Last Modified: 09-10-2025 6.11:8.1.0 Doc ID: RM100000001AOP1
Model Year Start: 2019 Model: Avalon Prod Date Range: [04/2018 - 08/2021]
Title: CRUISE CONTROL: LANE DEPARTURE ALERT SYSTEM (w/ Steering Control) (for Gasoline Model): C1A73; Driving Support ECU Receive Data Malfunction; 2019 - 2021 MY Avalon [04/2018 - 08/2021]

DTC

C1A73

Driving Support ECU Receive Data Malfunction

DESCRIPTION

If a communication error between the driving support ECU assembly and another ECU is detected, DTC C1A73 is stored.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1A73

Driving Support ECU Receive Data Malfunction

2 seconds after the engine switch is turned on (IG), a communication error between the driving support ECU assembly and other ECUs is detected 5 seconds or more.
  • CAN communication system
  • Forward recognition camera
  • Pre-collision system

CAUTION / NOTICE / HINT

NOTICE:

  • When replacing the forward recognition camera, always replace it with a new one. If a forward recognition camera which was installed to another vehicle is used, the information stored in the forward recognition camera will not match the information from the vehicle. As a result, a DTC may be stored.
  • If the forward recognition camera has been replaced with a new one, be sure to perform forward recognition camera adjustment.

    Click here 2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; CRUISE CONTROL: FRONT CAMERA: ADJUSTMENT (SEQUENTIAL RECOGNITION)

  • The lane departure alert system (w/ steering control) 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 [04/2018 -        ]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): HOW TO PROCEED WITH TROUBLESHOOTING

PROCEDURE

PROCEDURE

1.

CHECK FOR DTCs

HINT:

The driving support ECU communicates with other ECUs via CAN communication. Confirm that the CAN communication system is functioning normally before proceeding.

(a) Check for DTCs.

Body Electrical > Pre-Collision 2 > Trouble Codes

Result

Proceed to

DTC U0100, U0125, U0126, U0129, U0155, U0235, U023A, U1002 and U1104 are not output

A

DTC U0100, U0125, U0126, U0129, U0155, U0235, U023A, U1002 or U1104 are output

B
B

GO TO PRE-COLLISION SYSTEM

A

2.

CHECK FOR DTCs

(a) Clear the DTCs.

Chassis > LKA/LDA > Clear DTCs

(b) Make sure that the DTC detection conditions are met.

HINT:

If the detection conditions are not met, the system cannot detect the malfunction.

(c) Check for DTCs.

Chassis > LKA/LDA > Trouble Codes

Result

Proceed to

DTC C1A73 is not output

A

DTC C1A73 is output

B
A

USE SIMULATION METHOD TO CHECK

B

REPLACE FORWARD RECOGNITION CAMERA