1996 TOYOTA LAND CRUISER sensor

FI4741
(fig.1)Acceptable
Resistance kΩ
− 20 0 20 40 60 80 100
( − 4) 32 68 104 140 176 212
30
20
10
53
2
1
0.5
0.3
0.2
0.1
Temp. °C (F °)
DI−26
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
DTC P0110 Intake Air Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
The intake air temperature sensor is built into the air flow meter
and senses the intake air temperature.
A thermistor built in the sensor changes the resistance value
according to the intake air temperature. The lower the intake air
temperature, the greater the thermistor resistance value, and
the higher the intake air temperature, the lower the thermistor
resistance value (See fig.1).
The intake air temperature sensor is connected to the ECM
(See next page). The 5 V power source voltage in the ECM is
applied to the intake air temperature sensor from the terminal
THA via a resistor R.
That is, the resistor R and the intake air temperature sensor are
connected in series. When the resistance value of the intake air
temperature sensor changes in accordance with changes in the
intake air temperature, the potential at terminal THA also
changes. Based on this signal, the ECM increases the fuel in-
jection volume to improve driveability during cold engine opera-
tion.
If the ECM detects the DTC ”P0110”, it operates the fail safe
function in which the intake air temperature is assumed to be
20 °C (68 °F).
Intake Air Temp.
° C (° F)Resistance
(kΩ)Voltage
(V)
−20 (− 4)16.24.3
0 (32)5.93.4
20 (68)2.52.4
40 (104)1.11.4
60 (140)0.60.9
80 (176)0.30.5
100 (212)0.10.2
DTC No.DTC Detecting ConditionTrouble Area
P0110Open or short in intake air temp. sensor circuit
Open or short in intake air temp. sensor circuit
 Intake air temp. sensor
 ECM
HINT:
After confirming DTC P110 use the OBD II scan tool or TOYOTA hand −held tester to confirm the intake air
temp. from ”CURRENT DATA”.
Temp. DisplayedMalfunction
− 40° C (− 40°F)Open circuit
140°C (284°F) or moreShort circuit
DI5P1−02
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A00484
Intake Air Temp. Sensor
(Inside the mass air flow meter)
3
4 L−Y
BR−B 5V
ECM
E5
E5
THA
E1
E2
P22420
3
9 R
−
DIAGNOSTICS ENGINE
DI−27
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 value of
intake air temperature.
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 OBD II scan tool or TOYOTA hand−held tester main switch ON.
CHECK:
Read temp. value on the OBD II scan tool or TOYOTA hand −held tester.
OK:
Same as actual intake air temp.
HINT:
If there is open circuit, push OBD II scan tool or TOYOTA hand− held tester indicates − 40° C (− 40°F).
If there is short circuit, OBD II scan tool or TOYOTA handheld 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 ).
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A00154
ON
Intake Air
Temp. Sensor ECM
5V
E2 E1
3
4 3
9
E5
E5
BE6653
FI7055 A00154 THA
A00150
ON
Intake Air
Temp. Sensor ECM
5V
3
9 E2
E1
THA E2
THA
E5
E5
BE6653
FI7057
P24655
DI−28
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the mass air flow meter 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 mass air flow meter.
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 THA and E2 of ECM connec-
tor.
HINT:
Mass air flow meter connector is disconnected.
Before checking, do a visual and contact pressure check for the
ECM connector (See page IN−28).
(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 Open in harness between terminals E2 or THA, repair or replace harness.
NG
Confirm good connection at ECM.
If OK, replace ECM (See page IN−28).
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A00151
ON
Intake Air
Temp. Sensor 3
4 ECM
3
9 5V
E2 E1
THA
E5
E5
BE6653
FI7054
A00155
ON
Intake Air
Temp. Sensor ECM
E5 connector 5V
E2 E1
THA
BE6653
FI7056
P19798
−
DIAGNOSTICS ENGINE
DI−29
1996 LAND CRUISER (RM451U)
4 Check for short in harness and ECM.
PREPARATION:
(a) Disconnect the mass air flow meter connector.
(b) Turn ignition switch ON.
CHECK:
Read temp. value on the OBD II scan tool or TOYOTA hand −
held tester.
OK:
Temp. value: − 40° C (− 40°F)
OK Replace mass air flow meter.
NG
5 Check for short in harness or ECM.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel (See page SF−65 ).
(b) Disconnect the E5 connector of ECM.
HINT:
Mass air flow meter connector is disconnected.
(c) Turn ignition switch ON.
CHECK:
Read temp. value on the OBD II scan tool or TOYOTA hand −
held tester.
OK:
Temp. value: − 40°C (− 40 °F)
OK Repair or replace harness or connector (See page IN−28 ).
NG
Check and replace ECM (See page IN−28 ).
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Version 1.11 - 03/16/2010

