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I00497
Cruise Control ECU
B−R BATT
C17
W
W Instrument Panel Fuse Block
Fusible Link
F8 F11
F11
EA3
FL MAIN
Battery 3
ECU−B 15
2
1
N18670
Junction Block No.1
ECU−IG
Fuse
DI−328
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
1996 LAND CRUISER (RM451U)
Back −up Power Source Circuit
CIRCUIT DESCRIPTION
The ECU back− up power source provides power even when the ignition is off and is used for DTC memory,
etc..
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check ECU −IG fuse.
PREPARATION:
Remove the ECU −IG fuse from relay block No.2.
CHECK:
Check continuity of ECU −IG fuse.
OK:
Continuity
NG Check for short in all the harness and compo- nents connected to the ECU −IG fuse.
OK
DI5ON−02
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Page 764 of 1399
AB0119I00013 I00028
ONCMS
(−)
(+)
DI−330
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
1996 LAND CRUISER (RM451U)
Main Switch Circuit (Cruise Control Switch)
CIRCUIT DESCRIPTION
When the cruise control main switch is turned off, the cruise control does not operate.
WIRING DIAGRAM
See page DI−311 .
INSPECTION PROCEDURE
1 Check voltage between terminal CMS of cruise control ECU connector and body
ground.
PREPARATION:
(a) Remove the ECU with connector still connected.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminal CMS of cruise control ECU
connector when main switch is held on and off.
OK:
Main switchVoltage
OFF10 − 14 V
ONBelow 2 V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI−295 ).
NG
DI5OO−02
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Page 766 of 1399
I00498
Cruise Control ECU
C17
Battery Fusible
Link
F6 B−L W
B
B G−Y
F11 F11
GAUGE
Y
2
Y9
CRUISE MAIN Indicator (Combination Meter)C10
C10
2 2 2
2
22
43
EA2
6
Ignition Switch
I12 I12
4
Instrument Panel Fuse Block
1
AM1
AM1 J1
JUNCTION
CONNECTOR
PI
7
DI−332
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
1996 LAND CRUISER (RM451U)
CRUISE MAIN Indicator Light Circuit
CIRCUIT DESCRIPTION
When the cruise control main switch is turned ON, CRUISE MAIN indicator ligh\
t lights up.
WIRING DIAGRAM
DI5OP−02
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Page 767 of 1399
AB0119I00020 I00029
ON
PI
(−)
(+)
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
DI−333
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
1 Check voltage between terminals PI and GND of cruise control ECU connector.
PREPARATION:
Turn ignition switch ON.
CHECK:
Measure voltage between terminals PI and GND of ECU con-
nector when main switch on and off.
OK:
Switch positionVoltage
OFF10 − 16 V
ONBelow 1.2 V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI−295 ).
NG
2 Check combination meter (See page BE−34 ).
NG Replace combination meter.
OK
Check and replace cruise control ECU (See
page IN−28 ).
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Page 768 of 1399
I00499
Cruise Control ECU
DLC1
TC D111
B−Y IH111
B−YC17 TC8
N06219
DLC1
TC
E1
DI−334
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
1996 LAND CRUISER (RM451U)
Diagnosis Circuit
CIRCUIT DESCRIPTION
This circuit sends a signal to the ECU that DTC output is required.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check voltage between terminals Tc and E1 of DLC1.
PREPARATION:
Turn ignition switch ON.
CHECK:
Measure voltage between terminals Tc and E1 of DLC1.
OK:
Voltage: 10 − 14 V
OK Proceed to next circuit inspection shown on problem symptoms table (See page DI−295 ).
NG
DI5OQ−02
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Page 786 of 1399

EM1E0−04
−
ENGINE MECHANICAL CO/HC
EM−1
504
Author: Date:
1996 LAND CRUISER (RM451U)
CO/HC
INSPECTION
HINT:
This check is used only to det ermine whether or not the idle CO/
HC complies with regulations.
1. INITIAL CONDITIONS
(a) Engine at normal operating temperature
(b) Air cleaner installed
(c) All pipes and hoses of air induction system connected
(d) All accessories switched OFF
(e) All vacuum lines properly connected
HINT:
All vacuum hoses for EGR systems, etc. should be properly
connected.
(f) SFI system wiring connectors fully plugged
(g) Ignition timing set correctly
(h) Transmission in neutral position
(i) Tachometer and CO/HC meter calibrated by hand
2. START ENGINE
3. RACE ENGINE AT 2,500 RPM FOR APPROX. 180 SE-
CONDS
4. 4.INSERT CO/HC METER TESTING PROBE AT LEAST
40 cm (1.3 ft) INTO TAILPIPE DURING IDLING
5. IMMEDIATELY CHECK CO/HC CONCENTRATION AT IDLE AND/OR 2,500 RPM
HINT:
When doing the 2 mode (2,500 rpm and idle) test, follow the
measurement order prescribed by the applicable local regula-
tions.
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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
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Page 792 of 1399

EM0494
−
ENGINE MECHANICAL VALVE CLEARANCE
EM−7
510
Author: Date:
1996 LAND CRUISER (RM451U)
9. Rear valves of No. 6 cylinder
ADJUST VALVE CLEARANCE
(a) Remove the distributor (See page IG−10).
(b) Remove the camshafts (See page EM−28).
(c) Remove the adjusting shim with a small screwdriver.
(d) Determine the replacement adjusting shim size by follow- ing the Formula or Charts:
Using a micrometer, measure the thickness of the
removed shim.
Calculate the thickness of a new shim so that the
valve clearance comes within specified value.
T ....... Thickness of removed shim
A ....... Measured valve clearance
N ....... Thickness of new shim
Intake: N = T + (A − 0.20 mm (0.008 in.))
Exhaust: N = T + (A − 0.30 mm (0.012 in.))
Select a new shim with a thickness as close as pos-
sible to the calculated value.
HINT:
Shims are available in 17 sized in increments of 0.05 mm
(0.0020 in.), from 2.50 mm (0.0984 in.) to 3.30 mm (0.1299 in.).
(e) Place a new adjusting shim on the valve lifters.
(f) Install the camshafts (See page EM−54 ).
(g) Recheck the valve clearance.
(h) Install the distributor (See page IG−11 ).
10. REINSTALL CYLINDER HEAD COVER
(a) Install the gasket to the cylinder head cover.
(b) Install the cylinder head cover with the 13 bolts.
11. RECONNECT HIGH −TENSION CORDS TO SPARK
PLUGS (See page IG−1 )
12. RECONNECT HEA TER VALVE AND ENGINE WIRE TO
COWL PANEL
(a) Connect the heater valve with the 2 bolts.
(b) Connect the ground strap and engine wire with the 2 bolts.
13. REINSTALL THROTTLE BODY (See page SF−48 )
14. REFILL RADIATOR WITH ENGINE COOLANT
15. CHECK AND ADJUST IGNITION TIMING (See page EM−10 )
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