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DTC C1A4B: Stop Light Relay Circuit [03/2014 - ]: 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 detects the operation of the brake pedal.

DTC No. DTC Detection Condition Trouble Area
C1A4B While the engine switch is on (IG).
When the skid control ECU detects a malfunction in the stop light relay circuit, it sends a malfunction signal to the driving support ECU via CAN communication and the driving support ECU stores this DTC.
  • CAN communication system
  • VSC system
  • Skid control ECU
  • Stop light switch assembly
  • Stop light control relay assembly
  • Driving support ECU