1996 TOYOTA LAND CRUISER Throttle position sensor

A00156
ON
Engine Coolant
Temp. Sensor ECM
5V
4
9
2
1
E2
E1
THW
E5
E5
BE6653
FI7055
−
DIAGNOSTICS ENGINE
DI−31
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
HINT:
If DTC is 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.
1 Connect the OBD II scan tool or TOYOTA hand −held tester, and read value of
engine coolant temperature.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the OBD II scan tool or TOYOTA hand−held tester to the DLC3.
(c) Turn ignition switch ON and push the OBD II scan tool or TOYOTA hand−held tester main switch ON.
CHECK:
Read temperature value on the OBD II scan tool or TOYOTA hand −held tester.
OK:
Same as actual engine coolant temperature.
HINT:
If there is open circuit, OBD II scan tool or TOYOTA hand−held tester indicates − 40°C (− 40 °F).
If there is short circuit, OBD II scan tool or T OYOTA hand−held tester indicates 140 °C (284 °F) or more.
NG −40°C ( −40° F) ... Go to step 2.
140 °C (284° F) or more ... Go to step 4.
OK
Check for intermittent problems
(See page DI−3 ).
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the engine coolant temp. sensor connector.
(b) Connect sensor wire harness terminals together.
(c) Turn ignition switch ON.
CHECK:
Read temp. value on the OBD II scan tool or TOYOTA hand −
held tester.
OK:
Temp. value: 140° C (284°F) or more
OK Confirm good connection at sensor. If OK, replace engine coolant temp. sensor.
NG
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FI6571
Throttle Position
SensorVCCVTA
IDLE2 ECM
5V
B+
−
DIAGNOSTICS ENGINE
DI−35
1996 LAND CRUISER (RM451U)
DTC P0120 Throttle/Pedal Position Sensor/Switch ”A”
Circuit Malfunction
CIRCUIT DESCRIPTION
The throttle position sensor is mounted in the throttle body and
detects the throttle valve opening angle.
When the throttle valve is fully closed, the IDL contacts in the
throttle position sensor are on, so the voltage at the terminal IDL
of the ECM becomes 0 V. At this time, a voltage of approximate-
ly 0.3 − 0.8 V is applied to terminal VTA of the ECM. When the
throttle valve is opened, the IDL contacts go off and thus the
power source voltage of approximately 12 V in the ECM is ap-
plied to the terminal IDL of the ECM. The voltage applied to the
terminal VTA of the ECM increases in proportion to the opening
angle of the throttle valve and becomes approximately 3.2 − 4.9
V when the throttle valve is fully opened. The ECM judges the
vehicle driving conditions from these signals input from termi-
nals VTA and IDL, and uses them as one of the conditions for
deciding the air− fuel ratio correction, power increase correction
and fuel −cut control etc.
DTC No.DTC Detecting ConditionTrouble Area
P0120
Condition (a) or (b) continues
(a) VTA < 0.1 V, and closed throttle position switch is OFF
(b) VTA > 4.9 VOpen or short in throttle position sensor circuit
 Throttle position sensor
 ECM
HINT:
If there is open circuit in IDL line, DTC P0120 does not indicate.
After confirming DTC P0120 use the OBD II scan tool or TOYOTA hand−held tester to confirm the
throttle valve opening percentage and closed throttle position switch condition\
.
Throttle valve opening position
expressed as percentage
Trouble Area
Throttle valve fully closedThrottle valve fully open
0 %0 %VCC line open
VTA line open or short
Approx. 99 %Approx. 100 %E2 line open
DI5P7−02
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A00483
2
1 3 4R−G
G−B
G−W
BR−B
Throttle Position Sensor
* Closed Throttle
Position Switch
* E5 E5
E5 E5
10 1
11 9 VTA
E2 VCC
IDL 5V
E1 B+
P22422
ECM
FI7052
DI−36
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
WIRING 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.
1 Connect the OBD II scan tool or TOYOTA hand −held tester and read the throttle
valve opening percentage.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the OBD II scan tool or TOYOTA hand−held tester to DLC3.
(c) Turn ignition switch ON and push the OBD II scan tool or TOYOTA hand−held tester main switch ON.
CHECK:
Read the throttle valve opening percentage.
OK:
Throttle valveThrottle valve opening positionexpressed as percentage
Fully openApprox. 75 %
Fully closedApprox. 10 %
OK Check for intermittent problems (See page DI−3 ).
NG
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A00160BE6653
P24657
ON1
−
DIAGNOSTICS ENGINE
DI−37
1996 LAND CRUISER (RM451U)
2 Check voltage between terminal 1 of wire harness side connector and body
ground.
