2012 Toyota Avalon BaseFACTORY OEM SERVICE PROCEDURE

Terminals Of Ecu

  1. CHECK POWER SOURCE CONTROL ECU 
    Fig 1: Power Source Control ECU Connector Terminal Identification
    GTY195503Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the D44 ECU connector.
    2. Measure the resistance and voltage of the wire harness side connector.

      Standard

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      AM1 (D44-33) - Body ground W - Body ground +B power supply Always 10 to 14 V
      AM2 (D44-12) - Body ground L - Body ground +B power supply Always 10 to 14 V
      SSW1 (D44-14) - Body ground P - Body ground Engine switch signal Engine switch pushed → Not pushed Below 1 Ω → 10 kΩ or higher
      SSW2 (D44-37) - Body ground V - Body ground Engine switch signal Engine switch pushed → Not pushed Below 1 Ω → 10 kΩ or higher
      GND2 (D44-6) - Body ground W-B - Body ground Ground Always Below 1 Ω
      MPX1 (D44-7) - Body ground V - Body ground MPX line Always 10 kΩ or higher
      MPX2 (D44-24) - Body ground LG - Body ground MPX line Always 10 kΩ or higher
      LIN1 (D44-30) - Body ground BR - Body ground LIN line Always 10 kΩ or higher

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

    3. Reconnect the D44 ECU connector.
    4. Measure the voltage of the connector.

      Standard voltage

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      ACCD (D44-11) - GND2 (D44-6) R - W-B ACC signal Engine switch OFF → Engine switch ON (ACC) Below 1 V → 10 to 14 V
      IG1D (D44-34) - GND2 (D44-6) LG - W-B IG1 signal Engine switch ON(ACC) → Engine switch ON (IG) Below 1 V → 10 to 14 V
      IG2D (D44-35) - GND2 (D44-6) Y - W-B IG2 signal Engine switch ON(ACC) → Engine switch ON (IG) Below 1 V → 10 to 14 V
      STP (D44-1) - GND2 (D44-6) LG - W-B Stop light signal Brake pedal depressed → Released 10 to 14 V → Below 1 V
      SLR+ (D44-32) - GND2 (D44-6) P - W-B Power source for steering lock actuator Steering lock motor operate → not operate Below 1 V → 10 to 14 V
      SLP (D44-26) - GND2 (D44-6) BE - W-B Steering lock actuator UNLOCK position signal Steering is locked → released 10 to 14 V → Below 1 V
      SPD (D44-19) - GND2 (D44-6) W - W-B Vehicle speed signal Engine switch ON (IG), Rotate driving wheel slowly Pulse generation
      TACH (D44-2) - Body ground L - Body ground Engine revolution speed signal Idling Pulse generation (see waveform 1 found in Fig 2)
      P (D44-5) - Body ground P - Body ground Shift lock signal Shift lever P position → D position Below 1 V → 10 to 14 V
      CTSW (D44-31) - Body ground BE - Body ground Starter assist signal Brake pedal depressed, Engine switch ON (START) (*1) Below 1 V
      STSW (D44-39) - Body ground R - Body ground Starter activation request signal Brake pedal depressed, Engine switch ON (START) (*2) 10 to 14 V
      STR1 (D44-17) - GND2 (D44-6) B - W-B Park / neutral position switch Shift lever P or N position, Engine switch ON (START) 10 to 14 V
      STR2 (D44-15) - GND2 (D44-6) SB - W-B Starter signal Shift lever P or N position, Engine switch ON (START) 10 to 14 V
      INDS (D44-4) - Body ground Y - Body ground Vehicle condition signal Brake pedal depressed, Shift lever P or N position, Engine switch ON (ACC, IG, START) 10 to 14 V
      INDW (D44-13) - Body ground GR - Body ground Warning signal Smart key system malfunction Pulse generation
      SWIL (D44-36) - Body ground G - Body ground Illumination signal Light control switch TAIL or HEAD 10 to 14 V

      *1: Voltage is output only when the engine is cranking.

      *2: Voltage is output for 0.3 seconds after engine start.

