω

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