Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000VJF8
Model Year Start: 2016 Model: Sienna Prod Date Range: [12/2015 - 11/2017]
Title: NETWORKING: LIN COMMUNICATION SYSTEM: B124D; Lost Communication with AFS LIN; 2016 - 2017 MY Sienna [12/2015 - 11/2017]

DTC

B124D

Lost Communication with AFS LIN

DESCRIPTION

The DTC is stored when the main body ECU detects malfunctions in the LIN communication system.

DTC No.

DTC Detection Condition

Trouble Area

B124D

Malfunction in LIN communication system
  • Inner rear view mirror assembly
  • Harness or connector
  • AFS ECU (headlight swivel computer assembly)

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • First perform the communication function inspections in How to Proceed with Troubleshooting to confirm that there are no CAN communication malfunctions before troubleshooting this symptom.
  • When using the Techstream with the ignition switch off to troubleshoot: Connect the Techstream to the vehicle, and turn a courtesy switch on and off at 1.5 second intervals until communication between the Techstream and vehicle begins.
  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTC (See page 2016 - 2020 MY Sienna [12/2015 -        ]; NETWORKING: LIN COMMUNICATION SYSTEM: DTC CHECK / CLEAR ).

NEXT

2.

CHECK FOR DTC

(a) Check for DTCs (See page 2016 - 2020 MY Sienna [12/2015 -        ]; NETWORKING: LIN COMMUNICATION SYSTEM: DTC CHECK / CLEAR ).

Result

Result

Proceed to

DTC B124D is output

A

DTC B124D is not output

B
B

USE SIMULATION METHOD TO CHECK

A

3.

CHECK HARNESS AND CONNECTOR (AFS ECU (HEADLIGHT SWIVEL COMPUTER ASSEMBLY) - INNER REAR VIEW MIRROR ASSEMBLY)

(a) Disconnect the A45 AFS ECU (headlight swivel computer assembly) connector.

(b) Disconnect the T2 inner rear view mirror assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

A45-10 (SMR) - T2-12 (LIN)

Always

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

T2-12 (LIN) - Body ground

Always

10 kΩ or higher

Text in Illustration

*a

Front view of wire harness connector

(to AFS ECU (Headlight Swivel Computer Assembly))

*b

Front view of wire harness connector

(to Inner Rear View Mirror Assembly)
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

INSPECT AFS ECU (HEADLIGHT SWIVEL ECU ASSEMBLY)

(a) Reconnect the A45 AFS ECU (headlight swivel computer assembly) connector.

(b) Connect an oscilloscope to the T2 inner rear view mirror assembly connector.

(c) Check the waveform.

OK:

Tester Connection

Switch Condition

Specified Condition

T2-12 (LIN) - T2-3 (E)

Ignition switch ON

Correct waveform is as shown

Text in Illustration

*a

Front view of wire harness connector

(to Inner Rear View Mirror Assembly)
OK

REPLACE AFS ECU (HEADLIGHT SWIVEL ECU ASSEMBLY)

NG

REPLACE INNER REAR VIEW MIRROR ASSEMBLY