Page 505 of 1399
DI−68
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
2 Check for open and short in harness and connector between ECM and crank-
shaft position sensor for NE2 signal (See page IN−28).
NG Repair or replace harness or connector.
OK
3 Inspect sensor installation and teeth of signal plate.
NG Tighten the sensor. Replace signal plate.
OK
Check and replace ECM (See page IN−28 ).
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Page 524 of 1399

P22487
No.1 Vehicle
Speed SensorCombination
Meter ECM
4−pulse
4−pulse
P22473
Combination Meter
3
C13 L−WL
−W8
E7 SPD ECM
5V
E1
From Cruise Control ECU
−
DIAGNOSTICS ENGINE
DI−87
1996 LAND CRUISER (RM451U)
DTC P0500 Vehicle Speed Sensor Malfunction
CIRCUIT DESCRIPTION
The vehicle speed sensor outputs a 4 − pulse signal for every revolution of the rotor shaft, which is rotated
by the transmission output shaft via the driven gear. After this signal is converted into a more precise rectan-
gular wavefrom by the waveform shaping circuit inside the combination meter, it is then transmitted to the
ECM. The ECM determines the vehicle speed based on the frequency of thes\
e pulse signals.
DTC No.DTC Detecting ConditionTrouble Area
P0500
No vehicle speed sensor signal to ECM under conditions (a)
and (b):
(2 trip detection logic)
(a) Park/neutral position switch is OFF.
(b) Vehicle is being driven. Open or short in No.1 vehicle speed sensor circuit
No.1 vehicle speed sensor
Combination meter
ECM
WIRING DIAGRAM
DI5PN−02
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Page 526 of 1399

P22234
From
Air
CleanerSignals ECM IAC ValveValve ShaftRotor
To Cylinders
Throttle Valve
Intake Air
Chamber
Coils
Valve
−
DIAGNOSTICS ENGINE
DI−89
1996 LAND CRUISER (RM451U)
DTC P0505 Idle Control System Malfunction
CIRCUIT DESCRIPTION
The step motor type IAC valve is located in front of the intake
air chamber. Intake air bypassing the throttle valve is directed
to the IAC valve through a passage. A step motor is built into
the IAC valve. It consists of four coils, a magnetic rotor, valve
shaft and valve. When current flows to the coils due to signals
from the ECM, the rotor turns and moves the valve shaft forward
or backward, changing the clearance between the valve and
the valve seat. In this way the intake air volume bypassing the
throttle valve is regulated, controlling the engine speed. There
are 125 possible positions to which the valve can be opened.
DTC No.DTC Detecting ConditionTrouble Area
P0505Idle speed continues to vary greatly from the target speed
(2 trip detection logic)
IAC valve is stuck or closed
Open or short in IAC valve circuit
Open or short in A /C signal circuit
Air intake (hose loose)
DI5PO−02
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Page 530 of 1399

