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Terminals Of Ecu

  1. SKID CONTROL ECU 
    Fig 1: Identifying Terminals Of ECU - A19
    G04949587Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    CONNECTOR TERMINAL SYMBOLS REFERENCE

    Terminal No. (Symbols) Terminal Description
    A19-1 (GND) Skid control ECU ground
    A19-2
    • (Not used)
    A19-3 (FRR-) Front pressure decrease linear solenoid RH (-) output
    A19-4 (FRR+) Front pressure decrease linear solenoid RH (+) output
    A19-5 (SMC1) Master cut solenoid 1 output
    A19-6 (CA2L) CAN communication line 2 (Braking and Driving bus)
    A19-7 (CA2H) CAN communication line 2 (Braking and Driving bus)
    A19-8 (ENA) Capacitor signal output
    A19-9 (PCK1) Pressure sensor 1 stuck check output
    A19-10 (RL-) Rear wheel speed sensor LH input
    A19-11 (RL+) Rear wheel speed sensor LH power supply output
    A19-12
    • (Not used)
    A19-13
    • (Not used)
    A19-14 (PMC1) Master cylinder pressure sensor 1 signal input
    A19-15 (FR-) Front wheel speed sensor RH input
    A19-16 (FR+) Front wheel speed sensor RH power supply output
    A19-17 (FRA+) Front pressure increase linear solenoid RH (+) output
    A19-18 (FRA-) Front pressure increase linear solenoid RH (-) output
    A19-19 (RLA+) Rear pressure increase linear solenoid LH (+) output
    A19-20 (RLA-) Rear pressure increase linear solenoid LH (-) output
    A19-21 (SS) Stroke simulator cut solenoid output
    A19-22 (BZ) Skid control buzzer output
    A19-23 (SP1) Speed signal output to combination meter
    A19-24
    • (Not used)
    A19-25 (CTY) Start power supply input (Door)
    A19-26 (PAC1) Accumulator pressure sensor 1 signal input
    A19-27 (VCM) Pressure sensor 1 power supply output
    A19-28 (E) Pressure sensor 1 ground
    A19-29 (+BI3) +B Battery 3
    A19-30
    • (Not used)
    A19-31 (BSO3) Stroke simulator cut solenoid power supply output
    A19-32 (BSO1) SMC1 power supply output
    A19-33 (RLR-) Rear pressure decrease linear solenoid LH (-) output
    A19-34 (RLR+) Rear pressure decrease linear solenoid LH (+) output
    A19-35 (MR1) Motor relay 1 power supply output
    A19-36 (R1-) Motor relay 1 output
    A19-37 (MTT) Motor relay test input
    A19-38 (CBI1) Capacitor power supply input 1
    A19-39
    • (Not used)
    A19-40
    • (Not used)
    A19-41 (VBZ) Skid control buzzer power supply output
    A19-42 (PRL) Rear wheel cylinder pressure sensor LH signal input
    A19-43 (+BI1) +B Battery 1
    A19-44 (PFR) Front wheel cylinder pressure sensor RH signal input
    A19-45 (LBL) Brake fluid level warning switch input
    A19-46 (IG1) IG1 power supply
    Fig 2: Identifying Terminals Of ECU - A20
    G04949588Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    CONNECTOR TERMINAL SYMBOLS REFERENCE

    Terminal No. (Symbols) Terminal Description
    A20-1 (SKS2) Brake pedal stroke sensor signal 2 input
    A20-2
    • (Not used)
    A20-3 (SKS) Brake pedal stroke sensor signal 1 input
    A20-4 (SKG) Brake pedal stroke sensor ground
    A20-5 (VCSK) Brake pedal stroke sensor power supply output
    Fig 3: Identifying Terminals Of ECU - A21
    G04949589Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    CONNECTOR TERMINAL SYMBOLS REFERENCE

