Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000VJRR
Model Year Start: 2016 Model: Sienna Prod Date Range: [12/2015 -           ]
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: B1771; Passenger Side Buckle Switch Circuit Malfunction; 2016 - 2020 MY Sienna [12/2015 -        ]

DTC

B1771

Passenger Side Buckle Switch Circuit Malfunction

DESCRIPTION

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

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

DTC Code

DTC Detection Condition

Trouble Area

B1771

One of following conditions is met:

  • Occupant classification ECU detects line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to +B signal in passenger side buckle switch circuit for 2 seconds
  • Passenger side buckle switch malfunction
  • Occupant classification ECU malfunction
  • Front seat wire RH
  • Front seat inner belt assembly RH (Passenger side buckle switch)
  • Occupant classification ECU

HINT:

  • When DTC B1650/32 is detected as a result of troubleshooting the airbag system, perform troubleshooting for DTC B1771 of the occupant classification system.
  • Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTC cannot be read.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

  • If troubleshooting (wire harness inspection) is difficult to perform, remove the front seat RH installation bolts to see the undersurface of the seat cushion.
  • In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may cause a problem, such as seat rail deformation. Hold the seat up only for as long as necessary.

PROCEDURE

1.

CHECK FOR DTC

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

(b) Clear the DTCs stored in the memory (See page 2016 - 2020 MY Sienna [12/2015 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR ).

HINT:

  • First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.
  • Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.

(c) Turn the ignition switch off.

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

(e) Check for DTCs (See page 2016 - 2020 MY Sienna [12/2015 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR ).

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.

OK

USE SIMULATION METHOD TO CHECK

NG

2.

CHECK CONNECTION OF CONNECTOR

(a) Turn the ignition switch off.

(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

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

OK:

Connectors are properly connected.

NG

CONNECT CONNECTORS PROPERLY

OK

3.

CHECK CONNECTOR

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

(b) Check that the connectors (on the occupant classification ECU side and front seat inner belt assembly RH side) are not damaged.

OK:

Connectors are not deformed or damaged.

NG

REPLACE FRONT SEAT WIRE RH

OK

4.

CHECK FRONT SEAT WIRE RH

Text in Illustration

*1

Front Seat Inner Belt Assembly RH

*2

Occupant Classification ECU

*3

Front Seat Wire RH

*4

Front view of wire harness connector

(to Occupant Classification ECU)

*5

Front view of wire harness connector

(to Front Seat Inner Belt Assembly RH)

*6

Connector B

*7

Connector C

*8

Service Wire

(a) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

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

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

X6-9 (BSW) - Body ground

Ignition switch ON

Below 1 V

X6-5 (BGND) - Body ground

(d) Turn the ignition switch off.

(e) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(f) Using a service wire, connect terminals 1 (RBE+) and 2 (RBE-) of connector C.

NOTICE:

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

X6-9 (BSW) - X6-5 (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

X6-9 (BSW) - Body ground

Always

1 MΩ or higher

X6-5 (BGND) - Body ground

X6-9 (BSW) - X6-5 (BGND)

NG

REPLACE FRONT SEAT WIRE RH

OK

5.

CHECK FOR DTC

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

(b) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

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

(d) Clear the DTCs stored in the memory (See page 2016 - 2020 MY Sienna [12/2015 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR ).

HINT:

  • First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.
  • Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.

(e) Turn the ignition switch off.

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

(g) Using the Techstream, check for DTCs of the occupant classification ECU (See page 2016 - 2020 MY Sienna [12/2015 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR ).

OK:

DTC B1771 is not output.

HINT:

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

OK

USE SIMULATION METHOD TO CHECK

NG

6.

REPLACE FRONT SEAT INNER BELT ASSEMBLY RH (PASSENGER SIDE BUCKLE SWITCH)

(a) Turn the ignition switch off.

(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(c) Replace the front seat inner belt assembly RH (See page 2016 - 2020 MY Sienna [12/2015 -        ]; SEAT BELT: FRONT SEAT INNER BELT ASSEMBLY: REMOVAL ).

HINT:

Perform the inspection using parts from a normal vehicle when possible.

(d) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

NEXT

7.

CHECK FOR DTC

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

(b) Clear the DTCs stored in the memory (See page 2016 - 2020 MY Sienna [12/2015 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR ).

HINT:

  • First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.
  • Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.

(c) Turn the ignition switch off.

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

(e) Using the Techstream, check for DTCs of the occupant classification ECU (See page 2016 - 2020 MY Sienna [12/2015 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR ).

OK:

DTC B1771 is not output.

HINT:

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

OK

END

NG

8.

REPLACE OCCUPANT CLASSIFICATION ECU

(a) Turn the ignition switch off.

(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(c) Replace the occupant classification ECU (See page 2016 - 2020 MY Sienna [12/2015 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION ECU: REMOVAL ).

HINT:

Perform the inspection using parts from a normal vehicle when possible.

(d) Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.

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

(f) Clear the DTCs stored in the memory (See page 2016 - 2020 MY Sienna [12/2015 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR ).

HINT:

If the DTCs are not cleared at this time, past DTCs will remain.

NEXT

9.

PERFORM ZERO POINT CALIBRATION

(a) Connect the Techstream to the DLC3.

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

(c) Using the Techstream, perform the zero point calibration (See page 2016 - 2020 MY Sienna [12/2015 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: INITIALIZATION ).

NEXT

10.

PERFORM SENSITIVITY CHECK

(a) Using the Techstream, perform the sensitivity check (See page 2016 - 2020 MY Sienna [12/2015 -        ]; SUPPLEMENTAL RESTRAINT SYSTEMS: OCCUPANT CLASSIFICATION SYSTEM: INITIALIZATION ).

Standard range:

27 to 33 kg (59.5 to 72.8 lb)

NEXT

END