DTC C1A4B: Stop Light Relay Circuit [08/2019 - ]: Description

The skid control ECU (master cylinder solenoid) sends a stop light operation request signal to the stop light relay (stop light switch assembly). If the skid control ECU (master cylinder solenoid) detects a malfunction in the stop light relay (stop light switch assembly) circuit, the driving support ECU assembly stores DTC C1A4B.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
C1A4B	Stop Light Relay Circuit	Diagnosis Condition: +BI1 and +BI2 terminal voltage is 8.9 V or higher Malfunction status: Either of the following occurs When STPO is ON and STP is OFF, STP2 is OFF continuously for 0.3 seconds or more When STPO is OFF and STP and STP2 input signal statuses differ continuously for 0.3 seconds or more	Vehicle stability control system

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1A4B

Stop Light Relay Circuit

Diagnosis Condition:

+BI1 and +BI2 terminal voltage is 8.9 V or higher

Malfunction status:
Either of the following occurs

When STPO is ON and STP is OFF, STP2 is OFF continuously for 0.3 seconds or more
When STPO is OFF and STP and STP2 input signal statuses differ continuously for 0.3 seconds or more

Vehicle stability control system