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Home >> Lexus >> 2021 >> LC 500h >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Anti-Theft Systems >> Smart Access System (For Start) - Symptom Tests (2 Of 2) >> SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) >> Unable to Unlock Steering Wheel (Hybrid Control System cannot Start) [01/2017 - 05/2023] >> Procedure

Unable to Unlock Steering Wheel (Hybrid Control System cannot Start) [01/2017 - 05/2023]: Procedure

  1. CHECK POWER SOURCE MODE CHANGING FUNCTION (SWITCH CONDITION) 
    1. Check the power source mode change.

      Refer to OPERATION CHECK [01/2017 - 05/2023]

      OK

      The power source mode changes to on (IG).

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) (Power Source Mode does not Change to ON (IG and ACC)). Refer to  Power Source Mode does not Change to ON (IG and ACC) [01/2017 - 05/2023] 

    Result: 

    OK 

    See step  2

  2. CHECK INDICATOR 
    1. With the power switch on (IG), check that push power switch while turning steering wheel in either direction is displayed on the multi-information display in the combination meter assembly.

      Result

      Result Proceed to
      Push power switch while turning steering wheel in either direction is displayed. A
      Push power switch while turning steering wheel in either direction is not displayed. B

    Result: 

    B 

    See step  4

    Result: 

    A 

    See step  3

  3. CHECK STEERING UNLOCK 
    1. Turn the steering wheel left and right, and then press the power switch.
    2. Check that the steering is unlocked.

      Result

      Result Proceed to
      The steering is unlocked. A
      The steering is not unlocked. B

    Result: 

    A 

    END (STEERING LOCK IS NORMAL) 

    Result: 

    B 

    See step  4

  4. CHECK FOR DTC 
    1. Check for DTCs and note any DTCs that are output.

      Body Electrical > Smart Access > Trouble Codes 

      Body Electrical > Power Source Control > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output. A
      DTCs are output. B

    Result: 

    B 

    GO TO DIAGNOSTIC PROCEDURE INDICATED BY OUTPUT DTC. Refer to  DIAGNOSTIC TROUBLE CODE CHART [01/2017 - 06/2019]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [06/2019 - 04/2020]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [04/2020 - 05/2023] 

    Result: 

    A 

    See step  5

  5. READ VALUE USING TECHSTREAM (UNLOCK REQUEST RECEIVE) 
    1. Enter the following menus: Body Electrical / Smart Access / Data List.
    2. Read the Data List according to the display on the Techstream.

      Body Electrical > Smart Access > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Unlock Request Receive Status of steering unlock command from certification ECU (smart key ECU assembly) OK or NG OK: Unlock request signal received within 10 seconds of power switch being turned on (IG) or on (ACC) or of an hybrid control system start operation being performed
      NG: Power switch not turned on (IG) or on (ACC) and hybrid control system start operation not being performed
      • The hybrid control system cannot be started when an unlock request signal cannot be received.
      • If OK is not displayed even though the steering unlock conditions are met, the certification ECU (smart key ECU assembly) may be malfunctioning.

      Body Electrical > Smart Access > Data List 

      Tester Display
      Unlock Request Receive

      OK

      Within 10 seconds of turning the power switch on (ACC) or on (IG) or starting the hybrid control system, the Data List item changes to "OK".

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  14

    Result: 

    OK 

    See step  6

  6. READ VALUE USING TECHSTREAM (S CODE CHECK) 
    1. Read the Data List according to the display on the Techstream.

      Body Electrical > Smart Access > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      S Code Check S code verification result OK or NG OK: Verification result normal
      NG: Verification result abnormal      		 When NG is displayed:
      • The ID code for the certification ECU (smart key ECU assembly) or ID code box (immobilizer code ECU) is not registered, or the certification ECU (smart key ECU assembly) or ID code box (immobilizer code ECU) is malfunctioning.
      • The steering cannot be locked.
      • The steering cannot be unlocked (the hybrid control system cannot be started).

      Body Electrical > Smart Access > Data List 

      Tester Display
      S Code Check

      OK

      "OK" is displayed on the Techstream.

      HINT: 

      Reasons for verification failure:

      • The certification ECU (smart key ECU assembly) or ID code box (immobilizer code ECU) is malfunctioning.
      • There is a problem with the communication between ECUs.
      • An ECU is replaced, but is not registered.
      • An ECU is replaced with an ECU which has a code already stored in it.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  7

  7. READ VALUE USING TECHSTREAM (L CODE CHECK) 
    1. Read the Data List according to the display on the Techstream.

      Body Electrical > Smart Access > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      L Code Check L code verification result OK or NG OK: Verification result normal
      NG: Verification result abnormal      		 When NG is displayed:
      • The ID code for the ID code box (immobilizer code ECU) or steering lock ECU (steering lock actuator or upper bracket assembly) is not registered, or the ID code box (immobilizer code ECU) or steering lock ECU (steering lock actuator or upper bracket assembly) is malfunctioning.
      • The steering cannot be locked.
      • The steering cannot be unlocked (the hybrid control system cannot be started).

