Lexus IS250 · Service Manual ENGINE

TERMINALS OF ECU

System information


CHECK POWER SOURCE CONTROL ECU
B075721E20

  1. Disconnect the J55 ECU connector.

  2. Measure the voltage and resistance of the wire harness side connector.

    Symbols (Terminal No.)
    		 Wiring Color
    		 Terminal Description
    		 Condition
    		 Specified Condition
    AM1 (J55-33) - Body ground
    		 O - Body ground
    		 +B power supply
    		 Always
    		 10 to 14 V
    AM2 (J55-12) - Body ground
    		 O - Body ground
    		 +B power supply
    		 Always
    		 10 to 14 V
    SSW1 (J55-14) - Body ground
    		 B - Body ground
    		 Engine switch signal
    		 Engine switch pushed
    		 Below 1 Ω
    SSW1 (J55-14) - Body ground
    		 B - Body ground
    		 Engine switch signal
    		 Engine switch not pushed
    		 10 kΩ or higher
    SSW2 (J55-37) - Body ground
    		 SB - Body ground
    		 Engine switch signal
    		 Engine switch pushed
    		 Below 1 Ω
    SSW2 (J55-37) - Body ground
    		 SB - Body ground
    		 Engine switch signal
    		 Engine switch not pushed
    		 10 kΩ or higher
    GND2 (J55-6) - Body ground
    		 W-B - Body ground
    		 Ground
    		 Always
    		 Below 1 Ω
    LIN1 (J55-30) - Body ground
    		 V - Body ground
    		 LIN line
    		 Always
    		 10 kΩ or higher
    MPX1 (J55-7) - Body ground
    		 GR - Body ground
    		 MPX line
    		 Always
    		 10 kΩ or higher
    MPX2 (J55-24) - Body ground
    		 GR - Body ground
    		 MPX 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 J55 ECU connector.

  4. Measure the voltage of the connector.

    Symbols (Terminal No.)
    		 Wiring Color
    		 Terminal Description
    		 Condition
    		 Specified Condition
    ACCD (J55-11) - GND2 (J55-6)
    		 LG - W-B
    		 ACC signal
    		 Engine switch on (ACC)
    		 8 to 14 V
    ACCD (J55-11) - GND2 (J55-6)
    		 LG - W-B
    		 ACC signal
    		 Engine switch off
    		 Below 1 V
    IG1D (J55-34) - GND2 (J55-6)
    		 P - W-B
    		 IG1 signal
    		 Engine switch on (IG)
    		 8 to 14 V
    IG1D (J55-34) - GND2 (J55-6)
    		 P - W-B
    		 IG1 signal
    		 Engine switch on (ACC)
    		 Below 1 V
    IG2D (J55-35) - GND2 (J55-6)
    		 LG - W-B
    		 IG2 signal
    		 Engine switch on (IG)
    		 8 to 14 V
    IG2D (J55-35) - GND2 (J55-6)
    		 LG - W-B
    		 IG2 signal
    		 Engine switch on (ACC)
    		 Below 1 V
    STP (J55-1) - GND2 (J55-6)
    		 R - W-B
    		 Stop light signal
    		 Brake pedal depressed
    		 8 to 14 V
    STP (J55-1) - GND2 (J55-6)
    		 R - W-B
    		 Stop light signal
    		 Brake pedal released
    		 Below 1 V
    SLR+ (J55-32) - GND2 (J55-6)
    		 W - W-B
    		 Steering lock motor signal
    		 Steering lock motor operating
    		 Below 1 V
    SLR+ (J55-32) - GND2 (J55-6)
    		 W - W-B
    		 Steering lock motor signal
    		 Steering lock motor does not operate
    		 10 to 14 V
    SLP (J55-26) - GND2 (J55-6)
    		 R - W-B
    		 Steering lock actuator position signal
    		 Steering lock is locked
    		 Pulse generation
    (See waveform 3)
    SLP (J55-26) - GND2 (J55-6)
    		 R - W-B
    		 Steering lock actuator position signal
    		 Steering lock is released
    		 Pulse generation
    (See waveform 3)
    SPD (J55-19) - GND2 (J55-6)
    		 P - W-B
    		 Vehicle speed signal
    		 Engine switch on (IG), rotate rear wheel slowly
    		 Pulse generation
    (See waveform 1)
    TACH (J55-2) - GND2 (J55-6)
    		 W - W-B
    		 Tachometer signal
    		 Engine running
    		 Pulse generation
    (See waveform 2)
    P (J55-5) - GND2 (J55-6) *3
    		BR - W-B
    		 Shift lock signal
    		 Shift lever P position
    		 8 to 14 V
    P (J55-5) - GND2 (J55-6) *3
    		BR - W-B
    		 Shift lock signal
    		 Shift lever not P position
    		 Below 1 V
    CTSW (J55-31) - GND2 (J55-6)
    		 LG - W-B
    		 Starter assist signal
    		 Brake pedal depressed, shift lever P position, engine switch is pushed once → on (IG)
    		 0.1 to 0.8 V *1
    → 8 to 14 V
    STSW (J55-39) - GND2 (J55-6)
    		 L - W-B
    		 Starter activation request signal
    		 Brake pedal (A/T) or clutch pedal (M/T) depressed, engine switch hold on (ST)
    		 8 to 14 V *2
    STR1 (J55-17) - GND2 (J55-6)
    		 SB - W-B
    		 Park/neutral position switch
    		 Shift lever P or N (A/T) position
    Clutch pedal depressed (M/T)
    		 Below 1 V
    STR2 (J55-15) - GND2 (J55-6)
    		 V - W-B
    		 Starter signal
    		 Brake pedal (A/T) or clutch pedal (M/T) depressed, shift lever P or N position (A/T), engine switch on (ST)
    		 8 to 14 V *2
    INDS (J55-4) - GND2 (J55-6)
    		 L - W-B
    		 Vehicle condition signal
    		 Brake pedal (A/T) or clutch pedal (M/T) depressed, shift lever P position (A/T).
    		 8 to 14 V
    INDW (J55-13) - GND2 (J55-6)
    		 BR - W-B
    		 Warning signal
    		 Brake pedal (A/T) or clutch pedal (M/T) depressed, shift lever P position (A/T), engine switch on (ACC, IG)
    		 8 to 14 V
    SWIL (J55-36) - GND2 (J55-6)
    		 Y - W-B
    		 Illumination signal
    		 Light control switch TAIL or HEAD
    		 8 to 14 V
    SKSW (J55-28) - GND2 (J55-6)
    		 B - W-B
    		 Key in vehicle signal
    		 Engine switch on (ACC, IG)
    		 Below 1 V

