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
Brought to you by BirfMark
Brought to you by BirfMark
Version 1.11 - 03/16/2010
Page 733 of 1399
N18670
Instrument Panel Fuse Block
STOP Fuse
I00133
1
2
43
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
DI−299
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
1 Check STOP fuse.
PREPARATION:
(a) Turn ignition switch OFF.
(b) Remove the STOP fuse from instrument panel fuse block.
CHECK:
Check fuse continuity.
OK:
There is continuity.
NG Replace STOP fuse.
OK
2 Check stop light switch.
PREPARATION:
Disconnect the stop light switch connector.
CHECK:
Check continuity between terminals.
Switch positionContinuity
Switch pin free
(Brake pedal depressed)1 − 2
Switch pin pushed in
(Brake pedal released)3 − 4
NG Replace stop light switch.
OK
Brought to you by BirfMark
Brought to you by BirfMark
Version 1.11 - 03/16/2010
Page 748 of 1399

Input SignalIndicator Light
Blinking Pattern
Stop Light
switch ON
Light ON
OFF SW OFF
SW ON
DI−314
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
1996 LAND CRUISER (RM451U)
Stop Light Switch Circuit
CIRCUIT DESCRIPTION
When the brake pedal is depressed, the stop light switch sends a signal to th\
e ECU. When the ECU receives
this signal, it cancels the cruise control.
A fail− safe function is provided so that the cancel functions normally , even if there is a malfunction in the stop
light signal circuit.
The cancel conditions are: Battery positive voltage at terminal STP −
When the brake is on, battery positive voltage normally applies through the S\
TOP fuse and stop light switch
to terminal STP− of the ECU, and the ECU turns the cruise control off.
If the harness connected to terminal STP − has an open circuit, terminal STP − will have battery positive volt-
age and the cruise control will be turned off.
Also, when the brake is on, the magnetic clutch circuit is cut mechanically \
by the stop light switch, turning
the cruise control off (See page DI−298 for operation of the magnetic clutch).
WIRING DIAGRAM
See page DI−298 .
INSPECTION PROCEDURE
1 Check operation of stop light.
CHECK:
Check that stop light comes on when brake pedal is depressed, and turns off when brake pedal is released.
NG Check stop light system (See page BE−24 ).
OK
2 Input signal check.
CHECK:
(a) See input signal check on DI−286.
(b) Check the indicator light when the brake pedal is de-
pressed.
OK:
The indicator light goes off when the brake pedal is
depressed.
OK Proceed to next circuit inspection shown on problem symptoms table (See page DI−295 ).
NG
DI5OI−02
Brought to you by BirfMark
Brought to you by BirfMark
Version 1.11 - 03/16/2010
Page 749 of 1399
AB0119I00015 I00024
ON
STP−
(−) (+)
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
DI−315
1996 LAND CRUISER (RM451U)
3 Check voltage between terminal STP− of cruise control ECU connector and
body ground.
PREPARATION:
(a) Remove the ECU with connectors still connected.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminal STP− of cruise control ECU
connector and body ground, when the brake pedal is de-
pressed and released.
OK:
Depressed10 − 14 V
ReleasedBelow 1 V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI−295 ).
NG
4 Check for open in harness and connectors between terminal STP − of cruise con-
trol ECU and stop light switch (See page IN−28).
NG Repair or replace harness or connector.
OK
Check and replace cruise control ECU (See
page IN−28 ).
Brought to you by BirfMark
Brought to you by BirfMark
Version 1.11 - 03/16/2010
Page 787 of 1399

EM−2
−
ENGINE MECHANICAL CO/HC
505
Author: Date:
1996 LAND CRUISER (RM451U)
6. TROUBLESHOOTING
If the CO/HC concentration does not comply with regulations,
troubleshoot in the order given below.
See the table below for possible causes, and then inspect and
correct the applicable causes if necessary.
COHCProblemsCauses
NormalHighRough idle
3. Faulty ignitions:
Incorrect timing
Fouled, shorted or improperly gapped plugs
Open or crossed high −tension cords
Cracked distributor cap
4. Incorrect valve clearance
5. Leaky EGR valve
6. Leaky intake and exhaust valves
7. Leaky cylinders
LowHighRough idle
(Fluctuating HC reading)
1. Vacuum leaks:
PCV hose
EGR valve
Intake manifold
Air intake chamber
Throttle body
IAC valve
Brake booster line
2. Lean mixture causing misfire
HighHighRough idle
(Black smoke from exhaust)
1. Restricted air filter
2. Faulty SFI systems:
Faulty pressure regulator
Clogged fuel return line
Defective ECT sensor
Faulty ECM
Faulty injector
Faulty throttle position sensor
Faulty MAF meter
Brought to you by BirfMark
Brought to you by BirfMark
Version 1.11 - 03/16/2010
Page 813 of 1399

