LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2009 >> LS 460 AWD >> Repair and Diagnosis >> Accessories & Equipment >> Cruise Control Systems >> Cruise Control >> Dynamic Radar Cruise Control System >> DTC C1A05 Stop Light Switch Circuit >> Inspection Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Inspection Procedure

  1. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH) 
    1. Check the Data List for proper functioning of the stop light switch.

      Radar Cruise 

      RADAR CRUISE REFERENCE CHART

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Light SW 1 M-CPU Stop light switch signal (Main CPU)/ON or OFF OK: Brake pedal is depressed
      OFF: Brake pedal is released      		 -
      Stop Light SW 2 M-CPU Stop light switch signal (Main CPU)/ON or OFF OK: Brake pedal is depressed
      OFF: Brake pedal is released      		 -
      Stop Light SW 1 S-CPU Stop light switch signal (Sub CPU)/ON or OFF OK: Brake pedal is depressed
      OFF: Brake pedal is released      		 -

      OK: 

      Display changes according to brake pedal operation described in above table. 

      NG: Go to step 2 

      OK: REPLACE DRIVING SUPPORT ECU  (See REMOVAL )

  2. INSPECT FUSE (STOP, ECU-IG) 
    1. Remove the STOP fuse from the main body ECU.
    2. Remove the ECU-IG fuse from the engine room No. 2 junction block.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      STANDARD RESISTANCE REFERENCE CHART

      Tester Connection Condition Specified Condition
      STOP fuse Always Below 1 Ω
      ECU-IG fuse Always Below 1 Ω

      NG: REPLACE FUSE 

      OK: Go to next step 

  3. INSPECT STOP LIGHT SWITCH ASSEMBLY 
    1. Remove the stop light switch (see STOP LIGHT SWITCH ).
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      STANDARD RESISTANCE REFERENCE CHART

      Tester Connection Switch Condition Specified Condition
      1 - 2 Pushed 10 kΩ or higher
      1 - 2 Not pushed Below 1 Ω
      3 - 4 Not pushed Below 1 Ω
      3 - 4 Pushed 10 kΩ or higher
      Fig 1: Inspecting Stop Light Switch Assembly
      G04951422Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      NG: REPLACE STOP LIGHT SWITCH ASSEMBLY  (See STOP LIGHT SWITCH )

      OK: Go to next step 

  4. CHECK HARNESS AND CONNECTOR (ECU - BATTERY) 
    1. Disconnect the A33 ECU connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      STANDARD VOLTAGE REFERENCE CHART

      Tester Connection Switch Condition Specified Condition
      A33-11 (STP-) - Body ground Brake pedal is depressed Below 1 V
      A33-11 (STP-) - Body ground Brake pedal is released 11 to 14 V
      A33-34 (ST1-) - Body ground Engine switch is on (IG), brake pedal is released 11 to 14 V
      A33-34 (ST1-) - Body ground Engine switch is on (IG), brake pedal is depressed Below 1 V
      Fig 2: Identifying A33 ECU Connector Terminals
      G05854402Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

      OK: REPLACE DRIVING SUPPORT ECU  (See REMOVAL )

scientia non olet · About LEMON Manuals