TOYOTA SEQUOIA 2001 Service Repair Manual

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1339
1533 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±1340
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1534 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 B1793 is not output.
HINT:
Codes other than DTC B1793 may be output at this time, but they are not related to this check.
NG Go to step 12.
OK
END

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1341
1535 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±1342
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1536 Author: Date:
2005 SEQUOIA (RM1146U)
DTC B1794 Occupant Classification ECU Battery
Positive Line Open
CIRCUIT DESCRIPTION
This circuit consists of the occupant classification ECU and the power source circuit (battery, fuse, wire har-
ness).
DTC B1794 is recorded when a malfunction is detected in the occupant classification ECU or the power
source circuit.
HINT:
When DTC B1794 is output after switching the ignition switch LOCK±ON±LOCK 50 times in a row when a
malfunction occurs in the power source circuit for the occupant classification system, the DTC is output again
when a malfunction is detected even once after being cleared, unless the normal system code is input.
DTC No.DTC Detecting ConditionTrouble Area
B1794

The ignition switch is turned from LOCK to ON, hold for 10
seconds or more, and back to LOCK again 50 times in a
row when a malfunction occurs in the power source circuit
for the occupant classification system.

Occupant classification ECU malfunction
Battery

ECU±B Fuse

Floor wire

Seat wire No. 1

Occupant classification ECU
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 B1794 is output, perform troubleshooting
for the DTC.
DIDHF±01

H23999
Occupant
Classification ECU
O6 +B1
BL11
W±R
J49
O6IG 7
O6GND 3 W±R C J/C
I
J48 W±R 2
3D 1
3ASub J/B No. 3
W±R
W±R
W±R
W±B
W±B
BL16 BL12
B±O B±O
J45B J/C
I
J44 B±O 2
4C 2
4DSub J/B No. 4
B±O
Instrument Panel J/B
17
1E 2
1CIGN1
3
1C
2
1E3
1J7
1J I18
Ignition SW
IG2B±R
AM26
5
W±RW±R
Engine Room J/B
8
2C
1
2DECU±B Short Pin
1
2C AM2 F10
FL Block
54B
B
Battery
BK
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1343
1537 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

DI±1344
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1538 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 fuse.
CHECK:
Check the ECU±B fuse.
OK:
Resistance: Below 1 W
NG Replace fuse.
OK

H23821
O6
+BGND Occupant Classification ECU:
IG
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1345
1539 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check seat wire No. 1 (source voltage).
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) Disconnect the connector from the occupant classifica-
tion ECU.
(d) Connect the negative (±) terminal cable to the battery.
CHECK:
(a) Turn the ignition switch to the ON position.
(b) Measure the voltage and resistance according to the val-
ue(s) in the table below.
OK:
Tester ConnectionConditionSpecified Condition
O6±1 (+B) ± Body groundIgnition switch ON10 to 14 V
O6±3 (GND) ±
Body groundAlwaysBelow 1 W
O6±7 (IG) ± Body groundIgnition switch ON10 to 14 V
NG Repair or replace seat wire No. 1.
OK

DI±1346
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1540 Author: Date:
2005 SEQUOIA (RM1146U)
4 Check DTC.
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) Connect the connector to the occupant classification ECU.
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, and wait for at least 10 seconds.
(e) Using the hand±held tester, check the DTCs of the occupant classification ECU (see page DI±1147).
OK:
DTC B1794 is not output.
HINT:
Codes other than DTC B1794 may be output at this time, but they are not related to this check.
NG Go to step 5.
OK
From the results of the above inspection, the malfunctioning part can not be considered normal.
To make sure of this, use the simulation method to check (see page DI±1137).

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1347
1541 Author: Date:
2005 SEQUOIA (RM1146U)
5 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 is possible.
NEXT
6 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 the ºZero point calibrationº (see page DI±1128).
OK:
The ºCOMPLETEDº is displayed.
NEXT
7 Perform sensitivity check.
Using the hand±held tester, perform the ºSensitivity checkº (see page DI±1128).
OK:
Standard value: 27 to 33 kg (59.52 to 72.75 lb)
NEXT
END

DI±1348
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1542 Author: Date:
2005 SEQUOIA (RM1146U)
DTC B1795 Occupant Classification ECU Circuit
Malfunction
CIRCUIT DESCRIPTION
DTC B1795 is recorded when a malfunction is detected in the occupant classification ECU.
Troubleshoot DTC B1771 first when the DTC B1771 and B1795 are output simultaneously.
DTC No.DTC Detecting ConditionTrouble Area
B1795

Occupant classification ECU circuit malfunction

The occupant classification ECU receives a short circuit to
ground signal in the passenger side buckle switch circuit
for 2 seconds.

Occupant classification ECU malfunction

Occupant classification ECU

Front seat inner belt RH

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 B1795 is output, perform troubleshooting
for the DTC.
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, and wait for at least 10 seconds.
(b) Using the hand±held tester, check the DTCs of the occupant classification ECU (see page DI±1147).
RESULT:
A: DTC B1795 is output.
B: DTC B1771 and B1795 are output.
HINT:
Codes other than DTC B1771 and B1795 may be output at this time, but they are not related to this check.
B Go to DTC B1771 (see page DI±1251).
A
DIDHG±01