Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Lexus >> 2007 >> ES 350 >> Repair and Diagnosis >> Accessories & Equipment >> Cruise Control Systems >> Cruise Control >> Dynamic Radar Cruise Control System >> DTC P0571 Brake Switch "A" Circuit >> Inspection Procedure

Inspection Procedure

NOTE: When the distance control ECU and/or ECM are replaced with a new one, initialization must be performed (See INSTALLATION  ).
  1. CHECK DTC 
    1. Check for a DTC (See DTC CHECK / CLEAR  ).

      Result 

      RESULT

      Condition Proceed to
      DTC C1249 and/or C1380 are not output A
      DTC C1249 and/or C1380 are output B

    B: GO TO ANTI-LOCK BRAKE SYSTEM  (See SYSTEM DESCRIPTION )

    A: Go to Next Step 

  2. READ VALUE ON INTELLIGENT TESTER 
    1. Connect the intelligent tester to the DLC3.
    2. Turn the engine switch on (IG), and turn the intelligent tester main switch on.
    3. Check the DATA LIST for proper functioning of the stop light switch.

      ECM (Cruise control): 

      DATA LIST

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      STP LIGHT SW M Stop light switch signal (Main CPU) / ON or OFF ON: Brake pedal depressed
      OFF: Brake pedal released
      -

      OK: When the brake pedal is operated, the display changes as shown above. 

    OK REPLACE ECM  (See REMOVAL )

    NG: Go to Next Step 

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

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connection Switch Condition Specified Condition
      1-2 Switch pin not pushed Below 1 Ω
      3-4 Switch pin not pushed 10 kΩ or higher
      1-2 Switch pin pushed 10 kΩ or higher
      3-4 Switch pin pushed Below 1 Ω
      Fig 1: Inspecting Stop Light Switch
      G05252156Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE STOP LIGHT SWITCH  (See ON-VEHICLE INSPECTION )

    OK: Go to Next Step 

  4. CHECK WIRE HARNESS (STOP LIGHT SWITCH - BATTERY) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      A40-2 - Body ground Always 10 to 14 V
      A40-3 - Body ground Engine switch on (IG) 10 to 14 V
    Fig 2: Identifying A40 Connector Terminals
    G05252155Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  5. CHECK ECM 
    1. Reconnect the stop light switch connector.
    2. Disconnect the A10 connector from the ECM.
    3. Turn the engine switch on (IG).
    4. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connection Brake Pedal Condition Specified Condition
      A10-36 (STP) - Body ground Depressed 10 to 14 V
      A10-36 (STP) - Body ground Released Below 1 V
      A10-35 (ST1-) - Body ground Depressed Below 1 V
      A10-35 (ST1-) - Body ground Released 10 to 14 V
    Fig 3: Identifying A10 Connector Terminals
    G05252202Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH - ECM) 

    OK: REPLACE ECM  (See REMOVAL )