sensor TOYOTA SEQUOIA 2001 Service Repair Manual

DI±1310
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1504 Author: Date:
2005 SEQUOIA (RM1146U)
DTC B1787 Occupant Classification Sensor Rear LH
Collision Detection
CIRCUIT DESCRIPTION
DTC B1787 is output when the occupant classification ECU receives a collision detection signal sent by the
occupant classification sensor rear LH if an accident occurs.
DTC B1787 is also output when the front seat assembly RH is subjected to a strong impact, even if an actual
accident does not occur.
However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle is
not in a collision, DTC B1787 can be cleared by ºZero point calibrationº and ºSensitivity checkº.
Therefore, if DTC B1787 is output, first perform ºZero point calibrationº and ºSensitivity checkº.
DTC No.DTC Detecting ConditionTrouble Area
B1787

Front seat assembly RH malfunction

Occupant classification ECU malfunction

Occupant classification sensor rear LH detects heavy
load.
Front seat assembly RH
(Occupant classification sensor rear LH)

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 B1787 is output, perform troubleshooting
for the DTC.
WIRING DIAGRAM
See page DI±1280.
INSPECTION PROCEDURE
1 Perform zero point calibration.
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Using the hand±held tester, perform ºZero point calibrationº (see page DI±1147).
OK:
The ºCOMPLETEDº is displayed.
NG Go to step 4.
OK
DIDHB±01

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1311
1505 Author: Date:
2005 SEQUOIA (RM1146U)
2 Perform sensitivity check.
Using the hand±held tester, perform ºSensitivity checkº (see page DI±1147).
OK:
Standard value: 27 to 33 kg (59.52 to 72.75 lb)
NG Go to step 4.
OK
3 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 B1787 is not output.
HINT:
Codes other than DTC B1787 may be output at this time, but they are not related to this check.
NG Go to step 4.
OK
END

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1313
1507 Author: Date:
2005 SEQUOIA (RM1146U)
7 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 B1787 is not output.
HINT:
Codes other than DTC B1787 may be output at this time, but they are not related to this check.
NG Go to step 8.
OK
END

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1315
1509 Author: Date:
2005 SEQUOIA (RM1146U)
DTC B1788 Occupant Classification Sensor Rear RH
Collision Detection
CIRCUIT DESCRIPTION
DTC B1788 is output when the occupant classification ECU receives a collision detection signal sent by the
occupant classification sensor rear RH if an accident occurs.
DTC B1788 is also output when the front seat assembly RH is subjected to a strong impact, even if an actual
accident does not occur.
However, when the occupant classification ECU outputs a collision detection signal, even if the vehicle is
not in a collision, DTC B1788 can be cleared by ºZero point calibrationº and ºSensitivity checkº.
Therefore, if DTC B1788 is output, first perform ºZero point calibrationº and ºSensitivity checkº.
DTC No.DTC Detecting ConditionTrouble Area
B1788

Front seat assembly RH malfunction

Occupant classification ECU malfunction

Occupant classification sensor rear RH detects heavy
load.
Front seat assembly RH
(Occupant classification sensor rear RH)

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 B1788 is output, perform troubleshooting
for the DTC.
WIRING DIAGRAM
See page DI±1290.
INSPECTION PROCEDURE
1 Perform zero point calibration.
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Using the hand±held tester, perform ºZero point calibrationº (see page DI±1128).
OK:
The ºCOMPLETEDº is displayed.
NG Go to step 4.
OK
DIDHC±01

DI±1316
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1510 Author: Date:
2005 SEQUOIA (RM1146U)
2 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 4.
OK
3 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 B1788 is not output.
HINT:
Codes other than DTC B1788 may be output at this time, but they are not related to this check.
NG Go to step 4.
OK
END

DI±1318
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1512 Author: Date:
2005 SEQUOIA (RM1146U)
7 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 B1788 is not output.
HINT:
Codes other than DTC B1788 may be output at this time, but they are not related to this check.
NG Go to step 8.
OK
END

DI±1320
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1514 Author: Date:
2005 SEQUOIA (RM1146U)
DTC B1790 Airbag Sensor Assembly Communication
Circuit Malfunction
CIRCUIT DESCRIPTION
The airbag sensor assembly communication circuit consists of the occupant classification ECU and the air-
bag sensor assembly.
DTC B1790 is recorded when a malfunction is detected in the airbag sensor assembly communication cir-
cuit.
DTC No.DTC Detecting ConditionTrouble Area
B1790

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 airbag
sensor assembly communication circuit for 2 seconds.

Airbag sensor assembly malfunction

Occupant classification ECU malfunction

Occupant classification ECU

Airbag sensor assembly

Floor wire

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 B1790 is output, perform troubleshooting
for the DTC.
DIDHD±01

H02750
O6
Occupant Classification ECU
FSR+
BL13
WW
A2116Airbag Sensor Assembly
A2124
B B
BL15
FSR±FSR+
FSR± 8
4
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1321
1515 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

DI±1322
± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1516 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 B1790 is not output.
HINT:
Codes other than DTC B1790 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).

± DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI±1323
1517 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 airbag sensor
assembly.
OK:
The connectors are connected securely.
NG Connect connectors, then go to step 1.
OK
3 Prepare for inspection.
PREPARATION:
CAUTION:
Be sure to perform the following procedures before troubleshooting to avoid unexpected airbag de-
ployment.
(a) Disconnect the connectors from the airbag sensor assembly.
(b) Disconnect the connectors from the steering wheel pad.
(c) Disconnect the connectors from the front passenger airbag assembly.
(d) w/ Side and curtain shield airbag:
Disconnect the connectors from the side airbag assembly LH and RH.
(e) w/ Side and curtain shield airbag:
Disconnect the connectors from the curtain shield airbag assembly LH and RH.
(f) Disconnect the connectors from the front seat outer belt LH and RH.
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