Toyota Sequoia (2005). Manual - part 374

H24040

Occupant
Classification ECU

O7

4

SGD4

O11
Occupant Classification 
Sensor Rear RH

O7

10

SIG4

O7

6

SVC4

SGD4

SIG4

SVC4

3

2

1

R–W

L–W

Y

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–1291

1485

WIRING DIAGRAM

DI–1292

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

1486

INSPECTION PROCEDURE

HINT:

If troubleshooting (wire harness inspection) is difficult to perform, remove the passenger seat installa-
tion bolts to see the under surface of 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 only as necessary.

1

Check DTC.

CHECK:
(a)

Turn the ignition switch to the ON position.

(b)

Clear the DTCs stored in memory (see page 

DI–1147

).

HINT:
First clear DTCs stored in the occupant classification ECU and then in the airbag sensor assembly.
(c)

Turn the ignition switch to the LOCK position.

(d)

Turn the ignition switch to the ON position.

(e)

Using the hand–held tester, check the DTCs of the occupant classification ECU (see page 

DI–1147

).

OK:

DTC B1783 is not output.

HINT:
Codes other than DTC B1783 may be output at this time, but they are not related to this check.

NG

Go to step 2.

OK

From the results of the above inspection, the malfunctioning part can now be considered normal.
To make sure of this, use the simulation method to check (see page 

DI–1137

).

H43111

H43105

H23817

Seat Wire No. 1

C

B

D

A

O7

Occupant
Classification
Sensor Rear RH

SVC4

SGD4

SIG4

Occupant
Classification
ECU

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

DI–1293

1487

2

Check connection of connectors.

PREPARATION:
(a)

Turn the ignition switch to the LOCK position.

(b)

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

CHECK:
Check that the connectors are properly connected to the occupant classification ECU and the occupant clas-
sification sensor rear RH.
OK:

The connectors are connected securely.

NG

Connect connectors, then go to step 1.

OK

3

Check seat wire No. 1 (short to B+).

PREPARATION:
(a)

Disconnect the connectors from the occupant classifica-
tion ECU and the occupant classification sensor rear RH.

(b)

Connect the negative (–) terminal cable to the battery.

CHECK:
(a)

Turn the ignition switch to the ON position.

(b)

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

OK:

Tester Connection

Condition

Specified Condition

O7–4 (SGD4) – 

Body ground

Ignition switch ON

Below 1 V

O7–6 (SVC4) – 

Body ground

Ignition switch ON

Below 1 V

O7–10 (SIG4) – 

Body ground

Ignition switch ON

Below 1 V

NG

Repair or replace seat wire No. 1.

OK

H43111

H43106

H43699

H23818

C

B

D

A

Service 
Wire

Occupant
Classification
Sensor Rear RH

Occupant
Classification
ECU

SVC4

SGD4

SIG4

SIG4

SGD4

SVC4

Service Wire

Seat Wire No. 1

O7

O11

DI–1294

–

DIAGNOSTICS

SUPPLEMENTAL RESTRAINT SYSTEM

1488

4

Check seat wire No. 1 (open).

PREPARATION:
(a)

Turn the ignition switch to the LOCK position.

(b)

Disconnect the negative (–) terminal cable from the bat-
tery, and wait for at least 90 seconds.

(c)

Using a service wire, connect O11–1 (SVC4) and O11–3
(SGD4), O11–2 (SIG4) and O11–3 (SGD4) of connector
”C”.

NOTICE:
Do not forcibly insert a service wire into the terminals of the
connector when connecting.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:

Tester Connection

Condition

Specified Condition

O7–6 (SVC4) – 

O7–4 (SGD4)

Always

Below 1 

Ω

O7–10 (SIG4) – 

O7–4 (SGD4)

Always

Below 1 

Ω

NG

Repair or replace seat wire No. 1.

OK