1996 TOYOTA T100 sensor

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− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
DTC P0116 Engine Coolant Temp. Circuit Range/
Performance Problem
CIRCUIT DESCRIPTION
Refer to DTC P0115 on page DI−33.
DTC No.DTC Detecting ConditionTrouble Area
P0116
When engine starts, water temp. is − 7°C (20°F) or less
And, 20 min. or more after engine starts, engine coolant
temp. sensor value is 20°C (68°F) or less
(2 trip detection logic)
Engine coolant temp. sensor
Cooling system
When engine starts, water temp. is between − 7°C (19.4°F)
and 10°C (50°F)
And, 5 min. or more after engine starts, engine coolant temp.
sensor value is 20°C (68°F) or less
(2 trip detection logic)
When engine starts, water temp. is 10°C (50°F) or more
And, 2 min. or more after engine starts, engine coolant temp.
sensor value is 20°C (68°F) or less
(2 trip detection logic)
INSPECTION PROCEDURE
HINT:
If DTCs P0115 and P0116 are output simultaneously, engine coolant temp. sensor circuit may be open.
Perform troubleshooting of DTC P0115 first.
1 Are there any other codes (besides DTC P0116) being output?
YES Go to relevant DTC chart.
NO
2 Check thermostat (See page CO−9).
NG Replace thermostat.
OK
Replace engine coolant temp. sensor (See
page MF−45).
DI0TG−03

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Throttle Position
SensorECM
VCC
VTA
IDL
E25 V
B+
− DIAGNOSTICSENGINE (3RZ−FE)
DI−39
1996 TOYOTA T100 (RM449U)
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 terminal IDL of the ECM becomes
0 V. At this time, a voltage of approximately 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 applied to terminal IDL of the
ECM. The voltage applied to terminal VTA of the ECM in-
creases 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 terminals 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
100 %100 %E2 line open
DI0TH−03

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Throttle Position Sensor
G−Y
11
2
3
4Y−L
BR−B Y1
E6 E6
E6 E6
E6 E6
E6 E611 1 0
12
11
995 V
B+ VCC
VTA
IDL
E2
E1 (M/T) (A/T)
* Closed Throttle
Position Switch *
FI7052
DI−40
− 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 the throttle
valve opening percentage.
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 the throttle valve opening percentage.
OK:
Throttle valveThrottle valve opening position
expressed as percentage
Fully openApprox. 75 %
Fully closedApprox. 10 %
OK Check for intermittent problems (See page
DI−3).

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P23808
A00051
ON
1 (+)
P23809
Throttle Position
Sensor
1
2
4
− DIAGNOSTICSENGINE (3RZ−FE)
DI−41
1996 TOYOTA T100 (RM449U)
NG
2 Check voltage between terminal 1 of wire harness side connector and body
ground.
PREPARATION:
(a) Disconnect the throttle position sensor connector.
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between terminals 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.
PREPARATION:
Disconnect the throttle position sensor connector.
CHECK:
Measure voltage between terminals 1, 2 and 4 of throttle posi-
tion sensor.
OK:
TerminalsThrottle valveResistance
1 − 4⎯2.5 − 5.9 kΩ
2 − 4Fully closed0.2 − 5.7 kΩ
2 − 4Fully open2.0 − 10.2 kΩ
NG Replace throttle position sensor.
OK

Downloaded from www.Manualslib.com manuals search engine BE6653
P23810
P23811
A00052
For M/TON
For A/TVTA (+) E2 (−)
VTA (+) E2 (−)
BE6653
P23812
P23813A00028
For M/TON
For A/TVCC (+)
VCC (+) E2 (−) E2 (−)
DI−42
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
4 Check voltage between terminals VTA and E2 of ECM connector.
PREPARATION:
(a) Remove the right cowl side trim (See page MF−50).
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between terminals VTA and E2 of ECM con-
nector.
OK:
Throttle valveVoltage
Fully closed0.3 − 0.8 V
Fully open2.7 − 5.2 V
NG Check for open and short in harness and
connector between ECM and throttle position
sensor (VTA line) (See page IN−26).
OK
Check and replace ECM (See page IN−26).
5 Check voltage between terminals VCC and E2 of ECM connector.
PREPARATION:
(a) Remove the right cowl side trim (See page MF−50).
(b) Turn the 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−26).
OK
Check for open in harness and connector be-
tween ECM and sensor (VCC line) (See page
IN−26).

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DI−43
1996 TOYOTA T100 (RM449U)
DTC P0121 Throttle/Pedal Position Sensor/Switch ”A”
Circuit Range/Performance Problem
CIRCUIT DESCRIPTION
Refer to DTC P0120 on page DI−39.
DTC No.Detection ItemTrouble Area
P0121
After vehicle speed has been exceeded 30 km/h (19 mph)
even once, output value of throttle position sensor is out of
applicable range while 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.
DI0TI−01

Downloaded from www.Manualslib.com manuals search engine P21242 FI7210
A00027
Atmosphere
Flange
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating (Ceramic)
Exhaust GasCoverIdeal Air−Fuel Mixture
Output Voltage
Richer − Air Fuel Ratio − Leaner DI−44
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
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 the exhaust gas, a three−way
catalytic 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 stoichiometric air−fuel ratio.
The oxygen sensor has the characteristic where by its output voltage changes suddenly in the vicinity of the
stoichiometric air−fuel ratio. This is used to detect the oxygen concentration 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 increases 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 is reduced and the oxygen sensor informs the ECM of the RICH condition (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 accurate 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 is low) current flows to the heater
to heat the sensor for accurate oxygen concentration detection.
DTC No.DTC Detecting ConditionTrouble Area
P0125
After engine is warmed up, heated oxygen sensor output
does not indicate RICH even once when conditions (a), (b),
(c) and (d) 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
(d) 140 sec. or more after starting engine
Open or short in heated oxygen sensor (bank 1 sensor 1)
circuit
Heated oxygen sensor (bank 1 sensor 1)
HINT:
After confirming DTC P0125 use the OBD II scan tool or TOYOTA handheld tester to confirm voltage output
of heated oxygen sensor from "CURRENT DATA".
If voltage output of heated oxygen sensor is 0 V, heated oxygen sensor circuit may be open or short.
DI0TJ−02

Downloaded from www.Manualslib.com manuals search engine P19611
R/B No.2
B−W
22E6 E6
E6
E6
BRE1 E1
EB
2
2
22
From Battery From
IG Switch
EFI RelayW−R
EFI2
1 5 13EA1
IE1 W−RW−RW−R 9
9
W−R
Heated
Oxygen
Sensor
(Bank 1
Sensor 2)2
13
423
14Heated
Oxygen
Sensor
(Bank 1
Sensor 1)
P−G
E7 E7
E7 E7
E7 E7 R−G WECM
OX1
HT1
OX2
E1
HT2E03
E03 (M/T)(A/T)6
2
5
14
155
3
13
24
16 B
To Body Ground
− DIAGNOSTICSENGINE (3RZ−FE)
DI−45
1996 TOYOTA T100 (RM449U)
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Connect OBD II scan tool or TOYOTA hand−held tester and read value for volt-
age output of heated oxygen sensor (Bank 1 sensor 1).
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand−held tester to the DLC3.
(b) Warm up the engine to normal operating temp.
CHECK:
Read voltage output of heated oxygen sensor (bank 1 sensor 1) when engine is suddenly raced.
HINT:
Perform quick racing to 4,000 rpm 3 times using the accelerator pedal.
OK:
Heated oxygen sensor (bank 1 sensor 1) output a RICH signal (0.45 V or more) at least once
OK Check and replace ECM (See page IN−26).
NG