    Terminal No. (Symbols) Terminal Description
    A21-1 (GND4) Skid control ECU ground
    A21-2
    • (Not used)
    A21-3 (FLR-) Front pressure decrease linear solenoid LH (-) output
    A21-4 (FLR+) Front pressure decrease linear solenoid LH (+) output
    A21-5 No pin
    A21-6 (SMC2) Master cut solenoid 2 output
    A21-7 (PCK2) Pressure sensor 2 stuck check output
    A21-8 (CANL) CAN communication line 3 (V Bus)
    A21-9 (CANH) CAN communication line 3 (V Bus)
    A21-10 (RR-) Rear wheel speed sensor RH input
    A21-11 (RR+) Rear wheel speed sensor RH power supply output
    A21-13
    • (Not used)
    A21-14 (PMC2) Master cylinder pressure sensor 2 signal input
    A21-15 (FL-) Front wheel speed sensor LH input
    A21-16 (FL+) Front wheel speed sensor LH power supply output
    A21-17 (FLA+) Front pressure increase linear solenoid LH (+) output
    A21-18 (FLA-) Front pressure increase linear solenoid LH (-) output
    A21-19 No pin
    A21-20 (RRA+) Rear pressure increase linear solenoid RH (+) output
    A21-21 (RRA-) Rear pressure increase linear solenoid RH (-) output
    A21-22 (+BI4) +B Battery 4
    A21-23
    • (Not used)
    A21-24 (TS) Signal check (Test mode) input
    A21-25 (STP) Stop light switch input
    A21-26 No pin
    A21-27
    • (Not used)
    A21-28 (VCM2) Pressure sensor 2 power supply output
    A21-29 (CA1L) CAN communication line 1 (Steering Bus)
    A21-30 (CA1H) CAN communication line 1 (Steering Bus)
    A21-31
    • (Not used)
    A21-32 (BSO2) SMC2 power supply output
    A21-33 (RRR-) Rear pressure decrease linear solenoid RH (-) output
    A21-34 (RRR+) Rear pressure decrease linear solenoid RH (+) output
    A21-35 No pin
    A21-36 (MR2) Motor relay 2 power supply output
    A21-37 (R2-) Motor relay 2 output
    A21-38 (+BI2) +B Battery 2
    A21-39
    • (Not used)
    A21-40 (CBI2) Capacitor power supply input 2
    A21-41 (FAIL) Capacitor signal input
    A21-42 No pin
    A21-43 (PRR) Rear wheel cylinder pressure sensor RH signal input
    A21-44 (E2) Pressure sensor 2 ground
    A21-45 (PFL) Front wheel cylinder pressure sensor LH signal input
    A21-46 (IG2) IG2 power supply
  2. CHECK SKID CONTROL ECU 
    1. Disconnect the A19 and A21 ECU connectors and measure the voltage or resistance on the wire harness side.
      Fig 4: Identifying Skid Control ECU Connector (A19 And A21)
      G04949590Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      Voltage cannot be measured with the connector connected to the skid control ECU as the connector is watertight.

      CONNECTOR TERMINAL SYMBOLS REFERENCE

      Terminal No. (Symbols) Wiring Color Terminal Description Condition Specified Condition
      A19-1 (GND) - Body ground W-B - Body ground Skid control ECU ground Always Below 1 Ω
      A19-29 (+BI3) - Body ground O - Body ground +B input 3 Always 11 to 14 V
      A19-43 (+BI1) - Body ground B - Body ground +B input 1 Always 11 to 14 V
      A19-45 (LBL) - Body ground W - Body ground Brake fluid level warning switch input Brake fluid level is minimum level --> maximum level 1.9 to 2.1 kΩ --> Below 1 Ω
      A19-46 (IG1) - Body ground L - Body ground IG1 power supply Engine switch on (IG) 11 to 14 V
      A21-1 (GND4) - Body ground W-B - Body ground Skid control ECU ground Always Below 1 Ω
      A21-22 (+BI4) - Body ground 0 - Body ground +B input 4 Always 11 to 14 V
      A21-24 (TS)-DLC Terminal - Signal check (test mode) input Always Below 1 Ω
      A21-25 (STP) - Body ground B - Body ground Stop light switch input Stop light switch ON --> OFF (Brake pedal depressed --> released) 8 to 14 V --> Below 1.5 V
      A21-38 (+BI2) - Body ground GR - Body ground +B input 2 Always 11 to 14 V
      A21-46 (IG2) - Body ground R - Body ground IG2 power supply Engine switch on (IG) 11 to 14 V
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