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

      1. WAVEFORM 1
        Fig 2: Identifying Signal Waveform 1
        GTY184256Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Engine speed signal

        ECM Terminal Names Between TACH and E1
        Tester Ranges 5V/DIV, 10 msec./DIV
        Conditions Idling

        HINT: 

        The wavelength becomes shorter as the engine rpm increases.

  2. CHECK CERTIFICATION ECU 
    Fig 3: Certification ECU Connector Terminal Identification
    GTY192340Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the D39 ECU connector.
    2. Measure the resistance of the wire harness side connector.

      Standard resistance

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      LIN (D39-10) - Body ground L - Body ground LIN line Always 10 kΩ or higher
      E (D39-17) - Body ground W - 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 D39 ECU connector.
    4. Measure the voltage of the connector.

      Standard voltage

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      +B1 (D39-1) - E (D39-17) R - W Battery Always 10 to 14 V
      IG (D39-18) - E (D39-17) Y - W Engine switch (IG) Engine switch OFF → ON (IG) Below 1 V → 10 to 14 V
      ACC (D39-19) - E (D39-17) SB - W Engine switch (ACC) Engine switch OFF → ON (ACC) Below 1 V → 10 to 14 V

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

  3. CHECK ECM 
    Fig 4: ECM Connector Terminal Identification
    GTY296104Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the A55 and B50 ECM connectors.
    2. Measure the resistance and voltage of the connectors.

      Standard

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      +B (A55-2) - E1 (B50-81) R - W-B Power source of ECM Engine switch ON (IG) 10 to 14 V
      +B2 (A55-1) - E1 (B50-81) W - W-B Power source of ECM Engine switch ON (IG) 10 to 14 V
      IGSW (A55-28) - E1 (B50-81) Y - W-B Ignition switch signal Engine switch ON (IG) 10 to 14 V
      E01 (B50-22) - Body ground W-B - Body ground Earth (ground) circuit of ECM Always Below 1 Ω
      E1 (B50-81) - Body ground W-B - Body ground Earth (ground) circuit of ECM Always Below 1 Ω

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

    3. Reconnect the A55 and B50 ECM connectors.
    4. Measure the voltage of the connectors.

      Standard voltage

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      STA (A55-48) - E1 (B50-81) V - W-B Starter relay operation signal Cranking 10 to 14 V
      ACCR (A55-13) - E1 (B50-81) B - W-B ACC relay cut signal output Engine switch ON (IG) 10 to 14 V
      TACH (A55-15) - E1 (B50-81) B - W-B Engine revolution start control signal output Idling Pulse generation
      STP (A55-36) - E1 (B50-81) W - W-B Stop light switch signal input Brake pedal depressed → Brake pedal released 7.5 to 14 V → Below 1.5V
      STAR (B50-63) - E1 (B50-81) R - W-B PNP switch signal input Engine switch ON 10 to 14 V

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

  4. CHECK STEERING LOCK ACTUATOR ASSEMBLY (STEERING LOCK ECU) 
    Fig 5: Steering Lock Actuator Assembly (Steering Lock ECU) Connector Terminal Identification
    GTY192342Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the D14 actuator connector.
    2. Measure the resistance and voltage of the wire harness side connector.

      Standard

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      B (D14-7) - Body ground B - Body ground +B power supply Always 10 to 14 V
      GND (D14-1) - Body ground W-B - Body ground Ground Always Below 1 Ω
      SGND (D14-2) - Body ground W - Body ground Ground Always Below 1 Ω
      LIN (D14-5) - Body ground R - Body ground LIN line Always 10 kΩ or higher

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

    3. Reconnect the D14 ECU connector.
    4. Measure the voltage of the connectors.

      Standard voltage

      Symbols (Terminal No.) Wiring Color Terminal Description Condition Specified Condition
      IG2 (D14-6) - Body ground V - Body ground Ignition power supply Engine switch ON (IG) 10 to 14 V
      SLP1 (D14-4) - GND (D14-1) BE - W-B Steering lock actuator UNLOCK position signal Steering is locked → released Below 1 V → 10 to 14 V
      IGE (D14-3) - GND (D14-1) P - W-B Power source for steering lock actuator Steering lock motor operate → not operate Below 1 V → 10 to 14 V
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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