1996 TOYOTA T100 engine

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DI−153
1996 TOYOTA T100 (RM449U)
DTC P0101 Mass Air Flow Circuit Range/Performance
Problem
CIRCUIT DESCRIPTION
Refer to DTC P0100 on page DI−149.
DTC No.DTC Detecting ConditionTrouble Area
P0101
After engine is warmed up, conditions (a) and (b) continue
with engine speed 900 rpm or less:
(2 trip detection logic)
(a) Throttle valve fully closed
(b) Mass air flow meter output  2.2 V
Mass air flow meterConditions (a) and (b) continue with engine speed 1,500 rpm or
more:
(2 trip detection logic)
(a) VTA  0.63 V
(b) Mass air flow meter output  1.06 V
INSPECTION PROCEDURE
1 Are there any other codes (besides DTC P0101) being output?
NO Replace mass air flow meter.
YES
Go to relevant DTC chart.
DI0UH−01

Downloaded from www.Manualslib.com manuals search engine FI4741
(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°)
DI−154
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
DTC P0110 Intake Air Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
The intake air temp. sensor is built into the mass air flow meter
and senses 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 resis-
tance 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 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 P0110 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
DI0UI−01

Downloaded from www.Manualslib.com manuals search engine P19948
ECM
Intake Air Temp. Sensor
(Built into mass air flow meter)
3
4Y−G
BR−BE6
E6 E6E65 V
THA
E2 12 14
922
(M/T)(A/T)R
E1
− DIAGNOSTICSENGINE (5VZ−FE)
DI−155
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) Connector 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 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 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−129).

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P19555
A00046
ON
ECM Intake Air
Temp. Sensor
E2
E15 V
12 14
922THA3
4
E6 E6 E6
E6
(A/T) (M/T)
BE6653
P19553
P20223
P20199
A00102
For M/T
For A/TON
Intake Air
Temp. SensorECM
3
4
12 14
922
E2
E15 V
THA
E6 E6
E6 E6
THA E2
THA E2
(M/T)(A/T)
DI−156
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the mass air flow meter 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 mass air flow meter.
NG
3 Check for open in harness or ECM.
PREPARATION:
(a) Remove the right cowl side trim (See page SF−61).
(b) Connect between terminals THA and E2 of the ECM
connector.
HINT:
The mass air flow meter connector is disconnected.
Before checking, do a visual and contact pressure check for the
ECM connector (See page IN−26).
(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, check and replace ECM.

Downloaded from www.Manualslib.com manuals search engine BE6653
P19554
A00048
ON
Intake Air
Temp. SensorECM
3
4
5 V
E2
12 14
922
E1
(A/T) (M/T)THA
E6
E6E6
E6
BE6653
FI7056
P19798
FI7034
A00103
ON
ECM Intake Air
Temp. Sensor
E2
E1
THA5 V
E6 Connector
E6 Connector
For M/T
For A/T
− DIAGNOSTICSENGINE (5VZ−FE)
DI−157
1996 TOYOTA T100 (RM449U)
4 Check for short in harness and ECM.
PREPARATION:
(a) Disconnect the mass air flow meter 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 mass air flow meter.
NG
5 Check for short in harness or ECM.
PREPARATION:
(a) Remove the right cowl side trim (See page SF−61).
(b) Disconnect the E6 connector of the ECM.
HINT:
The mass air flow meter 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).

Downloaded from www.Manualslib.com manuals search engine P19947
ECM
5 V
THW
E2 Engine Coolant Temp. Sensor
2
12
1 G−YG−Y
BR−BBR−B420
922
E1
(M/T)(A/T)E6E6
EC2
E6E6 EC2 DI−158
− DIAGNOSTICSENGINE (5VZ−FE)
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−154.
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
DI0UJ−01

Downloaded from www.Manualslib.com manuals search engine BE6653
P19555
A00046
ON
Engine Coolant
Temp. SensorECM
2
1
420
922
E2
E1 THW5 V
(A/T)
(M/T)E6
E6 E6E6
− DIAGNOSTICSENGINE (5VZ−FE)
DI−159
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−129).
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
P20224
P20200A00104
ON
Engine Coolant
Temp. Sensor
2
1ECM
THW E2
THW E2
5 V
E2
E1420
922THW
E6 E6
E6 E6
(A/T) (M/T)
For M/T
For A/T
BE6653
P19554
A00048
ON
Engine Coolant
Temp. Sensor
2
1
420
922
5 V
E2
E1 THW
ECM
(A/T) (M/T)E6
E6
E6
E6
DI−160
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
3 Check for open in harness or ECM.
PREPARATION:
(a) Remove the right cowl side trim (See page SF−61).
(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 IN−26).
(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, check and replace ECM.
4 Check for short in harness and 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