    HINT:
    *1: Voltage is output only when the engine is cranking.
    *2: Voltage is output for 0.3 seconds when engine is cranking start. Disconnect the E4 connector from the ECM before measuring the voltage.
    *3: A/T

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

  5. Using an oscilloscope, check the signal waveform of the ECU.

    1. I042329E01
      Waveform 1
      Waveform 1 (Reference): 
      Terminal No.
      		 J55-19 - Body ground
      Tool Setting
      		 5 V/DIV., 10 ms./DIV.
      Vehicle Condition
      		 Driving at approx. 20 km/h (12 mph)

      HINT:
      As the engine revolution speed increases, the wavelength shortens.

    2. I042330E01
      Waveform 2
      Waveform 2 (Reference): 
      Terminal No.
      		 J55-2 - Body ground
      Tool Setting
      		 5 V/DIV., 10 ms./DIV.
      Vehicle Condition
      		 Engine idling

      HINT:
      As the vehicle speed increases, the wavelength shortens.

    3. A130277E01
      Waveform 3
      Waveform 3 (Reference): 
      Terminal No.
      		 J55-26 - Body ground
      Tool Setting
      		 2 V/DIV., 100 ms./DIV.
      Vehicle Condition
      		 Steering lock / unlock

      HINT:
      As the steering lock increases, the wavelength shortens.


CHECK CERTIFICATION ECU
B108931E03

  1. Disconnect the P33 ECU connector.

  2. Measure the voltage and resistance of the wire harness side connector.

    Symbols (Terminal No.)
    		 Wiring Color
    		 Terminal Description
    		 Condition
    		 Specified Condition
    +B1 (P33-1) - Body ground
    		 L - Body ground
    		 +B power supply
    		 Always
    		 10 to 14 V
    IG (P33-18) - Body ground
    		 B - Body ground
    		 Ignition power supply
    		 Engine switch on (IG)
    		 10 to 14 V
    IG (P33-18) - Body ground
    		 B - Body ground
    		 Ignition power supply
    		 Engine switch off
    		 Below 1 V
    LIN (P33-10) - Body ground
    		 V - Body ground
    		 LIN line
    		 Always
    		 10 kΩ or higher
    E (P33-17) - 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.


