LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 2015 >> Prius Three >> Repair and Diagnosis (Single Page) >> Restraints >> Restraints Control Systems >> Pre-Collision System - (Diagnostic Codes & Circuit Tests) (Except Plug-In) >> Pre-Collision System >> DTC C1A4B: Stop Light Relay Circuit [08/2014 - ] >> Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC C1A4B: Stop Light Relay Circuit [08/2014 - ]: Description

The brake booster with master cylinder (skid control ECU) sends a stop light operation signal to the stop light control relay. When the brake booster with master cylinder (skid control ECU) detects a malfunction in the stop light circuit, the driving support ECU stores DTC C1A4B.

DTC No. DTC Detection Condition Trouble Area
C1A4B Either of the following conditions is met:
  • When the power switch is on (IG), the IG1 terminal voltage is between 11 and 14 V and the stop light illumination output signal (STPO) is output, the signal is not received at terminal STP2 for 0.3 seconds or more.
  • When the power switch is on (IG), the IG1 terminal voltage is between 11 and 14 V and the stop light illumination output signal (STPO) is not output, the signals received at terminals STP and STP2 are different for 0.3 seconds or more.
  • Lighting system
  • Electronically controlled brake system
  • Harness or connector
  • stop light control relay
  • Driving support ECU