−
DIAGNOSTICS ENGINE
DI−93
1996 LAND CRUISER (RM451U)
DTC P0510 Closed Throttle Position Switch Malfunction
CIRCUIT DESCRIPTION
Refer to DTC P0120 (Throttle/Pedal Position Sensor/Switch ”A” Circuit \
Malfunction) on page DI−35.
DTC No.DTC Detecting ConditionTrouble Area
P0510
The closed throttle position switch does not turn ON or OFF
even once when the vehicle is driven
(2 trip detection logic)Open or short in closed throttle position switch circuit
Closed throttle position switch
ECM
HINT:
After confirming DTC P0510 use the TOYOTA hand−held tester to confirm the closed throttle position switch
signal from ”CURRENT DATA”.
Throttle ValveClosed Throttle Position Switch SignalMalfunction
Fully closedOFFOpen circuit
Fully openONShort circuit
WIRING DIAGRAM
Refer to DTC P0120 (Throttle/Pedal Position Sensor/Switch ”A” Circuit Malfunction) on page DI−35 for WIR-
ING DIAGRAM.
INSPECTION PROCEDURE
HINT:
If DTCs P0110 (Intake Air Temp. Circuit Malfunction), P0115 (Engine Coolant Temp. Circuit Malfunction),
P0120 (Throttle/Pedal Position Sensor/Switch ”A” Circuit Malfunction)\
are output simultaneously, E2 (Sen-
sor Ground) may be open.
TOYOTA hand −held tester
1 Connect the TOYOTA hand −held tester and read CTP switch signal.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect OBD II scan tool or TOYOTA hand−held tester to the DLC3.
(c) Turn ignition switch ON and OBD II scan tool or TOYOTA hand−held tester main switch ON.
CHECK:
Read CTP switch signal on TOYOTA hand −held tester.
RESULT:
Throttle ValveClosed Throttle Position Switch SignalMalfunction
Fully closedOFFOpen circuit: Go to step 2
Fully openONShort circuit: Go to step 4
DI5PP−02
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BE6653
FI7058A00486
Throttle Position
SensorON
4
3
21
1
11
9
10
E5
E5
E5 E5
VTA
ECM
VCC
IDL
E2 E112V
5V
FI7064
A00487
Throttle Position Sensor
4
3
2
11
11
9
10
E5
E5
E5 E5
VTA
ECM
VCC
IDL
E2 E112V
5V
IDL E2
ON
DI−94
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect throttle position sensor connector.
(b) Connect sensor wire harness terminals between terminals 1 and 2.
(c) Turn ignition switch ON.
CHECK:
Read CTP switch signal on TOYOTA hand −held tester.
OK:
CTP switch signal: ON
OK Confirm good connection at sensor. If OK, replace throttle position sensor.
NG
3 Check for open in harness or ECM.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel (See page SF−65 ).
(b) Connect between terminals IDL and E2 of ECM.
HINT:
Throttle position sensor connector is disconnected.
Before checking, do a visual check and contact pressure check
for connector (See page IN−28).
(c) Turn ignition switch ON.
CHECK:
Read CTP switch signal on TOYOTA hand −held tester.
OK:
CTP switch signal: ON
OK Open in harness between ECM and throttle position sensor, repair or replace harness.
NG
Confirm connection at ECM.
If OK, replace ECM (See page IN−28).
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BE6653A00499A00488
Throttle Position Sensor
4
3
2
11
11
9
10
E5
E5
E5 E5
VTA
ECM
VCC IDL1
E2 E112V
5V
ON
BE6653
A00496 A00498
A00489
4
3
2
11
11
9
10
E5
E5
E5 E5
VTA1
ECM
VCC IDL1
E2 12V
5V
ON
Throttle Position
Sensor
E5 Connector
−
DIAGNOSTICS ENGINE
DI−95
1996 LAND CRUISER (RM451U)
4 Check for short in harness or ECM.
PREPARATION:
(a) Disconnect throttle position sensor connector.
(b) Turn ignition switch ON.
CHECK:
Read CTP switch signal on TOYOTA hand −held tester.
OK:
CTP switch signal: OFF
OK Confirm good connection at sensor. If OK, replace throttle position sensor.
NG
5 Check for short in harness or ECM.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel (See page SF−65 ).
(b) Disconnect E5 connector of ECM.
HINT:
Throttle position sensor connector is disconnected.
(c) Turn ignition switch ON.
CHECK:
Read CTP switch signal on TOYOTA hand −held tester.
OK:
CTP switch signal: OFF
OK Short in harness between ECM and throttle position sensor, repair or replace harness.
NG
Confirm connection at ECM.
If OK, replace ECM (See page IN−28).
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Page 533 of 1399
A00492
43
2
11
11
9
10
E5
E5
E5 E5
VTA
ECM
VCC
IDL
E2E1 12V
5V
ON
Throttle Position Sensor
DI−96
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
OBD II scan tool (excluding TOYOTA hand −held tester)
1 Check for open and short in harness or ECM.
PREPARATION:
(a) Disconnect throttle position sensor connector.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals 1 and 2 of throttle position
sensor connector.
OK:
Voltage: 9 − 14 V
OK Confirm good connection at sensor. If OK, replace throttle position sensor.
NG
2 Check for open and short in harness and connector between throttle posit\
ion sensor and ECM (See page IN−28).
NG Open or short in harness between ECM and
throttle position sensor.
OK
Confirm connection at ECM.
If OK, replace ECM (See page IN−28).
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Page 537 of 1399

A00184
STARTIGT
(+)(−)
BE6653
P24674
A00186
ON and START
3
BE6653
P24675
DI−100
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
6 Disconnect igniter connector and check voltage between terminals IGT of ECM
connector and body ground.
PREPARATION:
(a) Disconnect igniter connector.
(b) Remove instrument panel speaker No.1 panel (See page
SF−65 ).
CHECK:
Measure voltage between terminal IGT of ECM connector and
body ground when engine is cranked.
OK:
Voltage: More than 0.1 V and less than 4.5 V
OK Check and replace ECM (See page IN−28 ).
NG
7 Check voltage between terminal 3 of igniter connector and body ground.
PREPARATION:
Disconnect igniter connector.
CHECK:
Measure voltage between terminal 3 of igniter connector and
body ground, when ignition switch is turned to ”ON” and
”START” position.
OK:
Voltage: 9 − 14 V
NG Check and repair igniter power source circuit.
OK
8 Check for open and short in harness and connector between ignition switc\
h and ignition coil, ignition coil and igniter (See page IN−28).
NG Repair or replace harness or connector.
OK
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