PRE-CRASH SAFETY SYSTEM, Diagnostic DTC:C1A4B

DTC Code DTC Name
C1A4B Stop Light Relay Circuit

DESCRIPTION

The stop light switch assembly outputs a brake pedal operation signal to the driving support ECU. Based on the signal, the driving support ECU cancels cruise control.

DTC No. DTC Detection Condition Trouble Area
C1A4B When the power switch is on (IG), a stop light relay malfunction signal is received from the skid control ECU assembly.

  • Lighting system

  • Electronically controlled brake system

  • CAN communication system

  • Driving support ECU

INSPECTION PROCEDURE

Tech Tips


  • When this DTC is output, malfunction in the electronically controlled brake system is suspected. Check if the electronically controlled brake system is functioning normally Click here.

  • This circuit uses CAN communication. Therefore, be sure to check that the CAN communication system is normal before performing inspection Click here.

PROCEDURE


  1. CHECK DTC OUTPUT (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)


    1. Check DTC for electronically controlled brake system Click here.

      OK
      Electronically controlled brake system DTC is not output.

    NG

    GO TO ELECTRONICALLY CONTROLLED BRAKE SYSTEM Click here

    OK

  2. REPLACE SKID CONTROL ECU ASSEMBLY


    1. Replace the skid control ECU assembly Click here.


    NEXT

  3. CHECK DTC OUTPUT (PRE-CRASH SAFETY SYSTEM)


    1. Using the intelligent tester, enter the following menus: Body / Pre-Crash 2 / DTC.

    2. Clear the DTCs Click here.

    3. Check for DTCs.

      OK
      DTC U0122 is not output.

    NG

    GO TO CAN COMMUNICATION SYSTEM Click here

    OK

    REPLACE DRIVING SUPPORT ECU Click here