TOYOTA SEQUOIA 2001 Service Repair Manual

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1249
1443 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check battery.
CHECK:
Measure the voltage of the battery.
OK:
Voltage: 11 to 14 V
NG Replace battery.
OK
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 airbag sensor assembly and combination meter.
OK:
The connectors are connected securely.
NG Connect connectors, then go to step 1.
OK
3 Check combination meter.
PREPARATION:
(a) Disconnect the connectors from the airbag sensor assembly.
(b) Connect the negative (±) terminal cable to the battery, and wait for at least 2 seconds.
CHECK:
Turn the ignition switch to the ON position, check the operation of the SRS warning light.
OK:
The SRS warning light comes on (goes off 6 seconds after the ignition switch is turned to the
ON position).
NG Go to combination meter system
(see page DI±1610).
OK

H22564H23040I27704H23986
A Cowl Wire Combination
Meter
C5
A20
Airbag
Sensor
Assembly
B C D
C5±29LA
DI±1250
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1444 Author: Date:
2005 SEQUOIA (RM1146U)
4 Check cowl wire (airbag sensor assembly ± combination meter).
PREPARATION:
Disconnect the connector from the combination meter.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Tester ConnectionConditionSpecified Condition
A20±14 (LA) ± C5±29AlwaysBelow 1 W
A20±14 (LA) ±
Body groundAlways1 MW or higher
NG Repair or replace cowl wire.
OK
Replace airbag sensor assembly (see page RS±82).

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1251
1445 Author: Date:
2005 SEQUOIA (RM1146U)
DTC B1771 Passenger Side Buckle Switch Circuit
Malfunction
CIRCUIT DESCRIPTION
The passenger side buckle switch circuit consists of the occupant classification ECU and the front seat inner
belt RH.
DTC B1771 is recorded when a malfunction is detected in the passenger side buckle switch circuit.
Troubleshoot DTC B1771 first when the DTC B1771 and B1795 are output simultaneously.
DTC No.DTC Detecting ConditionTrouble Area
B1771

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 passen-
ger side buckle switch circuit for 2 seconds.

Passenger side buckle switch malfunction

Occupant classification ECU malfunction

Front seat inner belt 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 B1771 is output, perform troubleshooting
for the DTC.
DIDH4±01

H23244
Occupant Classification ECU
O6
O6 R B17
Buckle SW RH
L
129
5BSW
BGND DI±1252
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1446 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1253
1447 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 B1771 is not output.
HINT:
Codes other than DTC B1771 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).

H43103H43111H23819
Occupant
Classification ECU
BGND
BSW CB DA
Front Seat
Inner Belt RHO6
Seat Wire No. 1
DI±1254
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1448 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 front seat inner
belt 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 front seat inner belt 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
O6±9 (BSW) ±
Body groundIgnition switch ONBelow 1 V
O6±5 (BGND) ±
Body groundIgnition switch ONBelow 1 V
NG Repair or replace seat wire No. 1.
OK

H43104
H43111H43698H24039H24509
B
BGND Front Seat
Inner Belt RHC DA
BSW Service
Wire 1
O6 Occupant
Classification ECU
2
B17 Seat Wire No. 1(*1)
B17(*2)
1 2
*1: w/ Power Seat
*2: w/o Power Seat
Service Wire
H43103H43111H23819
Occupant
Classification ECU
BGND
BSW CB DA
Front Seat
Inner Belt RHO6 Seat Wire No. 1
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1255
1449 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 B17±1 and B17±2 of con-
nector 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
O6±9 (BSW) ±
O6±5 (BGND)AlwaysBelow 1 W
NG Repair or replace seat wire No. 1.
OK
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
O6±9 (BSW) ±
O6±5 (BGND)Always1 MW or higher
NG Repair or replace seat wire No. 1.
OK

H43103H43111H23819
Occupant
Classification ECU
BGND
BSW CB DA
Front Seat
Inner Belt RHO6
Seat Wire No. 1
DI±1256
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1450 Author: Date:
2005 SEQUOIA (RM1146U)
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
O6±9 (BSW) ±
Body groundAlways1 MW or higher
O6±5 (BGND) ±
Body groundAlways1 MW or higher
NG Repair or replace seat wire No. 1.
OK

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1257
1451 Author: Date:
2005 SEQUOIA (RM1146U)
7 Check DTC.
PREPARATION:
(a) Connect the connectors to the occupant classification ECU and the front seat inner belt 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 B1771 is not output.
HINT:
Codes other than DTC B1771 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).

DI±1258
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1452 Author: Date:
2005 SEQUOIA (RM1146U)
8 Replace front seat inner belt RH.
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.
(c) Replace the front seat inner belt RH (see page BO±112, BO±126).
HINT:
Perform the inspection using parts from a normal vehicle if possible.
(d) 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 B1771 is not output.
HINT:
Codes other than DTC B1771 may be output at this time, but they are not related to this check.
NG Go to step 9.
OK
END