ENTRY AND START SYSTEM (for Start Function) Power Source Mode does not Change

DESCRIPTION

When the certification ECU (smart key ECU assembly) has detected the key inside the cabin before the brake pedal is depressed, the power source mode can be changed in the following order sequentially by pressing the engine switch: off → on (ACC) → on (IG) → off.

When one of the DTCs shown in the illustration below is detected, troubleshoot the DTC(s) by following the troubleshooting procedure relevant to the DTC(s). If the power source mode still cannot be changed normally, despite troubleshooting, one of the following may have occurred:


A01ENKYE07

WIRING DIAGRAM

A01EPT6E01

INSPECTION PROCEDURE

Tech Tips

If the vehicle is in key cancel mode, change to normal mode Click here.

PROCEDURE


  1. CHECK DTC OUTPUT


    1. Check whether DTC is output Click here.

      Result
      Display (DTC output) Proceed to
      No DTC output A
      DTC output B

    B

    GO TO ENTRY AND START SYSTEM (FOR START FUNCTION) (DIAGNOSTIC TROUBLE CODE CHART) Click here

    A

  2. CHECK ENTRY AND START SYSTEM

    A01EO1CE01

    1. Remove the battery of the electrical key transmitter Click here.

    2. With the brake pedal depressed, touch the LEXUS mark of the key to the engine switch.

    3. When operating the engine switch, check whether the engine switch changes to on (ACC) or on (IG).

      Tech Tips


      • When the electrical key transmitter cannot be verified even when it is in the operational area, the engine start check can be performed by removing the transmitter battery from the electrical key transmitter and holding the transmitter against the engine switch.

      • When performing the check, if the engine switch turns on (ACC) or on (IG), there is a problem with key certification inside the cabin.

      Result
      Result Proceed to
      Does not change to on (ACC) A
      Does not change to on (IG) B
      Does not change to on (ACC) and on (IG) C
      Changes to on (ACC) and on (IG) D

    B

    INSPECT FUSE (AM2) Click here

    C

    INSPECT FUSE (AM2) Click here

    D

    GO TO ENTRY AND START SYSTEM (FOR ENTRY FUNCTION) (ROOM OSCILLATOR DOES NOT RECOGNIZE KEY) Click here

    A

  3. INSPECT FUSE (AM2)


    1. Remove the AM2 fuse from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      AM2 fuse Always Below 1 Ω

    NG

    REPLACE FUSE

    OK

  4. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BATTERY AND BODY GROUND)

    A01EPHGE06

    1. Disconnect the E1, E2, 2A and 2D main body ECU connectors.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      E1-6 (AM1) - Body ground Always 11 to 14 V
      E2-1 (AM2) - Body ground Always 11 to 14 V
      2A-1 - Body ground Always 11 to 14 V
      Standard Resistance
      Tester Connection Condition Specified Condition
      E1-22 (ACCD) - 2D-45 Always Below 1 Ω
      2D-62 (GND2) - Body ground Always Below 1 Ω
      E1-22 (ACCD) or 2D-45 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE MAIN BODY ECU (COWL SIDE JUNCTION BLOCK LH)

  5. INSPECT FUSE (AM2)


    1. Remove the AM2 fuse from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      AM2 fuse Always Below 1 Ω

    NG

    REPLACE FUSE

    OK

  6. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BATTERY AND BODY GROUND)

    A01EPHGE05

    1. Disconnect the E1, E2, 2A and 2D main body ECU connectors.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      E1-6 (AM1) - Body ground Always 11 to 14 V
      E2-1 (AM2) - Body ground Always 11 to 14 V
      2A-1 - Body ground Always 11 to 14 V
      Standard Resistance
      Tester Connection Condition Specified Condition
      E1-3 (IG1D) - 2D-43 Always Below 1 Ω
      2D-62 (GND2) - Body ground Always Below 1 Ω
      E1-3 (IG1D) or 2D-43 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. INSPECT INTEGRATION NO.1 RELAY (IG2 RELAY)

    A01ESHKE02

    1. Remove the integration relay from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1B-8 - 1C-1 Battery voltage applied to terminals 1B-6 and 1B-7 Below 1 Ω
      1B-8 - 1C-1 Battery voltage not applied to terminals 1B-6 and 1B-7 10 kΩ or higher

    NG

    REPLACE INTEGRATION NO.1 RELAY

    OK

  8. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY [IG2 RELAY] - MAIN BODY ECU AND BODY GROUND)

    A01EOQCE03

    1. Disconnect the E2 main body ECU connector.

    2. Disconnect the 1B integration relay connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      E2-11 (IG2D) - 1B-6 Always Below 1 Ω
      1B-7 - Body ground Always Below 1 Ω
      E2-11 (IG2D) or 1B-6 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. INSPECT FUSE (IGN, IG2 MAIN)


    1. Remove the IGN and IG2 MAIN fuses from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      IGN fuse Always Below 1 Ω
      IG2 MAIN fuse Always Below 1 Ω

    NG

    REPLACE FUSE

    OK

  10. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY [IG2 RELAY] - STEERING LOCK ECU AND BATTERY)

    A01EOBKE02

    1. Disconnect the E26 steering lock ECU connector.

    2. Disconnect the 1B and 1C integration relay connectors.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      1C-1 - Body ground Always 11 to 14 V
      Standard Resistance
      Tester Connection Condition Specified Condition
      E26-6 (IG2) - 1B-8 Always Below 1 Ω
      E26-6 (IG2) or 1B-8 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE MAIN BODY ECU (COWL SIDE JUNCTION BLOCK LH)

  11. INSPECT FUSE (AM2)


    1. Remove the AM2 fuse from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      AM2 fuse Always Below 1 Ω

    NG

    REPLACE FUSE

    OK

  12. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BATTERY AND BODY GROUND)

    A01EQNYE03

    1. Disconnect the E1, E2 and 2D main body ECU connectors.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      E1-6 (AM1) - Body ground Always 11 to 14 V
      E2-1 (AM2) - Body ground Always 11 to 14 V
      Standard Resistance
      Tester Connection Condition Specified Condition
      2D-62 (GND2) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  13. INSPECT ENGINE SWITCH

    A01ERZSE06

    1. Disconnect the E18 engine switch connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      7 (SS1) - 5 (GND) Pushed Below 1 Ω
      2 (SS2) - 5 (GND) Pushed Below 1 Ω
      7 (SS1) - 5 (GND) Not pushed 10 kΩ or higher
      2 (SS2) - 5 (GND) Not pushed 10 kΩ or higher
      Result
      Result Proceed to
      OK A
      NG (for 3UR-FE) B
      NG (for 1UR-FE) C

    B

    REPLACE ENGINE SWITCH Click here

    C

    REPLACE ENGINE SWITCH Click here

    A

  14. CHECK HARNESS AND CONNECTOR (ENGINE SWITCH - MAIN BODY ECU AND BODY GROUND)

    A01EPINE06

    1. Disconnect the E1 main body ECU connector.

    2. Disconnect the E18 engine switch connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      E1-17 (SSW1) - E18-7 (SS1) Always Below 1 Ω
      E1-16 (SSW2) - E18-2 (SS2) Always Below 1 Ω
      E18-5 (GND) - Body ground Always Below 1 Ω
      E1-17 (SSW1) or E18-7 (SS1) - Body ground Always 10 kΩ or higher
      E1-16 (SSW2) or E18-2 (SS2) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE MAIN BODY ECU (COWL SIDE JUNCTION BLOCK LH)