PREPARATION:
(a) Disconnect the throttle position sensor connector.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminal 1 of wire harness side con-
nector and body ground.
OK:
Voltage: 4.5 − 5.5 V
NG Go to step 5.
OK
3 Check throttle position sensor (See page SF−42).
NG Replace throttle position sensor.
OK
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A00161
ON
BE6653
P24658
(+) (−)
VTA
E2
A00162
ON
VCC E2
(+) (−)
BE6653
P24659
DI−38
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
4 Check voltage between terminals VTA and E2 of ECM.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel
(See page SF−65 ).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals VTA and E2 of ECM.
OK:
Throttle valveVoltage
Fully closed0.3 − 0.8 V
Fully open3.2 − 4.9 V
NG Check for open and short in harness and
connector between ECM and throttle
position sensor (VTA line) (See page IN−28).
OK
Check and replace ECM (See page IN−28 ).
5 Check voltage between terminals VCC and E2 of ECM.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel
(See page SF−65 ).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals VCC and E2 of ECM con-
nector.
OK:
Voltage: 4.5 − 5.5 V
NG Check and replace ECM (See page IN−28 ).
OK
Check for open in harness and connector
between ECM and sensor (VCC line)
(See page IN−28 ).
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−
DIAGNOSTICS ENGINE
DI−39
1996 LAND CRUISER (RM451U)
DTC P0121 Throttle/Pedal Position Sensor/Switch ”A”
Circuit Range/Performance Problem
CIRCUIT DESCRIPTION
Refer to DTC P0120 (Throttle/Pedal Position Sensor/Switch "A" Circuit Malfunction) on page DI−35.
DTC No.DTC Detection ConditionTrouble Area
P0121
After the vehicle speed has been exceeded 30 km/h (19 mph)
even once, the output value of the throttle position sensor is
out of the applicable range while the vehicle speed between 30
km/h (19 mph) and 0 km/h (0 mph).
Throttle position sensor
INSPECTION PROCEDURE
1 Are there any other codes (besides DTC P0121) being output?
YES Go to relevant DTC chart.
NO
Replace throttle position sensor.
DI5P8−02
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P21242 FI7210A00027
Atmosphere
Flange
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating (Ceramic)
Exhaust GasCover Ideal Air−
Fuel Mixture
Output Voltage
Richer − Air Fuel Ratio − Leaner
DI−40
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
DTC P0125 Insufficient Coolant Temp. for Closed Loop
Fuel Control
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of th\
e exhaust gas, a three −way cata-
lytic converter is used, but for the most efficient use of the three −way catalytic converter, the air−fuel ratio
must be precisely controlled so that it is always close to the stoichiom\
etric air −fuel ratio.
The oxygen sensor has the characteristic where by its output voltage change\
s suddenly in the vicinity of the
stoichiometric air −fuel ratio. This characteristic is used to detect the oxygen concentrati\
on in the exhaust
gas and provide feedback to the computer for control of the air −fuel ratio.
When the air −fuel ratio becomes LEAN, the oxygen concentration in the exhaust increas\
es and the oxygen
sensor informs the ECM of the LEAN condition (small electromotive force: 0 V)\
.
When the air −fuel ratio is RICHER than the stoichiometric air −fuel ratio the oxygen concentration in the ex-
haust gas in reduced and the oxygen sensor informs the ECM of the RICH condit\
ion (large electromotive
force: 1 V). The ECM judges by the electromotive force from the oxygen \
sensor whether the air −fuel ratio
is RICH or LEAN and controls the injection time accordingly. However, if malfunction of the oxygen sensor
causes output of abnormal electromotive force, the ECM is unable to perform acc\
urate air −fuel ratio control.
The heated oxygen sensors include a heater which heats the zirconia element\
. The heater is controlled by
the ECM. When the intake air volume is low (the temp. of the exhaust gas i\
s low) current flows to the heater
to heat the sensor for accurate oxygen concentration detection.
DTC No.DTC Detecting ConditionTrouble Area
P0125
After the engine is warmed up, heated oxygen sensor (bank 1
sensor 2) output does not indicate RICH even once when
conditions (a), (b) and (c) continue for at least 1.5 min.
(a) Engine speed: 1,500 rpm or more
(b) Vehicle speed: 40 − 100 km/h (25 − 62 mph)
(c) Closed throttle position switch: OFF
 Open or short in heated oxygen sensor (bank 1 sensor 1)
circuit
 Heated oxygen sensor (bank1 sensor 1)
DI5P9−02
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−
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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