Last Modified: 11-20-2023 6.11:8.1.0 Doc ID: RM100000001KCS5
Model Year Start: 2020 Model: Camry Prod Date Range: [09/2019 -           ]
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: B1771; Passenger Side Buckle Switch Circuit Malfunction; 2020 - 2024 MY Camry [09/2019 -        ]

DTC

B1771

Passenger Side Buckle Switch Circuit Malfunction

DESCRIPTION

The front passenger side buckle switch circuit consists of the occupant detection ECU and front passenger side buckle switch (front seat inner belt assembly RH).

DTC B1771 is stored when a malfunction is detected in the front passenger side buckle switch circuit.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B1771

Passenger Side Buckle Switch Circuit Malfunction

  • The occupant detection ECU detects a line short, short to ground or B+, or an open in the front passenger side buckle switch circuit.
  • Front passenger side buckle switch malfunction
  • Occupant detection ECU malfunction
  • Front seat wire RH
  • Front passenger side buckle switch (Front seat inner belt assembly RH)
  • Occupant detection ECU

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

After turning the ignition 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 2020 MY Camry [09/2019 - 03/2020]; INTRODUCTION: REPAIR INSTRUCTION: PRECAUTION 2020 - 2024 MY Camry [03/2020 -        ]; INTRODUCTION: REPAIR INSTRUCTION: PRECAUTION

HINT:

  • When DTC B1650 is stored as a result of troubleshooting for the airbag system, check the DTCs stored in the occupant detection ECU. When DTC B1771 is output, perform troubleshooting for this DTC first.
  • If it is difficult to perform troubleshooting (wire harness inspection), remove the front passenger seat installation bolts to see under the seat cushion.
  • In the above case, lift and hold the seat so that it does not fall down. Hold the seat only as necessary because holding the seat for a long period of time may cause seat rail deformation.

PROCEDURE

1.

CHECK CONNECTORS

(a) Turn the ignition switch off.

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

(c) Check that the connectors are properly connected to the occupant detection ECU and front seat inner belt assembly RH.

OK:

The connectors are properly connected.

HINT:

If the connectors are not properly connected, reconnect the connectors and proceed to the next inspection.

(d) Disconnect the connectors from the occupant detection ECU and front seat inner belt assembly RH.

(e) Check that the terminals of the connectors are not deformed or damaged.

OK:

The terminals are not deformed or damaged.

NG

REPLACE FRONT SEAT WIRE RH

OK

2.

CHECK FRONT SEAT WIRE RH

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

*1

Front Seat Inner Belt Assembly RH

*2

Occupant Detection ECU

*3

Front Seat Wire RH

*4

Service Wire

*a

Front view of wire harness connector

(to Occupant Detection ECU)

*b

Front view of wire harness connector

(to Front Seat Inner Belt Assembly RH)

(b) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

a6-7 (BSW) - Body ground

Ignition switch ON

Below 1 V

a6-9 (BGND) - Body ground

Ignition switch ON

Below 1 V

(d) Turn the ignition switch off.

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

(f) Using a service wire, connect terminals 2 (BSW) and 1 (BGND) of connector C.

NOTICE:

Do not forcibly insert the service wire into the terminals of the connector when connecting the wire.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

a6-7 (BSW) - a6-9 (BGND)

Always

Below 1 Ω

(h) Disconnect the service wire from connector C.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

a6-7 (BSW) - a6-9 (BGND)

Always

1 MΩ or higher

a6-7 (BSW) - Body ground

Always

1 MΩ or higher

a6-9 (BGND) - Body ground

Always

1 MΩ or higher

NG

REPLACE FRONT SEAT WIRE RH

OK

3.

CHECK DTC

(a) Connect the connectors to the occupant detection ECU and front seat inner belt assembly RH.

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

(c) Turn the ignition switch to ON, and wait for at least 60 seconds.

(d) Clear the DTCs stored in the occupant detection ECU.

Body Electrical > Occupant Detection > Clear DTCs

(e) Clear the DTCs stored in the airbag sensor assembly.

Body Electrical > SRS Airbag > Clear DTCs

(f) Turn the ignition switch off.

(g) Turn the ignition switch to ON, and wait for at least 10 seconds.

(h) Check for DTCs.

Body Electrical > Occupant Detection > Trouble Codes

OK:

DTC B1771 is not output.

HINT:

Codes other than DTC B1771 may be output at this time, but they are not related to this check.

(i) Turn the ignition switch off.

OK

USE SIMULATION METHOD TO CHECK 2020 MY Camry [09/2019 - 03/2020]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING 2020 MY Camry [03/2020 - 10/2020]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING 2021 MY Camry [10/2020 - 08/2021]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING 2022 - 2024 MY Camry [08/2021 -        ]; INTRODUCTION: HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS: HOW TO PROCEED WITH TROUBLESHOOTING

NG

4.

CHECK FRONT SEAT INNER BELT ASSEMBLY RH

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

(b) Replace the front seat inner belt assembly RH with a known good one.

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HINT:

Perform the following inspection using known good parts from another vehicle if possible.

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

(d) Turn the ignition switch to ON, and wait for at least 60 seconds.

(e) Clear the DTCs stored in the occupant detection ECU.

Body Electrical > Occupant Detection > Clear DTCs

(f) Clear the DTCs stored in the airbag sensor assembly.

Body Electrical > SRS Airbag > Clear DTCs

(g) Turn the ignition switch off.

(h) Turn the ignition switch to ON, and wait for at least 10 seconds.

(i) Check for DTCs.

Body Electrical > Occupant Detection > Trouble Codes

OK:

DTC B1771 is not output.

HINT:

Codes other than DTC B1771 may be output at this time, but they are not related to this check.

(j) Turn the ignition switch off.

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

(l) Restore the front seat inner belt assembly RH that was installed for testing to its original location.

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OK

REPLACE FRONT SEAT INNER BELT ASSEMBLY RH 2020 MY Camry [09/2019 - 10/2020]; SEAT BELT: FRONT SEAT INNER BELT ASSEMBLY: REMOVAL 2021 - 2024 MY Camry [10/2020 -        ]; SEAT BELT: FRONT SEAT INNER BELT ASSEMBLY: REMOVAL

NG

5.

REPLACE OCCUPANT DETECTION ECU

(a) Turn the ignition switch off.

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

(c) Replace the occupant detection ECU with a new one.

Click here 2020 MY Camry [09/2019 - 10/2020]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION ECU: REMOVAL 2021 - 2024 MY Camry [10/2020 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION ECU: REMOVAL

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

NEXT

6.

PERFORM ZERO POINT CALIBRATION

(a) Using the Techstream, perform Zero Point Calibration.

Click here 2018 - 2024 MY Camry [06/2017 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: INITIALIZATION

NEXT

END