Page 1057 of 2572

05-1484
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1674 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC B1786 OCCUPANT CLASSIFICATION SENSOR
FRONT RH COLLISION DETECTION
CIRCUIT DESCRIPTION
DTC B1786 is output when the occupant classification ECU receives a collision detection signal sent by the
occupant classification sensor front RH if an accident occurs.
DTC B1786 is also output when the seat adjuster frame assy 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 B1786 can be cleared by ºZero point calibrationº and ºSensitivity checkº.
Therefore, if DTC B1786 is output, first perform ºZero point calibrationº and ºSensitivity checkº.
DTC No.DTC Detecting ConditionTrouble Area
B1786
Seat adjuster frame assy malfunction
Occupant classification ECU malfunction
Occupant classification sensor front RH sensed large loadOccupant classification ECU
Seat adjuster frame assy
(Occupant classification sensor front RH)
HINT:
When DTC B1150/23 is detected as a result of troubleshooting for the supplemental restraint system,
perform troubleshooting for DTC B1786 of the classification system.
Use the hand-held tester to check the DTC of the occupant classification ECU, otherwise the DTC
cannot be read.
WIRING DIAGRAM
see page 05-1460.
INSPECTION PROCEDURE
1 PERFORM ZERO POINT CALIBRATION
(a) Using the hand-held tester, perform ºZero point calibrationº (see page 05-1203).
OK:
The ºCOMPLETEDº is displayed.
NG Go to step 4
OK
2 PERFORM SENSITIVITY CHECK
(a) Using the hand-held tester, perform ºSensitivity checkº (see page 05-1203).
Standard value: 27 to 33 kg (59.52 to 72.75 lb)
NG Go to step 4
OK
05IWW-01
Page 1058 of 2572

- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
05-1485
1675 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
3 CHECK DTC
(a) Turn the ignition switch to the ON position.
(b) Clear the DTCs stored in airbag sensor assy center memory (see page 05-1215).
(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 (see page 05-1215).
OK:
DTC B1786 is not output.
HINT:
Codes other than code B1786 may be output at this time, but they are not related to this check.
NG Go to step 4
OK
END
4 REPLACE SEAT ADJUSTER FRAME ASSY
(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 seat adjuster frame assy (see page 72-1 1, 72-19).
HINT:
Perform the inspection using parts from a normal vehicle when possible.
5 PERFORM ZERO POINT CALIBRATION
(a) Using the hand-held tester, perform ºZero point calibrationº (see page 05-1203).
OK:
The ºCOMPLETEDº is displayed.
NG Go to step 8
OK
6 PERFORM SENSITIVITY CHECK
(a) Using the hand-held tester, perform ºSensitivity checkº (see page 05-1203).
Standard value: 27 to 33 kg (59.52 to 72.75 lb)
NG Go to step 8
OK
Page 1059 of 2572

05-1486
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1676 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
7 CHECK DTC
(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.
(c) Turn the ignition switch to the ON position.
(d) Clear the DTCs stored in memory (see page 05-1215).
HINT:
First clear DTCs stored in the occupant classification ECU memory and then in the airbag sensor assy
center memory.
Use the hand-held tester to clear the DTC of the occupant classification ECU, otherwise the DTC can-
not be cleared.
(e) Turn the ignition switch to the LOCK position.
(f) Turn the ignition switch to the ON position.
(g) Using the hand-held tester, check the DTCs (see page 05-1215).
OK:
DTC B1786 is not output.
HINT:
Codes other than code B1786 may be output at this time, but they are not related to this check.
NG Go to step 8
OK
END
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 60-64).
9 PERFORM ZERO POINT CALIBRATION
(a) Using the hand-held tester, perform ºZero point calibrationº (see page 05-1203).
OK:
The ºCOMPLETEDº is displayed.
10 PERFORM SENSITIVITY CHECK
(a) Using the hand-held tester, perform ºSensitivity checkº (see page 05-1203).
Standard value: 27 to 33 kg (59.52 to 72.75 lb)
END
Page 1060 of 2572

- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
05-1487
1677 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
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 seat adjuster frame assy 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
Seat adjuster frame assy malfunction
Occupant classification ECU malfunction
Occupant classification sensor rear LH sensed large loadOccupant classification ECU
Seat adjuster frame assy
(Occupant classification sensor rear LH)
HINT:
When DTC B1150/23 is detected as a result of troubleshooting for the supplemental restraint system,
perform troubleshooting for DTC B1787 of the classification system.
Use the hand-held tester to check the DTC of the occupant classification ECU, otherwise the DTC
cannot be read.
WIRING DIAGRAM
see page 05-1467.
INSPECTION PROCEDURE
1 PERFORM ZERO POINT CALIBRATION
(a) Using the hand-held tester, perform ºZero point calibrationº (see page 05-1203).
OK:
The ºCOMPLETEDº is displayed.
NG Go to step 4
OK
2 PERFORM SENSITIVITY CHECK
(a) Using the hand-held tester, perform ºSensitivity checkº (see page 05-1203).
Standard value: 27 to 33 kg (59.52 to 72.75 lb)
NG Go to step 4
OK
05IWX-01
Page 1061 of 2572

