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 engine switch is on (IG), a stop light relay malfunction signal is received from the skid control ECU.

  • Lighting system

  • Vehicle stability control system

  • CAN communication system

  • Driving support ECU

INSPECTION PROCEDURE

Note

When this DTC is output, malfunction in the lighting system is suspected. Check if the lighting system is functioning normally Click here.

PROCEDURE


  1. CHECK DTC OUTPUT (VEHICLE STABILITY CONTROL SYSTEM)


    1. Check DTC for vehicle stability control system Click here.

      OK
      Vehicle stability control system DTC is not output.

    NG

    GO TO VEHICLE STABILITY CONTROL SYSTEM Click here

    OK

  2. REPLACE BRAKE ACTUATOR (SKID CONTROL ECU)


    1. Replace the brake actuator 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