Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM100000001AS3I
Model Year Start: 2019 Model: Avalon Prod Date Range: [04/2018 -           ]
Title: DOOR LOCK: POWER DOOR LOCK CONTROL SYSTEM (for Gasoline Model): B1243; GSW Terminal Circuit Malfunction; 2019 - 2022 MY Avalon [04/2018 -        ]

DTC

B1243

GSW Terminal Circuit Malfunction

DESCRIPTION

If the collision door lock release function does not operate normally, or an open or short in the GSW input circuit of the main body ECU (multiplex network body ECU) is detected, DTC B1243 will be stored.

HINT:

If DTC B1243 is stored, the automatic door lock function, and collision door lock release function will be prohibited.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B1243

GSW Terminal Circuit Malfunction

A malfunction occurs in the GSW input circuit of the main body ECU (multiplex network body ECU).
  • Main body ECU (multiplex network body ECU)
  • Airbag ECU assembly
  • Wire harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

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

  • Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

    Click here 2019 - 2020 MY Avalon [04/2018 - 08/2020]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): REGISTRATION 2021 - 2022 MY Avalon [08/2020 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): REGISTRATION

PROCEDURE

1.

CHECK DTC OUTPUT

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Main Body / Trouble Codes.

(e) Clear the DTCs.

Body Electrical > Main Body > Clear DTCs

(f) Recheck for DTCs.

Body Electrical > Main Body > Trouble Codes

OK:

DTC B1243 is not output.

OK

USE SIMULATION METHOD TO CHECK

NG

2.

CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) (GSW VOLTAGE)

(a) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

NOTICE:

Turning the engine switch on (IG) with the airbag ECU assembly connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

(b) Disconnect the G50 airbag ECU assembly connector.

(c) Connect the cable to the negative (-) battery terminal.

(d) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

G50-25 (GSW) - Body ground

Engine switch on (IG)

4.3 to 5.5 V

*a

Front view of wire harness connector

(to Airbag ECU Assembly)
NG

GO TO STEP 5

OK

3.

REPLACE AIR BAG ECU ASSEMBLY

(a) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(b) Replace the airbag ECU assembly.

Click here 2019 - 2020 MY Avalon Avalon HV [04/2018 - 08/2020]; SUPPLEMENTAL RESTRAINT SYSTEMS: CENTER AIRBAG SENSOR ASSEMBLY: REMOVAL 2021 MY Avalon Avalon HV [08/2020 - 08/2021]; SUPPLEMENTAL RESTRAINT SYSTEMS: CENTER AIRBAG SENSOR ASSEMBLY: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: CENTER AIRBAG SENSOR ASSEMBLY: REMOVAL

NEXT

4.

CHECK DTC OUTPUT

(a) Clear the DTCs.

Body Electrical > Main Body > Clear DTCs

(b) Recheck for DTCs.

Body Electrical > Main Body > Trouble Codes

OK:

DTC B1243 is not output.

OK

END (AIRBAG ECU ASSEMBLY WAS DEFECTIVE)
NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL

5.

CHECK HARNESS AND CONNECTOR (AIRBAG ECU ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(b) Disconnect the 4A instrument panel junction block assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G50-25 (GSW) - 4A-7

Always

Below 1 Ω

4A-7 or G50-25 (GSW) - Other terminals and body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

6.

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

(a) Remove the instrument panel junction block assembly.

Click here 2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL

(b) Remove the main body ECU (multiplex network body ECU).

*a

Component without harness connected

(Instrument Panel Junction Block Assembly)

-

-

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

MB-24 (GSW) - 4A-7

Always

Below 1 Ω
OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL

NG

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 2019 - 2021 MY Avalon Avalon HV [04/2018 - 08/2021]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL 2022 MY Avalon Avalon HV [08/2021 -        ]; POWER DISTRIBUTION: MAIN BODY ECU: REMOVAL