Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Stop Light Relay Circuit (C1A4B)

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:

  • 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.
  • 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

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

NEXT

END

    Vehicle Information Not Obtained (C1A02)

    Front Radar Sensor (C1A10)

    See More:

    Toyota Avalon (XX50) 2019-2022 Service & Repair Manual > Brake Fluid(for Hv Model): Components
    COMPONENTS ILLUSTRATION *1 BRAKE MASTER CYLINDER RESERVOIR FILLER CAP ASSEMBLY - - ILLUSTRATION *1 FRONT DISC BRAKE BLEEDER PLUG *2 FRONT DISC BRAKE BLEEDER PLUG CAP *3 REAR DISC BRAKE BLEEDER PLUG *4 REAR DISC BRAKE BLEEDER PLUG CAP Tightening torque for "Major areas involving basic vehicle perform ...

    Toyota Avalon (XX50) 2019-2022 Owners Manual

    Toyota Avalon (XX50) 2019-2022 Service & Repair Manual

    © 2025 Copyright www.tavalon.net
    0.0198