DTC    C1A4B    Stop Light Relay Circuit

for Preparation Click here


DESCRIPTION

The stop light switch assembly sends 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 brake booster with master cylinder (skid control ECU).
  1. Lighting system
  2. Electronically controlled brake system
  3. CAN communication system
  4. Driving support ECU

INSPECTION PROCEDURE

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

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 BRAKE BOOSTER WITH MASTER CYLINDER

  1. Replace the brake booster with master cylinder (skid control ECU) (Click here) (for LHD).

  1. Replace the brake booster with master cylinder (skid control ECU) (Click here) (for RHD).


NEXT


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

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

  1. Clear the DTCs (Click here).

  1. Check for DTCs.

    OK:
    DTC U0122 is not output.



NG
GO TO CAN COMMUNICATION SYSTEM (Click here)
OK

REPLACE DRIVING SUPPORT ECU (Click here)