TOYOTA SEQUOIA 2001 Service Repair Manual

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1259
1453 Author: Date:
2005 SEQUOIA (RM1146U)
9 Replace occupant classification ECU.
(a) Turn the ignition switch to the ON 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).
NEXT
10 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
11 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±1260
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1454 Author: Date:
2005 SEQUOIA (RM1146U)
DTC B1780 Occupant Classification Sensor Front LH
Circuit Malfunction
CIRCUIT DESCRIPTION
The occupant classification sensor front LH circuit consists of the occupant classification ECU and the occu-
pant classification sensor front LH.
DTC B1780 is recorded when a malfunction is detected in the occupant classification sensor front LH circuit.
DTC No.DTC Detecting ConditionTrouble Area
B1780

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 LH circuit for 2 seconds.

Occupant classification sensor front LH malfunction

Occupant classification ECU malfunction

Front seat assembly RH
(Occupant classification sensor front LH)

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 B1780 is output, perform troubleshooting
for the DTC.
DIDH5±01

H24040
Occupant
Classification ECU
O71
SGD1 O8
Occupant Classification
Sensor Front LH
O77
SIG1
O711
SVC1 SGD1
SIG1
SVC13
2
1O
G
V
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1261
1455 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

DI±1262
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1456 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 B1780 is not output.
HINT:
Codes other than DTC B1780 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
SGD1 Occupant
Classification
Sensor Front LH
CB DA
SIG1O7SVC1
Seat Wire No. 1
Occupant
Classification
ECU
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1263
1457 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 LH.
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 LH.
(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±1 (SGD1) ±
Body groundIgnition switch ONBelow 1 V
O7±7 (SIG1) ±
Body groundIgnition switch ONBelow 1 V
O7±11 (SVC1) ±
Body groundIgnition switch ONBelow 1 V
NG Repair or replace seat wire No. 1.
OK

H43111H43106H43699H23818
SGD1 C
B DA
SIG1O7
Service
Wire
Occupant
Classification
ECU
Occupant
Classification
Sensor Front LH
SVC1
Service Wire
SIG1 SVC1 SGD1
Seat Wire No. 1
O8
DI±1264
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1458 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 O8±1 (SVC1) and O8±3
(SGD1), O8±2 (SIG1) and O8±3 (SGD1) 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±11 (SVC1) ±
O7±1 (SGD1)AlwaysBelow 1 W
O7±7 (SIG1) ±
O7±1 (SGD1)AlwaysBelow 1 W
NG Repair or replace seat wire No. 1.
OK

H43111H43105H23817
SGD1 Occupant
Classification
Sensor Front LH
CB DA
SIG1O7SVC1
Seat Wire No. 1
Occupant
Classification
ECU
H43111H43105H23817
SGD1 Occupant
Classification
Sensor Front LH
CB DA
SIG1SVC1
O7 Seat Wire No. 1
Occupant
Classification
ECU
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1265
1459 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±7 (SIG1) ±
O7±1 (SGD1)Always1 MW or higher
O7±11 (SVC1) ±
O7±1 (SGD1)Always1 MW or higher
O7±7 (SIG1) ±
O7±11 (SVC1)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±1 (SGD1) ±
Body groundAlways1 MW or higher
O7±7 (SIG1) ±
Body groundAlways1 MW or higher
O7±11 (SVC1) ±
Body groundAlways1 MW or higher
NG Repair or replace seat wire No. 1.
OK

DI±1266
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1460 Author: Date:
2005 SEQUOIA (RM1146U)
7 Check DTC.
PREPARATION:
(a) Connect the connectors to the occupant classification ECU and the occupant classification sensor
front LH.
(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 B1780 is not output.
HINT:
Codes other than DTC B1780 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±1267
1461 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±1268
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1462 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 B1780 is not output.
HINT:
Codes other than DTC B1780 may be output at this time, but they are not related to this check.
NG Go to step 12.
OK
END