2012 Lexus IS FFACTORY OEM SERVICE PROCEDURE

Terminals Of Ecu

  1. TERMINALS OF ECU 
    Fig 1: Identifying Terminals of ECU
    GTY258227Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    TEXT IN ILLUSTRATION

    *1 Component without harness connected
    (Skid Control ECU)
    Terminal No. (Symbol) Terminal Description
    1 (GND1) Skid control ECU ground
    2 (STP1) Stop light switch input
    4 (RL-) Rear wheel speed LH (-) signal input
    5 (RL+) Rear wheel speed LH (+) power supply output
    6 (FR-) Front wheel speed RH (-) signal input
    7 (FR+) Front wheel speed RH (+) power supply output
    9 (FLO)*1 Front wheel speed LH signal output
    10 (FRO)*1 Front wheel speed RH signal output
    11 (SP1) Speed signal output for speedometer
    12 (+BS) Solenoid relay power supply
    13 (GND2) Pump motor ground
    14 (CANL) CAN communication line L
    16 (RR-) Rear wheel speed RH (-) signal input
    17 (RR+) Rear wheel speed RH (+) power supply output
    18 (FL-) Front wheel speed LH (-) signal input
    19 (FL+) Front wheel speed LH (+) power supply output
    21 (BZ)*2 Skid control buzzer output
    22 (STP2) Stop light control relay input
    24 (BM) Motor relay power supply
    25 (CANH) CAN communication line H
    27 (FSW+) Brake pedal load sensing switch input
    29 (PKB) Parking brake switch input
    30 (CSW) VSC OFF switch input
    31 (STPO) Stop light control relay output
    33 (TS) Sensor check input
    34 (IG1) ECU power supply

    *1: w/ AFS

    *2: w/ Dynamic radar cruise control system

  2. TERMINAL INSPECTION 
    1. Disconnect the connectors and measure the voltage or resistance on the wire harness side.
      Fig 2: Identifying Terminals of ECU
      GTY280655Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Skid Control ECU)

      HINT: 

      Voltage cannot be measured with the connectors connected to the skid control ECU as the connectors are watertight.

      STANDARD

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      A62-1 (GND1) - Body ground W-B - Body ground Skid control ECU ground Always Below 1 Ω
      A62-2 (STP1) - Body ground R-B - Body ground Stop light switch input Stop light switch ON → OFF
      (Brake pedal depressed → released)      		 8 to 14 V
      → Below 1.5 V
      A62-12 (+BS) - Body ground BR - Body ground Solenoid relay power supply Always 11 to 14 V
      A62-13 (GND2) - Body ground W-B - Body ground Pump motor ground Always Below 1 Ω
      A62-21 (BZ) - Body ground*1 Y-B - Body ground Skid control buzzer output Engine switch on (IG), buzzer not sounding 6 to 10 V
      A62-22 (STP2) - Body ground R-W - Body ground Stop light control relay input Stop light switch ON → OFF
      (Brake pedal depressed → released)      		 8 to 14 V
      → Below 1.5 V
      A62-24 (BM) - Body ground W - Body ground Motor relay power supply Always 11 to 14 V
      A62-27 (FSW+) - Body ground G-O - Body ground Brake pedal load sensing switch input Brake pedal load sensing switch OFF → ON
      (Brake pedal depressed → released)      		 950 to 1050 Ω → 203 to 223 Ω
      A62-29 (PKB) - Body ground Y - Body ground Parking brake switch input Engine switch on (IG), parking brake switch OFF → ON Below 1 Ω → 10 kΩ or higher
      A62-30 (CSW) - Body ground L-Y - Body ground VSC OFF switch input VSC OFF switch held ON → OFF (Released) Below 25 Ω → 10 kΩ or higher
      A62-31 (STPO) - Body ground L - Body ground Stop light control relay output Engine switch on (IG) 11 to 14 V
      A62-34 (IG1) - Body ground B-W - Body ground ECU power supply Engine switch on (IG) 11 to 14 V

      *1: w/ Dynamic radar cruise control system

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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.