Toyota Tacoma (2015-2018) Service Manual: Occupant Classification System Malfunction (B1650/32)

DESCRIPTION

The occupant classification system circuit consists of the airbag sensor assembly and the occupant classification system.

When the airbag sensor assembly receives signals from the occupant detection ECU, it determines whether or not the instrument panel passenger without door airbag assembly, front seat airbag assembly RH and seat belt pretensioner RH should be operated.

DTC B1650/32 is set when a malfunction is detected in the occupant classification system circuit.

DTC No.	DTC Detecting Conditions	Trouble Areas
B1650/32	Occupant classification system malfunction The airbag sensor assembly receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the occupant classification system circuit for 2 seconds Airbag sensor assembly malfunction	Occupant classification system Airbag sensor assembly Floor wire No. 1 seat wire

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 (See page ).

PROCEDURE

1.	CHECK DTC (AIRBAG SENSOR ASSEMBLY)

(a) Turn the ignition switch to ON.

(b) Clear any DTCs stored in the memory (See page ).

(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 ).

OK:

DTC B1650/32 is not output.

HINT:

DTCs other than B1650/32 may be output at this time, but they are not related to this check.

Result

Result	Proceed to
NG	A
OK	B

B

USE SIMULATION METHOD TO CHECK

A

2.	CHECK DTC (OCCUPANT DETECTION ECU)

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

(b) Using the Techstream, check for DTCs of the occupant detection ECU (See page ).

OK:

DTC is not output.

NG

GO TO DTC CHART

OK

3.	CHECK CONNECTION OF CONNECTORS

(a) Turn the ignition switch off.

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

(c) Check that the connectors are properly connected to the airbag sensor assembly and the occupant detection ECU.

OK:

The connectors are properly connected.

NG

CONNECT CONNECTORS

OK

4.	CHECK CONNECTORS

(a) Check that the connectors (on the airbag sensor assembly side and occupant detection ECU side) are not damaged (See page ).

OK:

The connectors are not deformed or damaged.

NG

REPLACE WIRE HARNESS

OK

5.	CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (FOR OPEN)

(a) Disconnect the connectors from the airbag sensor assembly and the occupant detection ECU.

(b) Separate Seat :

Using a service wire, connect O5-8 (FSR+) and O5-4 (FSR-) of connector E.

NOTICE:

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A23-12 (FSR+) - A23-13 (FSR-)	Always	Below 1 Ω

Text in Illustration

*1	Occupant Detection ECU
*2	No. 1 Seat Wire
*3	Floor Wire
*4	Airbag Sensor Assembly
*5	Service Wire

NG

GO TO STEP 13

OK

6.	CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (FOR SHORT)

(a) Disconnect the service wire from connector E.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A23-12 (FSR+) - A23-13 (FSR-)	Always	1 MΩ or Higher

Text in Illustration

*1	Occupant Detection ECU
*2	Airbag Sensor Assembly

NG

GO TO STEP 14

OK

7.	CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (TO B+)

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

(b) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A23-12 (FSR+) - Body ground	Ignition switch ON	Below 1 V
A23-13 (FSR-) - Body ground	Ignition switch ON	Below 1 V

Text in Illustration

*1	Occupant Detection ECU
*2	Airbag Sensor Assembly

NG

GO TO STEP 15

OK

8.	CHECK OCCUPANT CLASSIFICATION SYSTEM CIRCUIT (TO GROUND)

(a) Turn the ignition switch off.

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

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A23-12 (FSR+) - Body ground	Always	1 MΩ or Higher
A23-13 (FSR-) - Body ground	Always	1 MΩ or Higher

Text in Illustration

*1	Occupant Detection ECU
*2	Airbag Sensor Assembly

NG

GO TO STEP 16

OK

9.	CHECK AIRBAG SENSOR ASSEMBLY

(a) Turn the ignition switch off.

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

(c) Replace the airbag sensor assembly (See page ).

HINT:

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

(d) Connect the connectors to the airbag sensor assembly.

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

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

(g) Clear any DTCs stored in the memory (See page ).

(h) Turn the ignition switch off.

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

(j) Check for DTCs (See page ).

Result

Result	Proceed to
DTC B1650/32 is output	A
DTC B1650/32 is not output	B

HINT:

DTCs other than B1650/32 may be output at this time, but they are not related to this check.

B

END

A

10.	REPLACE OCCUPANT DETECTION ECU

(a) Turn the ignition switch off.

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

(c) Replace the occupant detection ECU (See page ).

NEXT

11.	PERFORM ZERO POINT CALIBRATION

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

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Using the Techstream, perform the zero point calibration (See page ).

OK:

COMPLETED is displayed on the tester.

NEXT

12.	PERFORM SENSITIVITY CHECK

(a) Using the Techstream, perform the sensitivity check (See page ).

Standard Value:

27 to 33 kg (59.52 to 72.75 lb)

NEXT

END

13.	CHECK NO. 1 SEAT WIRE (FOR OPEN)

(a) Disconnect the No. 1 seat wire connector from the instrument panel wire.

HINT:

The service wire has already been inserted into connector E.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
BH1-5 (FSR+) - BH1-6 (FSR-)	Always	Below 1 Ω

Text in Illustration

*1	Occupant Detection ECU
*2	No. 1 Seat Wire
*3	Floor Wire
*4	Airbag Sensor Assembly
*5	Service Wire

OK

REPLACE FLOOR WIRE

NG

REPLACE NO. 1 SEAT WIRE

14.	CHECK NO. 1 SEAT WIRE (FOR SHORT)

(a) Disconnect the No. 1 seat wire connector from the instrument panel wire.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
BH1-5 (FSR+) - BH1-6 (FSR-)	Always	1 MΩ or Higher

Text in Illustration

*1	Occupant Detection ECU
*2	No. 1 Seat Wire
*3	Floor Wire
*4	Airbag Sensor Assembly

OK

REPLACE FLOOR WIRE

NG

REPLACE NO. 1 SEAT WIRE

15.	CHECK NO. 1 SEAT WIRE (TO B+)

(a) Disconnect the No. 1 seat wire connector from the instrument panel wire.

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

(c) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
BH1-5 (FSR+) - Body ground	Ignition switch ON	Below 1 V
BH1-6 (FSR-) - Body ground	Ignition switch ON	Below 1 V

Text in Illustration

*1	Occupant Detection ECU
*2	No. 1 Seat Wire
*3	Floor Wire
*4	Airbag Sensor Assembly

OK

REPLACE FLOOR WIRE

NG

REPLACE NO. 1 SEAT WIRE

16.	CHECK NO. 1 SEAT WIRE (TO GROUND)

(a) Disconnect the No. 1 seat wire connector from the instrument panel wire.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
BH1-5 (FSR+) - Body ground	Always	1 MΩ or Higher
BH1-6 (FSR-) - Body ground	Always	1 MΩ or Higher

Text in Illustration

*1	Occupant Detection ECU
*2	No. 1 Seat Wire
*3	Floor Wire
*4	Airbag Sensor Assembly

OK

REPLACE FLOOR WIRE

NG

REPLACE NO. 1 SEAT WIRE