Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001C2DX
Model Year Start: 2019 Model: Avalon HV Prod Date Range: [04/2018 -           ]
Title: PARK ASSIST / MONITORING: INTELLIGENT CLEARANCE SONAR SYSTEM (for HV Model): C1A4B; Stop Light Relay Circuit; 2019 - 2022 MY Avalon HV [04/2018 -        ]

DTC

C1A4B

Stop Light Relay Circuit

DESCRIPTION

When a stop light relay circuit malfunction signal sent from the electronically controlled brake system is detected by the clearance warning ECU assembly, DTC C1A4B is stored.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1A4B

Stop Light Relay Circuit

Stop light relay circuit malfunction

Electronically controlled brake system

CAUTION / NOTICE / HINT

NOTICE:

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

    Click here 2019 - 2022 MY Avalon Avalon HV [04/2018 -        ]; INTRODUCTION: REPAIR INSTRUCTION: PRECAUTION

  • After replacing an ultrasonic sensor or the clearance warning ECU assembly, perform the necessary procedures (adjustment, calibration, initialization or registration).

    Click here 2019 - 2022 MY Avalon HV [04/2018 -        ]; PARK ASSIST / MONITORING: INTELLIGENT CLEARANCE SONAR SYSTEM (for HV Model): CALIBRATION

  • When DTC C1A4B is stored, there may be a malfunction in the lighting system. Inspect the lighting system before performing the following procedure.

    for HV Model with Cornering Light: Click here 2019 - 2021 MY Avalon HV [04/2018 - 08/2021]; LIGHTING (EXT): LIGHTING SYSTEM (for HV Model with Cornering Light): HOW TO PROCEED WITH TROUBLESHOOTING 2022 MY Avalon HV [08/2021 -        ]; LIGHTING (EXT): LIGHTING SYSTEM (for HV Model with Cornering Light): HOW TO PROCEED WITH TROUBLESHOOTING

    for HV Model without Cornering Light: Click here 2019 - 2021 MY Avalon HV [04/2018 - 08/2021]; LIGHTING (EXT): LIGHTING SYSTEM (for HV Model without Cornering Light): HOW TO PROCEED WITH TROUBLESHOOTING 2022 MY Avalon HV [08/2021 -        ]; LIGHTING (EXT): LIGHTING SYSTEM (for HV Model without Cornering Light): HOW TO PROCEED WITH TROUBLESHOOTING

PROCEDURE

1.

CHECK DTC OUTPUT

(a) Using the Techstream, check for DTCs according to the prompts on the screen.

HINT:

After turning the power switch from off to on (IG), wait 4 seconds or more before checking for DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes

(b) Clear the DTCs according to the screen on the Techstream.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Clear DTCs

(c) Recheck for DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes

HINT:

  • DTC C1A4B is stored when a malfunction signal sent from the electronically controlled brake system is detected.
  • If the malfunctioning part has been repaired or replaced before rechecking for DTCs, DTC C1A4B will not be output again.
  • If DTC C1A4B is output frequently, duplicate the conditions that cause the problem symptoms and perform troubleshooting again, even though the DTC was not output when rechecking for DTCs.

    Click here 2019 - 2022 MY Avalon Avalon HV [04/2018 -        ]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING

Result

Proceed to

DTC C1A4B is output

A

DTC C1A4B is not output

B
A

GO TO PRE-COLLISION SYSTEM 2019 - 2021 MY Avalon HV [04/2018 - 08/2021]; PRE-COLLISION: PRE-COLLISION SYSTEM (for HV Model): HOW TO PROCEED WITH TROUBLESHOOTING 2022 MY Avalon Avalon HV [08/2021 -        ]; PRE-COLLISION: PRE-COLLISION SYSTEM: HOW TO PROCEED WITH TROUBLESHOOTING

B

USE SIMULATION METHOD TO CHECK