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Home >> Lexus >> 2017 >> GS F >> Repair and Diagnosis >> Restraints >> Restraints Control Systems >> Pre-Collision System - Diagnostic Codes And Circuit Tests >> Pre-Collision System >> DTC C1A4A: Skid Control Buzzer Circuit [10/2015 - ] >> Procedure

DTC C1A4A: Skid Control Buzzer Circuit [10/2015 - ]: Procedure

  1. CHECK FOR DTCs (PRE-COLLISION SYSTEM) 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [10/2015 - ]

      Body Electrical > Pre-Collision 2 > Clear DTCs 

    2. Perform the Active Test according to the display on the Techstream.
      NOTE:

      Perform the Active Test for 1 second or more.

      HINT: 

      Performing the Active Test for 1 second or more causes DTC 1A4A to be stored if the DTC detection conditions are met.

      Body Electrical > Pre-Collision 2 > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      PCS Crash Alarm Buzzer Skid control buzzer ON / OFF Test possible with engine switch on (IG), vehicle stopped

      Body Electrical > Pre-Collision 2 > Active Test 

      Tester Display
      PCS Crash Alarm Buzzer
    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [10/2015 - ]

      Body Electrical > Pre-Collision 2 > Trouble Codes 

      Result

      Result Proceed to
      DTC C1A4A is not output A
      DTC C1A4A is output B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2015 - 09/2016]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2016 - 09/2017]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2017 - ] 

    Result: 

    B 

    See step  2

  2. CHECK TERMINAL VOLTAGE 
    1. Disconnect the skid control buzzer connector.
      GTY652586Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Skid Control Buzzer)
    2. Measure the voltage according to the value (s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      K1-2 (IG1) - Body ground Engine switch on (IG) 11 to 14 V
      Engine switch off Below 1 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL BUZZER - BATTERY) 

    Result: 

    OK 

    See step  3

  3. CHECK SKID CONTROL BUZZER (SKID CONTROL BUZZER - DRIVING SUPPORT ECU ASSEMBLY) 
    1. Disconnect the K1 skid control buzzer connector.
    2. Disconnect the K4 driving support ECU assembly connector.
    3. Measure the resistance according to the value (s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      K1-1 (BZ) - K4-3 (BZ) Always Below 1 Ω
      K1-1 (BZ) or K4-3 (BZ) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    See step  6

    Result: 

    NG 

    See step  4

  4. REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL BUZZER - DRIVING SUPPORT ECU ASSEMBLY) 
    1. Repair or replace the harness or connector.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  5

  5. CHECK FOR DTCs (PRE-COLLISION SYSTEM) 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [10/2015 - ]

      Body Electrical > Pre-Collision 2 > Clear DTCs 

    2. Perform the Active Test according to the display on the Techstream.
      NOTE:

      Perform the Active Test for 1 second or more.

      HINT: 

      Performing the Active Test for 1 second or more causes DTC 1A4A to be stored if the DTC detection conditions are met.

      Body Electrical > Pre-Collision 2 > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      PCS Crash Alarm Buzzer Skid control buzzer ON / OFF Test possible with engine switch on (IG), vehicle stopped

      Body Electrical > Pre-Collision 2 > Active Test 

      Tester Display
      PCS Crash Alarm Buzzer
    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [10/2015 - ]

      Body Electrical > Pre-Collision 2 > Trouble Codes 

      Result

      Result Proceed to
      DTC C1A4A is not output A
      DTC C1A4A is output B

    Result: 

    A 

    END 

    Result: 

    B 

    See step  6

  6. INSPECT SKID CONTROL BUZZER (CONFIRM BUZZER OPERATION) 
    1. Turn the engine switch on (IG).
    2. Check if the skid control buzzer is sounding.

      Result

      Result Proceed to
      The skid control buzzer does not sound when the engine switch is on (IG) A
      The skid control buzzer sounds continuously when the engine switch is on (IG) B

    Result: 

    B 

    See step  8

    Result: 

    A 

    See step  7

  7. INSPECT SKID CONTROL BUZZER ASSEMBLY (UNIT INSPECTION) 
    1. Remove the skid control buzzer.

      Refer to REMOVAL [10/2015 - ]

    2. Inspect the skid control buzzer.

      Refer to INSPECTION [10/2015 - ]

      Result

      Result Proceed to
      Skid control buzzer is abnormal A
      Skid control buzzer is normal B

    Result: 

    B 

    See step  6

    Result: 

    A 

    See step  8

  8. REPLACE SKID CONTROL BUZZER ASSEMBLY 
    1. Replace the skid control buzzer.

      Refer to DRIVING SUPPORT BUZZER

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  9

  9. CHECK FOR DTCs (PRE-COLLISION SYSTEM) 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [10/2015 - ]

      Body Electrical > Pre-Collision 2 > Clear DTCs 

    2. Perform the Active Test according to the display on the Techstream.
      NOTE:

      Perform the Active Test for 1 second or more.

      HINT: 

      Performing the Active Test for 1 second or more causes DTC 1A4A to be stored if the DTC detection conditions are met.

      Body Electrical > Pre-Collision 2 > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      PCS Crash Alarm Buzzer Skid control buzzer ON / OFF Test possible with engine switch on (IG), vehicle stopped

      Body Electrical > Pre-Collision 2 > Active Test 

      Tester Display
      PCS Crash Alarm Buzzer
    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [10/2015 - ]

      Body Electrical > Pre-Collision 2 > Trouble Codes 

      Result

      Result Proceed to
      DTC C1A4A is not output A
      DTC C1A4A is output B

    Result: 

    A 

    END 

    Result: 

    B 

    REPLACE DRIVING SUPPORT ECU ASSEMBLY. Refer to  REMOVAL [10/2015 - 09/2017]  , or refer to  REMOVAL [09/2017 - ] 

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