Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001BE5K
Model Year Start: 2019 Model: Avalon HV Prod Date Range: [04/2018 - 08/2021]
Title: PRE-COLLISION: PRE-COLLISION SYSTEM (for HV Model): C1A4B; Stop Light Relay Circuit; 2019 - 2021 MY Avalon HV [04/2018 - 08/2021]

DTC

C1A4B

Stop Light Relay Circuit

DESCRIPTION

The skid control ECU (brake booster with master cylinder assembly) sends a stop light operation request signal to the stop light relay (stop light switch assembly). If the skid control ECU (brake booster with master cylinder 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:

  1. All of the following conditions are met:
    • 3 seconds have elapsed since the power switch was turned to on (IG).
    • The battery voltage is 10 V or more for 3 seconds or more.
  2. All of the following conditions are met for 1 second or more:
    • Communication between the driving support ECU assembly and skid control ECU (brake booster with master cylinder assembly) is normal.
    • The driving support ECU assembly receives a stop light relay circuit malfunction signal from the skid control ECU (brake booster with master cylinder 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.

Click here 2019 - 2022 MY Avalon HV [04/2018 -        ]; NETWORKING: CAN COMMUNICATION SYSTEM (for HV Model): HOW TO PROCEED WITH TROUBLESHOOTING

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.

Click here 2019 - 2022 MY Avalon HV [04/2018 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): HOW TO PROCEED WITH TROUBLESHOOTING

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