A00485
Engine Coolant Temp. Sensor2
1 R−W
BR−B 5V
ECM
E5
E5
THW
E1
E2
4
9
P22421
DI−30
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
DTC P0115 Engine Coolant Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
A thermistor built into the engine coolant temperature sensor changes the\
resistance value according to the
engine coolant temperature.
The structure of the sensor and connection to the ECM is the same as in the\
intake air temp. circuit malfunc-
tion shown on page DI−26.
If the ECM detects the DTC P0115, it operates the fail safe function in which the engine coolant temp.\
is
assumed to be 80 °C (176
°F).
DTC No.Detection ItemTrouble Area
P0115Open or short in engine coolant temp. sensor circuit
 Open or short in engine coolant temp. sensor circuit
 Engine coolant temp. sensor
 ECM
HINT:
After confirming DTC P0115 use the OBD II scan tool or TOYOTA hand −held tester to confirm the engine
coolant temp. from CURRENT DATA.
Temp. DisplayedMalfunction
− 40° C (− 40°F)Open circuit
140°C (284°F) or moreShort circuit
WIRING DIAGRAM
DI5P5−02
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Version 1.11 - 03/16/2010

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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Version 1.11 - 03/16/2010

A00157
ONECM
Engine Coolant
Temp. Sensor
5V
E2 E1
2
1
THW E2
THW
E5
E54
9
BE6653
FI7057
P24656
A00158
ON
Engine Coolant
Temp. Sensor ECM
5V
4
9 E2
E1
THW
BE6653
FI7054 E5
E5
DI−32
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
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 THW and E2 of ECM connec-
tor.
HINT:
Engine coolant temp. sensor connector is disconnected. Be-
fore checking, do a visual and contact pressure check for the
ECM connector (See page IN−28).
(c) Turn ignition switch ON.
CHECK:
Read temperature value on the OBD II scan tool or TOYOTA
hand −held tester.
OK:
Temperature value: 140° C (284°F) or more
OK Open in harness between terminals E2 or THW, repair or replace harness.
NG
Confirm good connection at ECM.
If OK, replace ECM (See page IN−28).
4 Check for short in harness or ECM.
PREPARATION:
(a) Disconnect the engine coolant temp. sensor connector.
(b) Turn ignition switch ON.
CHECK:
Read temperature value on the OBD II scan tool or TOYOTA
hand−held tester.
OK:
Temperature value: − 40° C (− 40°F)
OK Replace engine coolant temp. sensor.
NG
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Version 1.11 - 03/16/2010

A00159
ON
Engine Coolant
Temp. Sensor ECM
5V
E2 E1
E5 connector
THW
BE6653
FI7056
P19798
−
DIAGNOSTICS ENGINE
DI−33
1996 LAND CRUISER (RM451U)
5 Check for short in harness or ECM.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel
(See page SF−65 ).
(b) Disconnect the E5 connector of ECM.
HINT:
Engine coolant temp. sensor connector is disconnected.
(c) Turn ignition switch ON.
CHECK:
Read temperature value on the OBD II scan tool or TOYOTA
hand −held tester.
OK:
Temperature value: − 40° C (− 40°F)
OK Repair or replace harness or connector.
NG
Check and replace ECM (See page IN−28 ).
Brought to you by BirfMark
Brought to you by BirfMark
Version 1.11 - 03/16/2010