engine TOYOTA T100 1996 Factory Service Manual

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(fig.1)
Acceptable
Resistance kΩ
− 20 0 20 40 60 80 100
(− 4) 32 68 104 140 176 212 30
20
10
5
3
2
1
0.5
0.3
0.2
0.1
Temp.°C (F°)
− DIAGNOSTICSENGINE (3RZ−FE)
DI−27
1996 TOYOTA T100 (RM449U)
DTC P0110 Intake Air Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
The intake air temp. sensor is built into the air cleaner cap and
sensors the intake air temp.
A thermistor built in the sensor changes the resistance value
according to the intake air temp. The lower the intake air temp.,
the greater the thermistor resistance value, and the higher the
intake air temp., the lower the thermistor resistance value (See
fig.1).
The intake air temp. sensor is connected to the ECM (See be-
low). The 5 V power source voltage in the ECM is applied to the
intake air temp. sensor from the terminal THA via a resistor R.
That is, the resistor R and the intake air temp. sensor are con-
nected in series. When the resistance value of the intake air
temp. sensor changes in accordance with changes in the intake
air temp., the potential at terminal THA also changes. Based on
this signal, the ECM increases the fuel injection volume to im-
prove driveability during cold engine operation.
If the ECM detects the DTC ”P0110”, it operates the fail safe
function in which the intake air temp. is assumed to be 20°C
(68°F).
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 nand−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
DI0TE−03

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Intake Air Temp. Sensor
E6
E67
9ECM
5 V
THA
E2R
Y−G
BR−B 2
1E6
E69 12
E1 (M/T) (A/T) (M/T) (A/T)
DI−28
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
If DTCs P0110, P0115 and P0120 are output simultaneously, E2 (Sensor Ground) may be open.
1 Connect OBD II scan tool or TOYOTA hand−held tester and read value of intake
air temp.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand−held tester to DLC3.
(b) Turn the ignition switch ON and push the 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, 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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P19555
A00046
Intake Air Temp.
Sensor
7
1ECM
12
9
E6
E6THA
E25 V
E1
ON
E6
E69 2
(M/T) (A/T)
− DIAGNOSTICSENGINE (3RZ−FE)
DI−29
1996 TOYOTA T100 (RM449U)
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the intake air temp. sensor connector.
(b) Connect the sensor wire harness terminals together.
(c) Turn the 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 intake air temp. sensor.
NG

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P19553
P19698
P19673
A00047
Intake Air Temp.
Sensor
12 ON
7
9
9 12
THA E2
THA E2ECM
(M/T) (A/T)THA
E25 V
E1 E6
For M/T
For A/T
E6 E6E6
DI−30
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
3 Check for open in harness or ECM.
PREPARATION:
(a) Remove the right cowl side trim (See page MF−50).
(b) Connect between terminals THA and E2 of the ECM con-
nector.
HINT:
The intake air temp. sensor connector is disconnected. Before
checking, do a visual and contact pressure check for the ECM
connector (See page DI−3).
(c) Turn the 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.

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P19554
A00048
Intake Air Temp.
Sensor
7
1ECM
12
9
E6
E6THA
E25 V
E1
ON
E69 2
E6
(M/T)(A/T)
− DIAGNOSTICSENGINE (3RZ−FE)
DI−31
1996 TOYOTA T100 (RM449U)
4 Check for short in harness and ECM.
PREPARATION:
(a) Disconnect the intake air temp. sensor connector.
(b) Turn the 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 intake air temp. sensor.
NG

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FI7056
P19785
P19798
A00049
Intake Air Temp.
SensorON
ECM
THA
E25 V
E1
For M/T
For A/TE6 Connector
E6 Connector
DI−32
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
5 Check for short in harness or ECM.
PREPARATION:
(a) Remove the right cowl side trim (See page MF−50).
(b) Disconnect the E6 connector of the ECM.
HINT:
The intake air temp. sensor connector is disconnected.
(c) Turn the 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.
NG
Check and replace ECM (See page IN−26 ).

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Engine Coolant Temp.
Sensor
E6
E64
9ECM
5 V
THW
E2 G−Y
BR−B 2
1E6
E69 4
E1
(M/T) (A/T) (M/T) (A/T)
− DIAGNOSTICSENGINE (3RZ−FE)
DI−33
1996 TOYOTA T100 (RM449U)
DTC P0115 Engine Coolant Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
A thermistor built into the engine coolant temp. sensor changes the resistance value according to the engine
coolant temp.
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−27.
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
DI0TF−03

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P19555
A00046
Engine Coolant
Temp. Sensor
1ECM
E6THW
E25 V
E1
ON
E6
2
(M/T) (A/T)E6 E6
44
99
DI−34
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
INSPECTION PROCEDURE
HINT:
If DTCs P0110, P0115 and P0120 are output simultaneously, E2 (Sensor Ground) may be open.
1 Connect OBD II scan tool or TOYOTA hand−held tester and read value of engine
coolant temp.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand−held tester to the DLC3.
(b) Turn the ignition switch ON and push the 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 engine coolant temp.
HINT:
If there is open circuit, OBD II scan tool or TOYOTA hand−held tester indicates − 40°C (− 40°F).
If there is open 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).
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the engine coolant temp. sensor connector.
(b) Connect the sensor wire harness terminals together.
(c) Turn the 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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P19553
P19699
P19674
A00050
12 ON
4
THW E2
THW E2ECM(M/T) (A/T)THW
E25 V
E1 E6
For M/T
For A/T
E6E6
Engine Coolant
Temp. Sensor
E694
9
− DIAGNOSTICSENGINE (3RZ−FE)
DI−35
1996 TOYOTA T100 (RM449U)
3 Check for open in harness or ECM.
PREPARATION:
(a) Remove the right cowl side trim (See page MF−50).
(b) Connect between terminals THW and E2 of the ECM con-
nector.
HINT:
The engine coolant temp. sensor connector is disconnected.
Before checking, do a visual and contact pressure check for the
ECM connector (See page DI−3).
(c) Turn the 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 THW,
repair or replace harness.
NG
Confirm good connection at ECM.
If OK, replace ECM.

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P19554
A00048
12 ON
4ECM
THW
E25 V
E1 E6 E6
Engine Coolant
Temp. Sensor
4
9
E6 E69
(M/T)(A/T)
DI−36
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
4 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the engine coolant temp. sensor connector.
(b) Turn the 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 engine coolant temp. sensor.
NG