CHECK ECM
A103802E13

  1. Disconnect the A5, E5, E4, E3 and E6 ECM connectors.

  2. Measure the voltage and resistance of the wire harness side connectors.

    Symbols (Terminal No.)
    		 Wiring Color
    		 Terminal Description
    		 Condition
    		 Specified Condition
    +B (A5-6) - Body ground
    		 B-R - Body ground
    		 Power source of ECM
    		 Engine switch on (IG)
    		 10 to 14 V
    +B1 (A5-5) - Body ground
    		 B-R - Body ground
    		 Power source of ECM
    		 Engine switch on (IG)
    		 10 to 14 V
    IGSW (A5-17) - Body ground
    		 B-W - Body ground
    		 Ignition switch signal
    		 Engine switch on (IG)
    		 10 to 14 V
    E01 (E5-2) - Body ground
    		 W-B - Body ground
    		 Ground
    		 Always
    		 Below 1 Ω
    E02 (E5-1) - Body ground
    		 W-B - Body ground
    		 Ground
    		 Always
    		 Below 1 Ω
    E03 (E3-6) - Body ground
    		 W-B - Body ground
    		 Ground
    		 Always
    		 Below 1 Ω
    E04 (E6-5) - Body ground
    		 W-B - Body ground
    		 Ground
    		 Always
    		 Below 1 Ω
    E05 (E6-3) - Body ground
    		 W-B - Body ground
    		 Ground
    		 Always
    		 Below 1 Ω
    E1 (E4-7) - Body ground
    		 BR - Body ground
    		 Ground
    		 Always
    		 Below 1 Ω
    EC (A5-2) - Body ground
    		 W-B - Body ground
    		 Ground
    		 Always
    		 Below 1 Ω
    ME01 (E3-4) - 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 A5, E5, E4, E3 and E6 ECM connectors.

  4. Measure the voltage of the connectors.

    Symbols (Terminal No.)
    		 Wiring Color
    		 Terminal Description
    		 Condition
    		 Specified Condition
    STA (A5-12) - E1 (E4-7)
    		 R - BR
    		 Starter relay operation signal
    		 Cranking
    		 10 to 14 V
    ACCR (A5-11) - E1 (E4-7)
    		 W-L - BR
    		 ACC relay cut signal (output)
    		 Engine switch on (IG)
    		 10 to 14 V
    TACH (A6-16) - E1 (E4-7)
    		 R-W - BR
    		 Engine revolution signal (output)
    		 Idling
    		 Pulse generation (see waveform 1)
    STP (A6-4) - E1 (E4-7)
    		 R-B - BR
    		 Stop light switch signal (input)
    		 Brake pedal depressed
    		 7.5 to 14 V
    STP (A6-4) - E1 (E4-7)
    		 R-B - BR
    		 Stop light switch signal (input)
    		 Brake pedal released
    		 Below 1.5 V
    STAR (E4-4) - E1 (E4-7)
    		 L-Y - BR
    		 PNP switch signal (input)
    		 Engine switch on (IG), shift position P or N
    		 10 to 14 V
    KSW (A5-23) - E1 (E4-7)
    		 L-R - BR
    		 Engine switch signal (input)
    		 Engine switch off
    		 4 to 6 V
    KSW (A5-23) - E1 (E4-7)
    		 L-R - BR
    		 Engine switch signal (input)
    		 When engine switch is pushed once
    		 10 to 14 V
    KSW (A5-23) - E1 (E4-7)
    		 L-R - BR
    		 Engine switch signal (input)
    		 Engine switch on (ACC)
    		 Below 1.5 V
    If the result is not as specified, the ECM may have a malfunction.

  5. I042330E01
    Using an oscilloscope, check the signal waveform of the ECM.
    Waveform 1 (Reference): 
    Terminal No.
    		 A6-16 - E7-4
    Tool Setting
    		 5 V/DIV., 10 ms./DIV.
    Vehicle Condition
    		 Engine idling

    HINT:
    As the vehicle speed increases, the wavelength shortens.


CHECK STEERING LOCK ECU
B106649E09

  1. Disconnect the J29 ECU connector.

  2. Measure the voltage and resistance of the wire harness side connector.

    Symbols (Terminal No.)
    		 Wiring Color
    		 Terminal Description
    		 Condition
    		 Specified Condition
    B (J29-7) - Body ground
    		 O - Body ground
    		 +B power supply
    		 Always
    		 10 to 14 V
    IG2 (J29-6) - Body ground
    		 LG - Body ground
    		 Ignition power supply
    		 Engine switch on (IG)
    		 10 to 14 V
    IG2 (J29-6) - Body ground
    		 LG - Body ground
    		 Ignition power supply
    		 Engine switch off
    		 Below 1 V
    GND (J29-1) - Body ground
    		 W-B - Body ground
    		 Ground
    		 Always
    		 Below 1 Ω
    SGND (J29-2) - Body ground
    		 W-B - Body ground
    		 Ground
    		 Always
    		 Below 1 Ω
    1. If the result is not as specified, there may be a malfunction on the wire harness side.

  3. Reconnect the J29 ECU connector.

  4. Measure the voltage of the connector.

    Symbols (Terminal No.)
    		 Wiring Color
    		 Terminal Description
    		 Condition
    		 Specified Condition
    SLP1 (J29-4) - GND (J29-1)
    		 R - W-B
    		 Steering lock actuator position signal
    		 Steering is locked
    		 10 to 14 V
    SLP1 (J29-4) - GND (J29-1)
    		 R - W-B
    		 Steering lock actuator position signal
    		 Steering is released
    		 Below 1 V
    1. If the result is not as specified, the ECU may have a malfunction.

← PROBLEM SYMPTOMS TABLEDIAGNOSIS SYSTEM →