      Body Electrical > Smart Access > Data List 

      Tester Display
      L Code Check

      OK

      "OK" is displayed on the Techstream.

      HINT: 

      Reasons for verification failure:

      • The steering lock ECU (steering lock actuator or upper bracket assembly) or ID code box (immobilizer code ECU) is malfunctioning.
      • There is a problem with the communication between ECUs.
      • An ECU is replaced, but is not registered.
      • An ECU is replaced with an ECU which has a code already stored in it.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  12

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) - POWER SUPPLY AND BODY GROUND) 
    1. Disconnect the steering lock ECU (steering lock actuator or upper bracket assembly) connector.
      GTY819254Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Steering Lock ECU (Steering Lock Actuator or Upper Bracket Assembly))
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P14-1 (GND) - Body ground Always Below 1 Ω
      NOTE:

      If the result is not as specified, check for looseness in the ground cable connection.

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

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      P14-7 (B) - Body ground Power switch off 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. CHECK STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) (MOTOR ACTIVATION COMMAND SIGNAL) 
    1. Resconnect the steering lock ECU (steering lock actuator or upper bracket assembly) connector.
    2. Using an oscilloscope, check the waveform.

      OK

      Item Content
      Tester Connection P14-3 (IGE) - P14-1 (GND)
      Tool Setting 2 V/DIV., 200 ms./DIV.
      Condition Any door opened when conditions below met, and then steering lock motor activated:
      • Shift state park (P)
      • Steering lock unlocked in advance by carrying key and turning power switch on (IG)
      • After above conditions met, power switch turned off
      Specified Condition Pulse generation
      (See waveform)

      HINT: 

      • When taking measurements when the lock motor is stopped, it is not necessary to perform any operations.
      • In order to take measurements when the lock motor is operating, perform either of the following operations:
        • To unlock the steering, carry the key and turn the power switch on (ACC) or on (IG).
        • To lock the steering, turn the power switch off with the shift state park (P), and then open a door.
      GTY776316Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Steering Lock ECU (Steering Lock Actuator or Upper Bracket Assembly))
      *b Steering Lock Motor not Operating
      *c Steering Lock Motor Operating
      *d Waveform

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY). Refer to  DISASSEMBLY [01/2017 - 05/2023] 

    Result: 

    NG 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY)) 
    1. Disconnect the P14 steering lock ECU (steering lock actuator or upper bracket assembly) connector.
    2. Disconnect the P66 certification ECU (smart key ECU assembly) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P14-3 (IGE) - P66-25 (SLR+) Always Below 1 Ω
      P14-3 (IGE) or P66-25 (SLR+) - Other terminals and body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  11

  11. CHECK STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) 
    1. Reconnect the steering lock ECU (steering lock actuator or upper bracket assembly) connector.
    2. Reconnect the P66 certification ECU (smart key ECU assembly) connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      P14-3 (IGE) - Body ground Always 11 to 14 V
      GTY825405Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Steering Lock ECU (Steering Lock Actuator or Upper Bracket Assembly))

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [01/2017 - 05/2023] 

    Result: 

    NG 

    REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY). Refer to  DISASSEMBLY [01/2017 - 05/2023] 

  12. CHECK STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) 
    1. Replace the steering lock ECU (steering lock actuator or upper bracket assembly) with a new one.

      HINT: 

    2. Read the Data List according to the display on the Techstream.

      Body Electrical > Smart Access > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      L Code Check L code verification result OK or NG OK: Verification result normal
      NG: Verification result abnormal      		 When NG is displayed:
      • The ID code for the ID code box (immobilizer code ECU) or steering lock ECU (steering lock actuator or upper bracket assembly) is not registered, or the ID code box (immobilizer code ECU) or steering lock ECU (steering lock actuator or upper bracket assembly) is malfunctioning.
      • The steering cannot be locked.
      • The steering cannot be unlocked (the hybrid control system cannot be started).

      Body Electrical > Smart Access > Data List 

      Tester Display
      L Code Check

      OK

      "OK" is displayed on the Techstream.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END (STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) WAS DEFECTIVE) 

    Result: 

    NG 

    REPLACE ID CODE BOX (IMMOBILIZER CODE ECU). Refer to  REMOVAL [01/2017 - 05/2023] 

  13. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 
    1. Replace the certification ECU (smart key ECU assembly) with a new one and perform registration again.

      HINT: 

    2. Read the Data List according to the display on the Techstream.

      Body Electrical > Smart Access > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      S Code Check S code verification result OK or NG OK: Verification result normal
      NG: Verification result abnormal      		 When NG is displayed:
      • The ID code for the certification ECU (smart key ECU assembly) or ID code box (immobilizer code ECU) is not registered, or the certification ECU (smart key ECU assembly) or ID code box (immobilizer code ECU) is malfunctioning.
      • The steering cannot be locked.
      • The steering cannot be unlocked (the hybrid control system cannot be started).

