Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM1000000018YBM
Model Year Start: 2018 Model: Sienna Prod Date Range: [11/2017 -           ]
Title: PRE-COLLISION: PRE-COLLISION SYSTEM: C1A50; Brake System Malfunction; 2018 - 2020 MY Sienna [11/2017 -        ]

DTC

C1A50

Brake System Malfunction

DESCRIPTION

When the pre-collision system is operating, the driving support ECU assembly sends brake control signals to the skid control ECU (brake actuator assembly).

If the driving support ECU assembly receives a vehicle stability control system malfunction signal from the skid control ECU (brake actuator assembly) via CAN communication, DTC C1A50 will be stored.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1A50

Brake System Malfunction

While the ignition switch is ON, the driving support ECU assembly receives a vehicle stability control system malfunction signal from the skid control ECU (brake actuator assembly) for 0.3 seconds or more.
  • Vehicle stability control system
  • Skid control ECU (Brake actuator assembly)
  • Driving support ECU assembly

CAUTION / NOTICE / HINT

NOTICE:

  • When replacing the driving support ECU assembly, always replace it with a new one. If a driving support ECU assembly which was installed to another vehicle is used, the information stored in the driving support ECU assembly will not match the information from the vehicle. As a result, a DTC may be stored.
  • 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 2018 - 2020 MY Sienna [11/2017 -        ]; NETWORKING: CAN COMMUNICATION SYSTEM: HOW TO PROCEED WITH TROUBLESHOOTING

PROCEDURE

1.

CHECK FOR DTCs (VEHICLE STABILITY CONTROL SYSTEM)

HINT:

Pre-collision system DTC C1A50 may be stored due to a malfunction in the vehicle stability control system. Therefore, it is necessary to check for and troubleshoot vehicle stability control system DTCs first.

(a) Check for DTCs.

Click here 2018 - 2020 MY Sienna [11/2017 -        ]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DTC CHECK / CLEAR

Result

Proceed to

Vehicle stability control system DTCs are not output

A

Vehicle stability control system DTCs are output

B
B

GO TO VEHICLE STABILITY CONTROL SYSTEM

A

2.

CHECK FOR DTCs (PRE-COLLISION SYSTEM)

(a) Clear the DTCs.

Click here 2018 - 2020 MY Sienna [11/2017 -        ]; PRE-COLLISION: PRE-COLLISION SYSTEM: DTC CHECK / CLEAR

(b) Perform the following procedure.

HINT:

If the following procedure is not performed, the previously output DTC cannot be detected.

  1. Turn the ignition switch to ON and wait 0.3 seconds or more.

(c) Check for DTCs.

Click here 2018 - 2020 MY Sienna [11/2017 -        ]; PRE-COLLISION: PRE-COLLISION SYSTEM: DTC CHECK / CLEAR

Result

Proceed to

DTC C1A50 is not output

A

DTC C1A50 is output

B
A

USE SIMULATION METHOD TO CHECK

B

3.

REPLACE DRIVING SUPPORT ECU ASSEMBLY

(a) Replace the driving support ECU assembly.

Click here 2018 - 2020 MY Sienna [11/2017 -        ]; CRUISE CONTROL: DRIVING SUPPORT ECU: REMOVAL

NEXT

4.

CHECK FOR DTCs (PRE-COLLISION SYSTEM)

(a) Clear the DTCs.

Click here 2018 - 2020 MY Sienna [11/2017 -        ]; PRE-COLLISION: PRE-COLLISION SYSTEM: DTC CHECK / CLEAR

(b) Perform the following procedure.

HINT:

If the following procedure is not performed, the previously output DTC cannot be detected.

  1. Turn the ignition switch to ON and wait 0.3 seconds or more.

(c) Check for DTCs.

Click here 2018 - 2020 MY Sienna [11/2017 -        ]; PRE-COLLISION: PRE-COLLISION SYSTEM: DTC CHECK / CLEAR

Result

Proceed to

DTC C1A50 is not output

A

DTC C1A50 is output

B
A

END (DRIVING SUPPORT ECU ASSEMBLY WAS DEFECTIVE)
B

REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)