EM1E3−01
EM−28
−
ENGINE MECHANICAL CYLINDER HEAD
1996 LAND CRUISER (RM451U)
REMOVAL
1. DRAIN ENGINE COOLANT
2. REMOVE BATTERY AND BATTERY TRAY
(a) Disconnect the battery cables.
(b) Remove the nuts, hold −down clamp and battery.
(c) Remove the bolt and disconnect the ground strap.
(d) Remove the 5 bolts and battery tray.
3. REMOVE AIR CLEANER HOSE AND CAP
4. DISCONNECT CRUISE CONTROL ACTUATOR CABLE FROM THROTTLE BODY
5. DISCONNECT ACCELERATOR CABLE FROM
THROTTLE BODY
6. DISCONNECT THROTTLE CABLE FROM THROTTLE BODY
7. DISCONNECT ENGINE GROUND STRAPS
(a) Disconnect the ground strap from the No. 1 engine hang-
er.
(b) Disconnect the ground strap from the air intake chamber.
8. DISCONNECT CONNECTOR ON INTAKE MANIFOLD FROM LH FENDER APRON
9. DISCONNECT BRAKE BOOSTER VACUUM HOSE
10. DISCONNECT EVAP HOSE
11. DISCONNECT FUEL RETURN HOSE
12. DISCONNECT HEATER HOSES
13. DISCONNECT ENGINE WIRE AND HEATER VALVE FROM COWL PANEL
(a) Remove the 2 bolts and disconnect the engine wire and
ground strap.
(b) Remove the 2 bolts and disconnect the heater valve.
14. REMOVE NO. 2 AND NO. 3 CYLINDER HEAD COVERS
Remove the 4 bolts and head covers.
15. REMOVE DISTRIBUTOR (See page IG−10 )
Brought to you by BirfMark
Brought to you by BirfMark
Version 1.11 - 03/16/2010
Page 848 of 1399

−
ENGINE MECHANICAL CYLINDER HEAD
EM−63
1996 LAND CRUISER (RM451U)
24. CONNECT NO. 3 WATER BYPASS HOSE
25. CONNECT RADIATOR INLET HOSE
26. CONNECT PS RESERVOIR TANK
Connect the reservoir tank with the 3 bolts.
Torque: 20 N·m (200 kgf·cm, 14 ft·lbf)
27. INSTALL DISTRIBUTOR (See page IG−11)
28. INSTALL NO. 2 AND NO. 3 CYLINDER HEAD COVERS
Install the head covers with the 4 bolts.
29. CONNECT HEATER VALVE AND ENGINE WIRE TO COWL PANEL
(a) Connect the heater valve with the 2 bolts.
(b) Connect the engine wire and ground strap with the 2 bolts.
30. CONNECT HEATER HOSES
31. CONNECT FUEL RETURN HOSE
32. CONNECT EVAP HOSE
33. CONNECT BRAKE BOOSTER VACUUM HOSE
34. CONNECT CONNECTOR ON INTAKE MANIFOLD TO LH FENDER APRON
35. CONNECT ENGINE GROUND STRAPS
(a) Connect the ground strap to the No. 1 engine hanger.
(b) Connect the ground strap to the air intake chamber.
36. CONNECT THROTTLE CABLE TO THROTTLE BODY
37. CONNECT ACCELERATOR CABLE TO THROTTLE
BODY
38. CONNECT CRUISE CONTROL ACTUATOR CABLE TO
THROTTLE BODY
Brought to you by BirfMark
Brought to you by BirfMark
Version 1.11 - 03/16/2010
Page 855 of 1399

EM−70
−
ENGINE MECHANICAL ENGINE UNIT
1996 LAND CRUISER (RM451U)
13. DISCONNECT ENGINE WIRE AND HEATER VALVE
FROM COWL PANEL
(a) Remove the 2 bolts and disconnect the engine wire and
ground strap.
(b) Remove the 2 bolts and disconnect the heater valve.
14. DISCONNECT BRAKE BOOSTER VACUUM HOSE
15. DISCONNECT EVAP HOSE
16. DISCONNECT FUEL HOSES
(a) Disconnect the fuel return hose.
(b) Remove the union bolt and 2 gaskets, and disconnect the
fuel inlet hose from the fuel filter.
17. DISCONNECT WIRES AND CONNECTORS
(a) Disconnect the 2 heated oxygen sensor connectors.
(b) Disconnect the DLC1 clamp.
(c) Disconnect the 2 oil pressure gauge connectors.
(d) Disconnect the generator wire and connector.
(e) Disconnect the connector on the intake manifold from the
fender apron.
(f) Disconnect the high−tension cord from the ignition coil.
(g) Disconnect the ground strap from the No. 1 engine hang-
er.
(h) Disconnect the ground strap from the air intake chamber.
(i) Disconnect the starter wire.
(j) Disconnect the ground cable from the cylinder block.
18. DISCONNECT A/C COMPRESSOR AND BRACKET
(a) Loosen the idler pulley nut and adjusting bolt, and remove
the drive belt.
(b) Remove the 4 mounting bolts, and disconnect the com-
pressor from the bracket.
HINT:
Put aside the compressor, and suspend it.
(c) Remove the 5 bolts and A/C compressor bracket.
19. REMOVE RADIATOR PIPE
(a) Remove the 2 nuts holding the radiator pipe to the No. 1 oil pan.
(b) Disconnect the No. 2 radiator hose from the water inlet and remove the radiator pipe.
Brought to you by BirfMark
Brought to you by BirfMark
Version 1.11 - 03/16/2010