05-1488
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1678 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
3 CHECK DTC
(a) Turn the ignition switch to the ON position.
(b) Clear the DTCs stored in airbag sensor assy center memory (see page 05-1215).
(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 (see page 05-1215).
OK:
DTC B1787 is not output.
HINT:
Codes other than code B1787 may be output at this time, but they are not related to this check.
NG Go to step 4
OK
END
4 REPLACE SEAT ADJUSTER FRAME ASSY
(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 seat adjuster frame assy (see page 72-1 1, 72-19).
HINT:
Perform the inspection using parts from a normal vehicle when possible.
5 PERFORM ZERO POINT CALIBRATION
(a) Using the hand-held tester, perform ºZero point calibrationº (see page 05-1203).
OK:
The ºCOMPLETEDº is displayed.
NG Go to step 8
OK
6 PERFORM SENSITIVITY CHECK
(a) Using the hand-held tester, perform ºSensitivity checkº (see page 05-1203).
Standard value: 27 to 33 kg (59.52 to 72.75 lb)
NG Go to step 8
OK
Page 1062 of 2572

- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
05-1489
1679 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
7 CHECK DTC
(a) Connect the connectors to the occupant classification ECU and the occupant classification sensor rear
LH.
(b) Connect the negative (-) terminal cable to the battery.
(c) Turn the ignition switch to the ON position.
(d) Clear the DTCs stored in memory (see page 05-1215).
HINT:
First clear DTCs stored in the occupant classification ECU memory and then in the airbag sensor assy
center memory.
Use the hand-held tester to clear the DTC of the occupant classification ECU, otherwise the DTC can-
not be cleared.
(e) Turn the ignition switch to the LOCK position.
(f) Turn the ignition switch to the ON position.
(g) Using the hand-held tester, check the DTCs (see page 05-1215).
OK:
DTC B1787 is not output.
HINT:
Codes other than code B1787 may be output at this time, but they are not related to this check.
NG Go to step 8
OK
END
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 60-64).
9 PERFORM ZERO POINT CALIBRATION
(a) Using the hand-held tester, perform ºZero point calibrationº (see page 05-1203).
OK:
The ºCOMPLETEDº is displayed.
10 PERFORM SENSITIVITY CHECK
(a) Using the hand-held tester, perform ºSensitivity checkº (see page 05-1203).
Standard value: 27 to 33 kg (59.52 to 72.75 lb)
END
Page 1063 of 2572

05-1490
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1680 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
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 seat adjuster frame assy 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
Seat adjuster frame assy malfunction
Occupant classification ECU malfunction
Occupant classification sensor rear RH sensed large loadOccupant classification ECU
Seat adjuster frame assy
(Occupant classification sensor rear RH)
HINT:
When DTC B1150/23 is detected as a result of troubleshooting for the supplemental restraint system,
perform troubleshooting for DTC B1788 of the classification system.
Use the hand-held tester to check the DTC of the occupant classification ECU, otherwise the DTC
cannot be read.
WIRING DIAGRAM
see page 05-1474.
INSPECTION PROCEDURE
1 PERFORM ZERO POINT CALIBRATION
(a) Using the hand-held tester, perform ºZero point calibrationº (see page 05-1203).
OK:
The ºCOMPLETEDº is displayed.
NG Go to step 4
OK
2 PERFORM SENSITIVITY CHECK
(a) Using the hand-held tester, perform ºSensitivity checkº (see page 05-1203).
Standard value: 27 to 33 kg (59.52 to 72.75 lb)
NG Go to step 4
OK
05IWY-01
Page 1064 of 2572

- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
05-1491
1681 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
3 CHECK DTC
(a) Turn the ignition switch to the ON position.
(b) Clear the DTCs stored in airbag sensor assy center memory (see page 05-1215).
(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 (see page 05-1215).
OK:
DTC B1788 is not output.
HINT:
Codes other than code B1788 may be output at this time, but they are not related to this check.
NG Go to step 4
OK
END
4 REPLACE SEAT ADJUSTER FRAME ASSY
(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 seat adjuster frame assy (see page 72-1 1, 72-19).
HINT:
Perform the inspection using parts from a normal vehicle when possible.
5 PERFORM ZERO POINT CALIBRATION
(a) Using the hand-held tester, perform ºZero point calibrationº (see page 05-1203).
OK:
The ºCOMPLETEDº is displayed.
NG Go to step 8
OK
6 PERFORM SENSITIVITY CHECK
(a) Using the hand-held tester, perform ºSensitivity checkº (see page 05-1203).
Standard value: 27 to 33 kg (59.52 to 72.75 lb)
NG Go to step 8
OK