SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (w/ Occupant Classification System): B1656; Seat Belt Buckle Switch (LH); 2019 - 2020 MY RAV4 RAV4 HV [02/2019

Last Modified: 01-30-2024	6.11:8.1.0	Doc ID: RM100000001HIA8
Model Year Start: 2019	Model: RAV4	Prod Date Range: [02/2019 - 08/2020]
Title: SUPPLEMENTAL RESTRAINT SYSTEMS: AIRBAG SYSTEM (w/ Occupant Classification System): B1656; Seat Belt Buckle Switch (LH); 2019 - 2020 MY RAV4 RAV4 HV [02/2019 - 08/2020]

DTC

B1656

Seat Belt Buckle Switch (LH)

DESCRIPTION

The seat belt buckle switch LH circuit consists of the airbag ECU assembly and front seat inner belt assembly LH.

DTC B1656 is stored when a malfunction is detected in the seat belt buckle switch LH circuit.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Warning Indicate	Test Mode / Check Mode
B1656	Seat Belt Buckle Switch (LH)	One of the following conditions is met: The airbag ECU assembly detects a line short, short to ground or B+, or an open in the seat belt buckle switch LH circuit. A front seat inner belt assembly LH (seat belt buckle switch LH) malfunction. An airbag ECU assembly malfunction.	Floor wire Front seat inner belt assembly LH Airbag ECU assembly	Comes on	Not applicable

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal.
Click here
When disconnecting the cable from the negative (-) auxiliary battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected.
Click here
After replacing the airbag ECU assembly, refer to initialization.
Click here

PROCEDURE

1.	CHECK CONNECTION OF CONNECTORS

(a) Turn the ignition switch off.

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

Connectors are not properly connected

CONNECT CONNECTORS PROPERLY

Connectors are properly connected

2.	CHECK CONNECTORS

(a) Disconnect the connectors from the airbag ECU assembly and front seat inner belt assembly LH.

*1	Front Seat Inner Belt Assembly LH
*2	Airbag ECU Assembly
*3	Floor Wire

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

Connectors are deformed or damaged

REPLACE FLOOR WIRE

Connectors are not deformed or damaged

3.	CHECK FLOOR WIRE

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

*1	Front Seat Inner Belt Assembly LH
*2	Airbag ECU Assembly
*3	Floor Wire
*4	Service Wire
*a	Front view of wire harness connector (to Front Seat Inner Belt Assembly LH)
*b	Front view of wire harness connector (to Airbag ECU Assembly)

(b) Turn the ignition switch to ON.

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
N35-1 (LBE-) - Body ground	Ignition switch ON	Below 1 V
N35-2 (LBE+) - Body ground	Ignition switch ON	Below 1 V

(d) Turn the ignition switch off.

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

(f) Using a service wire, connect terminals 28 (LBE+) and 27 (LBE-) of connector B.

NOTICE:

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
N35-1 (LBE-) - N35-2 (LBE+)	Always	Below 1 Ω

(h) Disconnect the service wire from connector B.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
N35-1 (LBE-) - N35-2 (LBE+)	Always	1 MΩ or higher
N35-1 (LBE-) - Body ground	Always	1 MΩ or higher
N35-2 (LBE+) - Body ground	Always	1 MΩ or higher

REPLACE FLOOR WIRE

CHECK DTC

(a) Connect the connectors to the airbag ECU assembly and front seat inner belt assembly LH.

*1	Front Seat Inner Belt Assembly LH
*2	Airbag ECU Assembly

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

(d) Clear the DTCs stored in memory.

Click here

Body Electrical > SRS Airbag > Clear DTCs

(e) Turn the ignition switch off.

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

(g) Check for DTCs.

Click here

Body Electrical > SRS Airbag > Trouble Codes

HINT:

Codes other than DTC B1656 may be output at this time, but they are not related to this check.

DTC B1656 is not output

USE SIMULATION METHOD TO CHECK

DTC B1656 is output

5.	REPLACE FRONT SEAT INNER BELT ASSEMBLY LH

(a) Turn the ignition switch off.

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

for Manual Seat:

Click here

for Power Seat:

Click here

HINT:

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

CHECK DTC

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

*1	Front Seat Inner Belt Assembly LH
*2	Airbag ECU Assembly

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

Click here

Body Electrical > SRS Airbag > Clear DTCs

(d) Turn the ignition switch off.

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

(f) Check for DTCs.

Click here

Body Electrical > SRS Airbag > Trouble Codes

HINT:

Codes other than DTC B1656 may be output at this time, but they are not related to this check.

DTC B1656 is not output

END (FRONT SEAT INNER BELT ASSEMBLY LH WAS DEFECTIVE)

DTC B1656 is output

REPLACE AIRBAG ECU ASSEMBLY