TOYOTA SEQUOIA 2001 Service Repair Manual

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1269
1463 Author: Date:
2005 SEQUOIA (RM1146U)
12 Replace front seat assembly RH.
(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.
(c) Replace the front seat assembly RH (see page BO±112, BO±126).
NEXT
13 Perform zero point calibration.
(a) Connect the negative (±) terminal cable to the battery.
(b) Connect the hand±held tester to the DLC3.
(c) Turn the ignition switch to the ON position.
(d) Using the hand±held tester, perform ºZero point calibrationº (see page DI±1128).
OK:
The ºCOMPLETEDº is displayed.
NEXT
14 Perform sensitivity check.
Using the hand±held tester, perform ºSensitivity checkº (see page DI±1128).
OK:
Standard value: 27 to 33 kg (59.52 to 72.75 lb)
NEXT
END

DI±1270
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1464 Author: Date:
2005 SEQUOIA (RM1146U)
DTC B1781 Occupant Classification Sensor Front RH
Circuit Malfunction
CIRCUIT DESCRIPTION
The occupant classification sensor front RH circuit consists of the occupant classification ECU and the occu-
pant classification sensor front RH.
DTC B1781 is recorded when a malfunction is detected in the occupant classification sensor front RH circuit.
DTC No.DTC Detecting ConditionTrouble Area
B1781

The occupant classification ECU 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 occu-
pant classification sensor front RH for 2 seconds.

Occupant classification sensor front RH malfunction

Occupant classification ECU malfunction

Front seat assembly RH
(Occupant classification sensor front RH)

Occupant classification ECU

Seat wire No. 1
HINT:
When DTC B1650/32 is detected as a result of troubleshooting for the supplemental restraint system, check
the DTCs stored in the occupant classification ECU. When DTC B1781 is output, perform troubleshooting
for the DTC.
DIDH6±01

H24040
Occupant
Classification ECU
O72
SGD2 O9
Occupant Classification
Sensor Front RH
O78
SIG2
O712
SVC2 SGD2
SIG2
SVC23
2
1B±Y
LG
P
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1271
1465 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

DI±1272
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1466 Author: Date:
2005 SEQUOIA (RM1146U)
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 B1781 is not output.
HINT:
Codes other than DTC B1781 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).

H43111H43105H23817
SGD2 Occupant
Classification
Sensor Front RHSeat Wire No. 1
CB DA
SIG2O7SVC2
Occupant
Classification
ECU
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1273
1467 Author: Date:
2005 SEQUOIA (RM1146U)
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 front 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 front 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 ConnectionConditionSpecified Condition
O7±2 (SGD2) ±
Body groundIgnition switch ONBelow 1 V
O7±8 (SIG2) ±
Body groundIgnition switch ONBelow 1 V
O7±12 (SVC2) ±
Body groundIgnition switch ONBelow 1 V
NG Repair or replace seat wire No. 1.
OK

H43111H43106H43699H23818
C
B DA
Occupant
Classification
Sensor Front RHOccupant
Classification
ECU
SGD2
SIG2 SVC2 Service Wire
Service Wire
SGD2
SIG2 SVC2
Seat Wire No. 1
O7
O9
DI±1274
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1468 Author: Date:
2005 SEQUOIA (RM1146U)
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 O9±1 (SVC2) and O9±3
(SGD2), O9±2 (SIG2) and O9±3 (SGD2) of connector
ºCº.
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 ConnectionConditionSpecified Condition
O7±12 (SVC2) ±
O7±2 (SGD2)AlwaysBelow 1 W
O7±8 (SIG2) ±
O7±2 (SGD2)AlwaysBelow 1 W
NG Repair or replace seat wire No. 1.
OK

H43111H43105H23817
SGD2 Occupant
Classification
Sensor Front RH
CB DA
SIG2SVC2
Occupant
Classification
ECU
Seat Wire No. 1
O7
H43111H43105H23817
SGD2 Occupant
Classification
Sensor Front RH
CB DA
SIG2SVC2
Occupant
Classification
ECU
Seat Wire No. 1
O7
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1275
1469 Author: Date:
2005 SEQUOIA (RM1146U)
5 Check seat wire No. 1 (short).
PREPARATION:
Disconnect the service wire from connector ºCº.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Tester ConnectionConditionSpecified Condition
O7±8 (SIG2) ±
O7±2 (SGD2)Always1 MW or higher
O7±12 (SVC2) ±
O7±2 (SGD2)Always1 MW or higher
O7±8 (SIG2) ±
O7±12 (SVC2)Always1 MW or higher
NG Repair or replace seat wire No. 1.
OK
6 Check seat wire No. 1 (short to ground).
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Tester ConnectionConditionSpecified Condition
O7±8 (SIG2) ±
Body groundAlways1 MW or higher
O7±12 (SVC2) ±
Body groundAlways1 MW or higher
O7±2 (SGD2) ±
Body groundAlways1 MW or higher
NG Repair or replace seat wire No. 1.
OK

DI±1276
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1470 Author: Date:
2005 SEQUOIA (RM1146U)
7 Check DTC.
PREPARATION:
(a) Connect the connectors to the occupant classification ECU and the occupant classification sensor
front RH.
(b) Connect the negative (±) terminal cable to the battery.
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 B1781 is not output.
HINT:
Codes other than DTC B1781 may be output at this time, but they are not related to this check.
NG Go to step 8.
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).

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1277
1471 Author: Date:
2005 SEQUOIA (RM1146U)
8 Replace occupant classification ECU.
(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.
(c) Replace the occupant classification ECU (see page RS±111).
HINT:
Perform the inspection using parts from a normal vehicle if possible.
NEXT
9 Perform zero point calibration.
(a) Connect the negative (±) terminal cable to the battery.
(b) Connect the hand±held tester to the DLC3.
(c) Turn the ignition switch to the ON position.
(d) Using the hand±held tester, perform ºZero point calibrationº (see page DI±1128).
OK:
The ºCOMPLETEDº is displayed.
NG Go to step 12.
OK
10 Perform sensitivity check.
Using the hand±held tester, perform ºSensitivity checkº (see page DI±1128).
OK:
Standard value: 27 to 33 kg (59.52 to 72.75 lb)
NG Go to step 12.
OK

DI±1278
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1472 Author: Date:
2005 SEQUOIA (RM1146U)
11 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 B1781 is not output.
HINT:
Codes other than DTC B1781 may be output at this time, but they are not related to this check.
NG Go to step 12.
OK
END