      Body Electrical > Smart Access > Data List 

      Tester Display
      S Code Check

      OK

      "OK" is displayed on the Techstream.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) WAS DEFECTIVE) 

    Result: 

    NG 

    REPLACE ID CODE BOX (IMMOBILIZER CODE ECU). Refer to  REMOVAL [01/2017 - 05/2023] 

  14. CHECK STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) 
    1. Measure the voltage according to the value(s) in the table below.
      GTY825404Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Steering Lock ECU (Steering Lock Actuator or Upper Bracket Assembly))

      Standard Voltage

      Tester Connection Condition Specified Condition
      P14-4 (SLP1) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  17

    Result: 

    OK 

    See step  15

  15. READ VALUE USING TECHSTREAM (STEERING UNLOCK) 
    1. Check that the steering is locked.
    2. Read the Data List according to the display on the Techstream.

      Body Electrical > Smart Access > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Steering Unlock Steering lock ECU (steering lock actuator or upper bracket assembly) unlock confirmation status Unset or Set Unset: Unlock not confirmed
      Set: Unlock confirmed      		 When Unset is displayed, the steering is not unlocked (the hybrid control system cannot be started).

      Body Electrical > Smart Access > Data List 

      Tester Display
      Steering Unlock

      OK

      "Set" is displayed on the Techstream.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY). Refer to  DISASSEMBLY [01/2017 - 05/2023] 

    Result: 

    OK 

    See step  16

  16. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 
    1. Replace the certification ECU (smart key ECU assembly) with a new one.

      Refer to REMOVAL [01/2017 - 05/2023]

    2. Perform registration.

      Refer to REGISTRATION [01/2017 - 09/2018] , or refer to REGISTRATION [09/2018 - 04/2020] , or refer to REGISTRATION [04/2020 - 05/2023]

    3. Read the Data List according to the display on the Techstream.

      Body Electrical > Smart Access > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Unlock Request Receive Status of steering unlock command from certification ECU (smart key ECU assembly) OK or NG OK: Unlock request signal received within 10 seconds of power switch being turned on (IG) or on (ACC) or of an hybrid control system start operation being performed
      NG: Power switch not turned on (IG) or on (ACC) and hybrid control system start operation not being performed
      • The hybrid control system cannot be started when an unlock request signal cannot be received.
      • If OK is not displayed even though the steering unlock conditions are met, the certification ECU (smart key ECU assembly) may be malfunctioning.

      Body Electrical > Smart Access > Data List 

      Tester Display
      Unlock Request Receive

      OK

      Within 10 seconds of turning the power switch on (ACC) or on (IG) or starting the hybrid control system, the Data List item changes to "OK".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) WAS DEFECTIVE) 

    Result: 

    NG 

    REPLACE ID CODE BOX (IMMOBILIZER CODE ECU). Refer to  REMOVAL [01/2017 - 05/2023] 

  17. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY)) 
    1. Disconnect the P14 steering lock ECU (steering lock actuator or upper bracket assembly) connector.
    2. Disconnect the JP66 certification ECU (smart key ECU assembly) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P14-4 (SLP1) - JP66-14 (SLP) Always Below 1 Ω
      P14-4 (SLP1) or JP66-14 (SLP) - Other terminals and body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  18

  18. CHECK STEERING LOCK ECU (STEERING LOCK ACTUATOR ASSEMBLY) 
    1. Replace the steering lock ECU (steering lock actuator or upper bracket assembly) with a new one.

      Refer to DISASSEMBLY [01/2017 - 05/2023]

    2. Perform registration.

      Refer to REGISTRATION [01/2017 - 09/2018] , or refer to REGISTRATION [09/2018 - 04/2020] , or refer to REGISTRATION [04/2020 - 05/2023]

    3. Read the Data List according to the display on the Techstream.

      Body Electrical > Smart Access > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Unlock Request Receive Status of steering unlock command from certification ECU (smart key ECU assembly) OK or NG OK: Unlock request signal received within 10 seconds of power switch being turned on (IG) or on (ACC) or of an hybrid control system start operation being performed
      NG: Power switch not turned on (IG) or on (ACC) and hybrid control system start operation not being performed
      • The hybrid control system cannot be started when an unlock request signal cannot be received.
      • If OK is not displayed even though the steering unlock conditions are met, the certification ECU (smart key ECU assembly) may be malfunctioning.

      Body Electrical > Smart Access > Data List 

      Tester Display
      Unlock Request Receive

      OK

      Within 10 seconds of turning the power switch on (ACC) or on (IG) or starting the hybrid control system, the Data List item changes to "OK".

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END (STEERING LOCK ECU (STEERING LOCK ACTUATOR OR UPPER BRACKET ASSEMBLY) WAS DEFECTIVE) 

    Result: 

    NG 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [01/2017 - 05/2023] 

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