PRE-COLLISION SYSTEM, Diagnostic DTC:C1A4A

DTC Code DTC Name
C1A4A Skid Control Buzzer Circuit

DESCRIPTION

Based on pre-collision control, the driving support ECU assembly provides warnings to the driver. The driving support ECU assembly does this by sending a request signal to the millimeter wave radar sensor assembly to sound the skid control buzzer assembly.

When the millimeter wave radar sensor assembly detects a malfunction in the skid control buzzer assembly circuit, a malfunction signal is sent to the driving support ECU assembly, and this DTC is stored.

DTC No. Detection Item DTC Detection Condition Trouble Area
C1A4A Skid Control Buzzer Circuit While the power switch is on (IG), a skid control buzzer assembly circuit malfunction signal is received from the millimeter wave radar sensor assembly for 3 seconds or more.

  • Skid control buzzer assembly

  • Wire harness or connector

  • Millimeter wave radar sensor assembly

  • Driving support ECU assembly

WIRING DIAGRAM

A01I2O9E04

INSPECTION PROCEDURE

Note


  • When the millimeter wave radar sensor assembly is replaced with a new one, adjustment of the radar sensor beam axis must be performed Click here.

  • Before performing the inspection, check that DTC U0235, U1002 or U1104 is not output.

  • Inspect the fuses for circuits related to this system before performing the following procedure.

  • When replacing the driving support ECU assembly, always replace it with a new one. If a driving support ECU assembly which was installed to another vehicle is used, the information stored in the driving support ECU assembly will not match the information from the vehicle. As a result, a DTC may be stored.

PROCEDURE


  1. PERFORM ACTIVE TEST USING TECHSTREAM (PCS CRASH ALARM BUZZER, PCS APPROACH ALARM BUZZER)


    1. Connect the Techstream to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the Techstream on.

    4. Enter the following menus: Body Electrical / Pre-Collision 2 / Active Test.

    5. Perform Active Test according to the display on the Techstream.

      Pre-Collision 2
      Tester Display Test Part Control Range Diagnostic Note
      PCS Crash Alarm Buzzer Skid control buzzer assembly ON or OFF Buzzer can be heard
      PCS Approach Alarm Buzzer Skid control buzzer assembly ON or OFF Buzzer can be heard
      Result
      Result Proceed to
      Skid control buzzer assembly does not sound A
      Skid control buzzer assembly sounds B

    B

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    A

  2. INSPECT SKID CONTROL BUZZER ASSEMBLY


    1. Remove the skid control buzzer assembly Click here.

    2. Inspect the skid control buzzer assembly Click here.


    NG

    REPLACE SKID CONTROL BUZZER ASSEMBLY Click here

    OK

  3. CHECK TERMINAL VOLTAGE (POWER SOURCE OF SKID CONTROL BUZZER ASSEMBLY)


    1. A01I4EWE08
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control Buzzer Assembly)

      Disconnect the I184 skid control buzzer assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      I184-2 (IG1) - Body ground Power switch on (IG) 11 to 14 V
      I184-2 (IG1) - Body ground Power switch off Below 1 V

    3. Reconnect the I184 skid control buzzer assembly connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (SKID CONTROL BUZZER ASSEMBLY - MILLIMETER WAVE RADAR SENSOR ASSEMBLY)


    1. Disconnect the I184 skid control buzzer assembly connector.

    2. Disconnect the A86 millimeter wave radar sensor assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I184-1 (BZ) - A86-10 (BZ) Always Below 1 Ω
      I184-1 (BZ) or A86-10 (BZ) - Body ground Always 10 kΩ or higher

    4. Reconnect the A86 millimeter wave radar sensor assembly connector.

    5. Reconnect the I184 skid control buzzer assembly connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY


    1. Replace the millimeter wave radar sensor assembly with a new one Click here.


    NEXT

  6. ADJUST MILLIMETER WAVE RADAR SENSOR ASSEMBLY


    1. Perform millimeter wave radar sensor assembly adjustment Click here.


    NEXT

  7. CHECK DTC OUTPUT (PRE-COLLISION 2)


    1. Connect the Techstream to the DLC3.

    2. Turn the power switch on (IG).

    3. Clear the DTCs Click here.

    4. Make sure that the DTC detection conditions are met.

      Tech Tips

      If the detection conditions are not met, the system cannot detect the malfunction.

    5. Enter the following menus: Body Electrical / Pre-Collision 2 / Trouble Codes.

    6. Check for DTCs.

      OK
      DTC C1A4A is not output.

    NG

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    OK

    END (MILLIMETER WAVE RADAR SENSOR ASSEMBLY WAS DEFECTIVE)