Page 1617 of 3115
H21794
S17 Seat Position Sensor
Airbag Sensor Assembly
LSP-
LSP+ C253
BM2
L-RR
C25
C25 C25 R
L-R
BM22
1(*1) (*2)
(*1) (*2)8
4
3
*1: w/ Side Airbag
*2: w/o Side Airbag 1
2 DI-836
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1029 Author: Date:
2004 LAND CRUISER (RM1071U)
DTC B1153/25 Seat Position Sensor Assembly Mal-
function
CIRCUIT DESCRIPTION
The seat position sensor circuit consists of the airbag sensor assembly and the seat position sensor assem-
bly.
For details of the function of each components, see OPERATION on page RS-3.
B1153/25 is recorded when a malfunction is detected in the seat position sensor circuit.
DTC No.DTC Detecting ConditionTrouble Area
B1153/25Seat position sensor assembly malfunction
Seat position sensor assembly
Airbag sensor assembly
Floor No. 1 wire
Front seat wire LH
HINT:
DTC B1153/25 is indicated only for the vehicle equipped with the side airbag and without the side airbag
(dual stage airbag).
WIRING DIAGRAM
DIB3X-01
Page 1618 of 3115
AB0119H10600H16831H19293
ON
DLC3
CG TCDTC B1153/25
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI-837
1030 Author: Date:
2004 LAND CRUISER (RM1071U)
INSPECTION PROCEDURE
1 Is DTC B1153/25 output ?
CHECK:
(a) Turn the ignition switch to ON, and wait at least for 10 se-
conds.
(b) Clear the DTC stored in memory (See page DI-692).
(c) Turn the ignition switch to LOCK, and wait at least for 10
seconds.
(d) Turn the ignition switch to ON, and wait at least for 10 se-
conds.
(e) Check the DTC (See page DI-692).
OK:
DTC B1153/25 is output.
HINT:
Codes other than code B1153/25 may be output at this time, but
they are not relevant to this check.
NO The malfunctioning part can now be considered
normal. To make sure of this, use the simulation
method to check.
YES
2 Is connector of the seat position sensor assembly properly connected ?
NO Connect connector.
YES
3 Prepare for inspection (See step 1 on DI-923).
Page 1619 of 3115

H19236H21576H21582H21738
Airbag
Sensor
Assembly
LSP-
Seat
Position
Sensor
Assembly
Airbag Sensor
Assemblyw/o Side Airbag:
(-) LSP+
(+)
(+)
(-)
Airbag Sensor
Assemblyw/ Side Airbag:
LSP- LSP+
H21577H21583H21739
Airbag
Sensor
Assembly
Seat
Position
Sensor
Assembly
(+)
(-)
Airbag Sensor
Assemblyw/o Side Airbag:
LSP-LSP+LSP+
LSP-
(+)
(-)
Airbag Sensor
Assemblyw/ Side Airbag:
DI-838
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1031 Author: Date:
2004 LAND CRUISER (RM1071U)
4 Check wire harness.
PREPARATION:
Using a service wire, connect LSP+ and LSP- of the connector
on the seat position sensor assembly side between the airbag
sensor assembly and the seat position sensor assembly.
CHECK:
Measure the resistance between LSP+ and LSP- of the con-
nector on the airbag sensor assembly side between the seat
position sensor assembly and the airbag sensor assembly.
OK:
Resistance: Below 1 W
NG Go to step 9.
OK
5 Check wire harness (to ground).
PREPARATION:
Release the service wire from the connector on the seat posi-
tion sensor assembly side.
CHECK:
Measure the resistance between the body ground and each of
LSP+ and LSP- of the connector on the airbag sensor assem-
bly side between the seat position sensor assembly and the air-
bag sensor assembly.
OK:
Resistance: 10 kW or Higher
NG Go to step 10.
OK
Page 1620 of 3115
H21584H21578AB0119H21740
Airbag
Sensor
Assembly
Seat
Position
Sensor
Assembly
(+)
(-)
Airbag Sensor
Assemblyw/o Side Airbag:
LSP-LSP+
LSP+ LSP-
(+)
(-)
Airbag Sensor
Assemblyw/ Side Airbag:
ON
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI-839
1032 Author: Date:
2004 LAND CRUISER (RM1071U)
6 Check wire harness (to B+).
PREPARATION:
Connect the negative (-) terminal cable to the battery, and wait
at least for 2 seconds.
CHECK:
(a) Turn the ignition switch to ON.
(b) Measure the voltage between the body ground and each
of LSP+ and LSP- of the connector on the airbag sensor
assembly side between the seat position sensor assem-
bly and the airbag sensor assembly.
OK:
Voltage: Below 1 V
NG Go to step 11.
OK
Page 1621 of 3115

H10600AB0119H21741
Airbag
Sensor
Assembly
ON
DLC3DTC B1153/25
CG
TC
" u
" u
Seat
Position
Sensor
Assembly
DI-840
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1033 Author: Date:
2004 LAND CRUISER (RM1071U)
7 Check seat position sensor assembly.
PREPARATION:
(a) Turn the ignition switch to LOCK.
(b) Disconnect the negative (-) terminal cable from the bat-
tery, and wait at least for 90 seconds.
(c) Connect the connectors of the seat position sensor as-
sembly and the airbag sensor assembly.
(d) Connect the negative (-) terminal cable to the battery,
and wait at least for 2 seconds.
CHECK:
(a) Turn the ignition switch to ON, and wait at least for 10 se-
conds.
(b) Clear the DTC stored in memory (See page DI-692).
(c) Turn the ignition switch to LOCK, and wait at least for 10
seconds.
(d) Turn the ignition switch to ON, and wait at least for 10 se-
conds.
(e) Check the DTC (See page DI-692).
OK:
DTC B1153/25 is not output.
HINT:
Codes other that code B1153/25 may be output at this time, but
they are not relevant to this check.
NG Replace seat position sensor assembly,
then go to next step.
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.
Page 1622 of 3115

H10600AB0119H21741
Airbag
Sensor
Assembly
ON
DLC3DTC B1153/25
CG
TC
Seat
Position
Sensor
Assembly
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI-841
1034 Author: Date:
2004 LAND CRUISER (RM1071U)
8 Is DTC B1153/25 output again ?
PREPARATION:
(a) Disconnect the negative (-) terminal cable from the bat-
tery, and wait at least for 90 seconds.
(b) Connect the negative (-) terminal cable to the battery,
and wait at least for 2 seconds.
CHECK:
(a) Turn the ignition switch to ON, and wait at least for 10 se-
conds.
(b) Clear the DTC stored in memory (See page DI-692).
(c) Turn the ignition switch to LOCK, and wait at least for 10
seconds.
(d) Turn the ignition switch to ON, and wait at least for 10 se-
conds.
(e) Check the DTC (See page DI-692).
OK:
DTC B1153/25 is not output.
HINT:
Codes other that code B1153/25 may be output at this time, but
they are not relevant to this check.
NG Replace airbag sensor assembly.
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.
Page 1623 of 3115

H21271H19236H21664H21742
Airbag
Sensor
Assembly
Seat
Position
Sensor
Assembly
LSP+
LSP-(+)
(-) Front Seat
Wire LHFloor No. 1 Wire
H21271H21665H21743
Airbag
Sensor
Assembly
Seat
Position
Sensor
Assembly
LSP+LSP-
(+)
(-) Front Seat
Wire LHFloor No. 1 Wire
DI-842
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
1035 Author: Date:
2004 LAND CRUISER (RM1071U)
9 Check front seat wire LH.
PREPARATION:
(a) Disconnect the front seat wire LH connector from the floor
No. 1 wire.
(b) Using a service wire, connect LSP+ and LSP- of the front
seat wire LH connector on the seat position sensor as-
sembly side.
CHECK:
Measure the resistance between LSP+ and LSP- of the front
seat wire LH connector on the floor No. 1 wire side.
OK:
Resistance: Below 1 W
NG Repair or replace front seat wire LH.
OK
Repair or replace floor No. 1 wire.
10 Check front seat wire LH (to ground).
PREPARATION:
(a) Disconnect the front seat wire LH connector from the floor
No. 1 wire.
(b) Release the service wire from the front seat wire LH con-
nector on the seat position sensor assembly side.
CHECK:
Measure the resistance between the body ground and each of
LSP+ and LSP- of the front seat wire LH connector on the floor
No. 1 wire side.
OK:
Resistance: 10 kW or Higher
NG Repair and replace floor No. 1 wire.
OK
Repair and replace floor No. 1 wire.
Page 1624 of 3115
H21271H21666AB0119H21744
Airbag
Sensor
Assembly
Seat
Position
Sensor
Assembly
LSP+LSP-
(+)
(-) Front Seat
Wire LHFloor No. 1 Wire
ON
- DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI-843
1036 Author: Date:
2004 LAND CRUISER (RM1071U)
11 Check front seat wire LH (to B+).
PREPARATION:
Disconnect the front seat wire LH connector from the floor No.
1 wire.
CHECK:
Measure the voltage between the body ground and each of
LSP+ and LSP- of the front seat wire LH connector on the floor
No. 1 wire side.
OK:
Voltage: Below 1 V
NG Repair or replace front seat wire LH.
OK
Repair or replace floor No. 1 wire.