PRE-COLLISION: PRE-COLLISION SYSTEM (for Gasoline Model): C1A4B; Stop Light Relay Circuit; 2019 - 2021 MY Avalon [04/2018

Last Modified: 08-21-2023	6.11:8.1.0	Doc ID: RM100000001AOQF
Model Year Start: 2019	Model: Avalon	Prod Date Range: [04/2018 - 08/2021]
Title: PRE-COLLISION: PRE-COLLISION SYSTEM (for Gasoline Model): C1A4B; Stop Light Relay Circuit; 2019 - 2021 MY Avalon [04/2018 - 08/2021]

DTC

C1A4B

Stop Light Relay Circuit

DESCRIPTION

The skid control ECU (brake actuator assembly) sends a stop light operation request signal to the stop light relay (stop light switch assembly). If the skid control ECU (brake actuator assembly) 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	Both of the following conditions are met: All of the following conditions are met: 3 seconds have elapsed since the engine switch was turned to on (IG). The battery voltage is 10 V or more for 3 seconds or more. All of the following conditions are met for 1 second or more: Communication between the driving support ECU assembly and skid control ECU (brake actuator assembly) is normal. The driving support ECU assembly receives a stop light relay circuit malfunction signal from the skid control ECU (brake actuator assembly).	Electronically controlled brake system

CAUTION / NOTICE / HINT

NOTICE:

The pre-collision system uses the CAN communication system. First, confirm that there are no malfunctions in the CAN communication system. Refer to How to Proceed with Troubleshooting.

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PROCEDURE

1.	GO TO ELECTRONICALLY CONTROLLED BRAKE SYSTEM

HINT:

If DTC C1A4B is output by the pre-collision system, perform troubleshooting for the electronically controlled brake system.

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END