LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2021 >> RC F Base >> Repair and Diagnosis >> Accessories & Equipment >> Cruise Control Systems >> Dynamic Radar Cruise Control System - Diagnostic Codes & Circuit Tests >> Dynamic Radar Cruise Control System >> Cruise Control Switch Circuit [01/2023 - ] >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Cruise Control Switch Circuit [01/2023 - ]: Procedure

  1. READ VALUE USING TECHSTREAM (Radar Cruise1) 
    1. Read the Data List according to the display on the Techstream.

      Powertrain > Radar Cruise1 > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Cancel Switch CANCEL switch status ON or OFF ON: CANCEL switch on
      OFF: CANCEL switch off
      -
      -SET Switch -SET switch status ON or OFF ON: -SET switch on
      OFF: -SET switch off
      -
      +RES Switch +RES switch status ON or OFF ON: +RES switch on
      OFF: +RES switch off
      -
      Cruise Main Switch Operation Condition Cruise control main switch status ON or OFF ON: Cruise control main switch pushed
      OFF: Cruise control main switch not pushed
      -

      Powertrain > Radar Cruise1 > Data List 

      Tester Display
      Cancel Switch
      -SET Switch
      +RES Switch
      Cruise Main Switch Operation Condition

      OK

      The value of each Data List item changes according to the operation of the cruise control main switch.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [01/2023 - ] 

    Result: 

    NG 

    See step  2

  2. INSPECT CRUISE CONTROL MAIN SWITCH 

    Refer to INSPECTION [11/2017 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE CRUISE CONTROL MAIN SWITCH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    OK 

    See step  3

  3. INSPECT STEERING PAD SWITCH ASSEMBLY 

    Refer to INSPECTION [11/2017 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE STEERING PAD SWITCH ASSEMBLY. Refer to  REMOVAL [11/2017 - ] 

    Result: 

    OK 

    See step  4

  4. INSPECT SPIRAL CABLE SUB-ASSEMBLY 

    Refer to INSPECTION [11/2017 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  REMOVAL [01/2023 - ] 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - ECM AND BODY GROUND) 
    1. Disconnect the A78 ECM connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      C25-7 (CCS) - A78-16 (CCS) Always Below 1 Ω
      C25-2 (ECC) - Body ground Always Below 1 Ω
      C25-7 (CCS) or A78-16 (CCS) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR