Page 700 of 1399
R15195
Airbag Sensor
Assembly
1 2 12
B−R
W−R
P
+
P−
P Squib
−
DIAGNOSTICS SUPPLEMENTAL RESTRAINT SYSTEM
DI−267
1996 LAND CRUISER (RM451U)
DTC 54 Open in P Squib Circuit
CIRCUIT DESCRIPTION
The P squib circuit consists of the airbag sensor assembly and front passen\
ger airbag assembly.
It causes the airbag to deploy when the airbag deployment conditions are\
satisfied.
For details of the function of each component, see FUNCTION OF COMPONENT\
S on page RS−2.
DTC 54 is recorded when an open is detected in the P squib circuit.
DTC No.DTC Detection ConditionTrouble Area
54
Open circuit in P+ wire harness or P− wire harness of
squib
Squib malfunction
Airbag sensor assembly malfunctionFront passenger airbag assembly (P squib)
Airbag sensor assembly
Wire harness
WIRING DIAGRAM
DI5QB−03
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Page 704 of 1399

R13678
Airbag Sensor
Assembly
Battery F/B
R/B No.2
2
2
1
1
36 4
6 10
9
S4
GR
B
W
L−R
B−L
B−R ACC
IG2
A
IGN
AM1
AM2
FL BLOCK
W−R
B−L
W−R
Ignition
Switch
B
EA2
EA2
4
11 3
CIG
J3 Junction
Connector
GR 4
33
S5 S5
S4
A
2 2
50A AM1
2
2
Short ConnectorGR
B−W
−
DIAGNOSTICS SUPPLEMENTAL RESTRAINT SYSTEM
DI−271
1996 LAND CRUISER (RM451U)
DTC Normal Source Voltage Drop
CIRCUIT DESCRIPTION
The SRS is equipped with a voltage −increase circuit (DC−DC converter) in the airbag sensor assembly in
case the source voltage drops.
When the battery voltage drops, the voltage −increase circuit (DC−DC converter) functions to increase the
voltage of the SRS to normal voltage.
The diagnosis system malfunction display for this circuit is different to other circuits −when the SRS warning
light remains lit up and the DTC is a normal code, source voltage drop is ind\
icated.
Malfunction in this circuit is not recorded in the airbag sensor assembly, and the source voltage returns to
normal, the SRS warning light automatically goes off.
DTC No.DTC Detection ConditionTrouble Area
NormalSource voltage dorp Battery
Airbag sensor assembly
WIRING DIAGRAM
DI5QC−03
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Page 707 of 1399

R13679
BatteryFL BLOCK 2
MAIN
W
W
ECU−B
1
F/B
S7
B−R
2
3
SRS Warning
Light
8LA
Tc
B−Y8
IH1 Airbag Sensor
Assembly
DLC1
5 W−L
11
GENERATOR
(ALTERNATOR)
W
Cruise Control ECU
W−L
W−L
B−Y
B−Y
IH1 S7 S6
S6
Short Connector
Short Connector W−L
B−L
11
12
3
EA3 11
22
7
DI−274
−
DIAGNOSTICS SUPPLEMENTAL RESTRAINT SYSTEM
1996 LAND CRUISER (RM451U)
SRS Warning Light System Malfunction (Always lit up, when igni-
tion switch is in LOCK position.)
CIRCUIT DESCRIPTION
The SRS warning light is located on the combination meter.
When the SRS is normal, the SRS warning light lights up for approx. 6 seconds after the \
ignition switch is
turned from LOCK position to ACC or ON position, and then turns off automatically.
If there is a malfunction in the SRS, the SRS warning light lights up to\
inform the driver of the abnormality.
When terminals Tc and E1 of the DLC1 are connected, the DTC is displayed by the blinking\
of the SRS warn-
ing light.
WIRING DIAGRAM
DI5QD−03
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Page 709 of 1399

N14677
Fuse
DI−276
−
DIAGNOSTICS SUPPLEMENTAL RESTRAINT SYSTEM
1996 LAND CRUISER (RM451U)
SRS Warning Light System Malfunction (Does not light up, when
ignition switch is turned to ACC or ON.)
CIRCUIT DESCRIPTION
The SRS warning light is located on the combination meter.
When the SRS is normal, the SRS warning light lights up for approx. 6 seconds after the \
ignition switch is
turned from LOCK position to ACC or ON position, and then turns off automatically.
If there is a malfunction in the SRS, the SRS warning light lights up to\
inform the driver of the abnormality.
When terminals Tc and E1 of the DLC1 are connected, the DTC is displayed by the blinking\
of the SRS warn-
ing light.
WIRING DIAGRAM
Refer to page DI−274 for the WIRING DIAGRAM.
INSPECTION PROCEDURE
1 Check ECU−B Fuse.
PREPARATION:
Remove ECU−B fuse.
CHECK:
Check continuity of ECU −B fuse.
OK:
Continuity
HINT:
Fuse may be burnt out even if it appears to be OK during
visual inspection.
If fuse is OK, install it.
NG Go to step 5.
OK
2 Preparation. (See step 1 on page DI−271)
DI5QE−03
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Page 712 of 1399
R13680
Airbag Sensor
AssemblyTc7
B−L
IH1B−Y
11
3
Tc E 1
DLC1 BR−B
EC
S6
S7 11
B−Y
Short Connector 2
2
−
DIAGNOSTICS SUPPLEMENTAL RESTRAINT SYSTEM
DI−279
1996 LAND CRUISER (RM451U)
Tc Terminal Circuit
CIRCUIT DESCRIPTION
By connecting terminals Tc and E1 of the DLC1 the airbag sensor assembly is set in the DTC output mode.
The DTCs are displayed by the blinking of the SRS warning light.
WIRING DIAGRAM
DI5QF−03
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Page 730 of 1399
DI5OB−02
Duty Ratio =A + BA
x 100 (%)
ON
OFF A
B
1 cycle
I00488
Cruise Control ECU
MC
11
C17 MO
L
Cruise Control Actuator
L−RC17
7
6 12
C4
C4
DI−296
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
1996 LAND CRUISER (RM451U)
CIRCUIT INSPECTION
DTC 11 Actuator Motor Circuit
CIRCUIT DESCRIPTION
The actuator motor is operated by signals from the ECU. Acceleration and deceleration signals are trans-
mitted by changes in the Duty Ratio (See note below).
Duty Ratio
The duty ratio is the ratio of the period of continuity in one cycle. For e\
xample, if A is the period of continuity
in one cycle, and B is the period of non −continuity, then.
DTC No.Detection ItemTrouble Area
11Short in actuator motor circuit.
Actuator motor
Harness or connector between cruise control ECU and
actuator motor
Cruise control ECU
WIRING DIAGRAM
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Page 732 of 1399

I00489
Cruise Control ECUL
L−
W−B
1
5
4 3
2 R
1026
C4 Stop Light Switch
4
R−G
Cruise
Control Actuator
C17
C17
C17
C4S13
S13 S13
S13
G−O G−WF11F11
1
2
STOP
Instrument Panel Fuse Block
W
EA3
W
3
1
F8
Battery Fusible Link
FL MAIN
STP−
DI−298
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
1996 LAND CRUISER (RM451U)
DTC 12 Actuator Magnetic Clutch Circuit
CIRCUIT DESCRIPTION
This circuit turns on the magnetic clutch inside the actuator during cruise \
control operation according to the
signal from the ECU. If a malfunction occurs in the actuator or speed sensor, etc. during cruise control opera-
tion, the rotor shaft between the motor and control plate is released.
When the brake pedal is depressed, the stop light switch turns on, supplying electrical power to the stop light.
Power supply to the magnetic clutch is mechanically cut and the magnetic clut\
ch is turned OFF.
When driving downhill, if the vehicle speed exceeds the set speed by 15 km/h\
(9 mph), the ECU turns the
safety magnet clutch OFF. If the vehicle speed later drops to within 10 km/h (6 mph) above the\
set speed,
then cruise control at the set speed is resumed.
DTC No.Detection ItemTrouble Area
12 Short in actuator magnetic clutch circuit.
Open (0.8 sec.) in actuator magnetic clutch circuit.
STOP Fuse
Stop light switch
Actuator magnetic clutch
Harness or connector between cruise control ECU and
actuator magnetic clutch, actuator magnetic clutch and body
ground
Cruise control ECU
WIRING DIAGRAM
DI5OC−02
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Page 735 of 1399
I00490
Cruise Control ECUVR1 VR2
VR3
23
24
25
Y
Y−G Y−L
1
2 3
C4
Cruise Control Actuator
C17
C17 C17
C4
C4
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
DI−301
1996 LAND CRUISER (RM451U)
DTC 13 Actuator Position Sensor Circuit
CIRCUIT DESCRIPTION
The circuit detects the rotation position of the actuator control plate and\
sends a signal to the ECU.
DTC No.Detection ItemTrouble Area
13Position sensor detects abnormal voltage.
Actuator position sensor
Harness or connector between cruise control ECU and
actuator position sensor
Cruise control ECU
WIRING DIAGRAM
DI5OD−02
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Version 1.11 - 03/16/2010