1996 TOYOTA T100 change time

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DI−175
1996 TOYOTA T100 (RM449U)
DTC P0133 Heated Oxygen Sensor Circuit Slow
Response (Bank 1 Sensor 1)
CIRCUIT DESCRIPTION
Refer to DTC P0125 on page DI−169.
DTC No.DTC Detecting ConditionTrouble Area
P0133
Response time for heated oxygen sensor’s voltage output to
change from rich to lean, or from lean to rich, is 1 sec. or
more during idling after engine is warmed up
(2 trip detection logic)
Heated oxygen sensor
HINT:
Sensor 1 refers to the sensor closer to the engine body.
INSPECTION PROCEDURE
1 Are there any other codes (besides DTC P0133) being output?
YES Go to relevant DTC chart.
NO
Replace heated oxygen sensor.
DI0UP−01

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− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
DTC P0171 System too Lean (Fuel Trim)
DTC P0172 System too Rich (Fuel Trim)
CIRCUIT DESCRIPTION
Fuel trim refers to the feedback compensation value compared against the basic injection time. Fuel trim
includes short−term fuel trim and long−term fuel trim.
Short−term fuel trim is the short−term fuel compensation used to maintain the air−fuel ratio at its ideal
theoretical value. The signal from the heated oxygen sensor indicates whether the air−fuel ratio is RICH or
LEAN compared to the ideal theoretical value, triggering a reduction in fuel volume if the air−fuel ratio is rich,
and an increase in fuel volume if it is lean.
Long−term fuel trim is overall fuel compensation carried out long−term to compensate for continual deviation
of the short−term fuel trim from the central value due to individual engine differences, wear over time and
changes in the usage environment.
If both the short−term fuel trim and long−term fuel trim are LEAN or RICH beyond a certain value, it is
detected as a malfunction and the MIL lights up.
DTC No.DTC Detecting ConditionTrouble Area
P0171
When air fuel ratio feedback is stable after engine warming up,
fuel trim is considerably in error on RICH side
(2 trip detection logic)
Air intake (hose loose)
Fuel line pressure
Injector blockage
Heated oxygen sensor (bank 1 sensor 1) malfunction
Mass air flow meter
Engine coolant temp. sensor
P0172
When air fuel ratio feedback is stable after engine warming up,
fuel trim is considerably in error on LEAN side
(2 trip detection logic)
Fuel line pressure
Injector leak, blockage
Heated oxygen sensor (bank 1 sensor 1) malfunction
Mass air flow meter
Engine coolant temp. sensor
HINT:
When DTC P0171 is recorded, the actual air−fuel ratio is on the LEAN side. When DTC P0172 is re-
corded, the actual air−fuel ratio is on the RICH side.
If the vehicle runs out of fuel, the air−fuel ratio is LEAN and DTC P0171 is recorded. The MIL then
comes on.
If the total of the short−term fuel trim value and long−term fuel trim value is within ± 25 %, the system
is functioning normally.
INSPECTION PROCEDURE
1 Check air induction system (See page SF−5).
NG Repair or replace.
OK
DI0US−01

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DI−183
1996 TOYOTA T100 (RM449U)
DTC P0300 Random/Multiple Cylinder Misfire Detected
DTC P0301 Cylinder 1 Misfire Detected
DTC P0302 Cylinder 2 Misfire Detected
DTC P0303 Cylinder 3 Misfire Detected
DTC P0304 Cylinder 4 Misfire Detected
DTC P0305 Cylinder 5 Misfire Detected
DTC P0306 Cylinder 6 Misfire Detected
CIRCUIT DESCRIPTION
Misfire: The ECM uses the crankshaft position sensor and camshaft position sensor to monitor changes in
the crankshaft rotation for each cylinder.
The ECM counts the number of times the engine speed change rate indicates that misfire has occur-
red.When the misfire rate equals or exceeds the count indicating that the engine condition has deteriorated,
the MIL lights up.
If the misfire rate is high enough and the driving conditions will cause catalyst overheating, the MIL blinks
when misfiring occurs.
DTC No.DTC Detecting ConditionTrouble Area
P0300Misfiring of random cylinders is detected during any
particular 200 or 1,000 revolutionsIgnition system
Injector
Fuel line pressure
EGR*
Compression pressure
Valve clearance not to specification
Valve timing
Mass air flow meter
Engine coolant temp. sensor
P0301
P0302
P0303
P0304
P0305
P0306For any particular 200 revolutions for engine, misfiring is
detected which can cause catalyst overheating
(This causes MIL to blink)
For any particular 1,000 revolutions of engine, misfiring is de-
tected which causes a deterioration in emission
(2 trip detection logic)
*: Only for 2WD models with a load capacity of 0.5 ton and regular cab.
HINT:
When the 2 or more codes for a misfiring cylinder are recorded repeatedly but no Random Misfire
code is
recorded, it indicates that the misfires were detected and recorded at different times.
DI0UT−01

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KNK signal waveform
0.5 V
/Division
5 msec./Division
100 μsec./Division 0V
200 mV
/Division
0V DI−190
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
3 Check for open and short in harness and connector between EC1 connector and
knock sensor (See page IN−26).
HINT:
If DTC P0325 has changed to P0330, check the knock sensor circuit on the right bank side.
If DTC P0330 has changed to P0325, check the knock sensor circuit on the left bank side.
NG Repair or replace harness or connector.
OK
Replace knock sensor.
Reference INSPECTION USING OSCILLOSCOPE
With the engine racing (4,000 rpm), measure between
terminal KNK1, KNK2 of ECM and body ground.
HINT:
The correct waveform is as shown.
Spread the time on the horizontal axis, and confirm that
period of the wave is 141 μsec (Normal mode vibration
frequency of knock sensor: 7.1 kHz).
HINT:
If normal mode vibration frequency is not 7.1 kHz, the sensor
is malfunctioning.

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Waveform of Oxygen Sensor
before CatalystNormal Catalyst Waveform of Oxygen Sensor
after Catalyst
P25762
Engine Speed
2500 − 3000 rpm
Idling
IG SW OFF
Warmed up 3 minutes CheckTime (1)(3)
(4)
(2) DI−210
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
DTC P0420 Catalyst System Efficiency Below Threshold
CIRCUIT DESCRIPTION
The ECM compares the waveform of the oxygen sensor located before the catalyst with the waveform of
the oxygen sensor located after the catalyst to determine whether or not catalyst performance has deterio-
rated.
Air−fuel ratio feedback compensation keeps the waveform of the oxygen sensor before the catalyst repeat-
edly changing back and forth from rich to lean.
If the catalyst is functioning normally, the waveform of the oxygen sensor after the catalyst switches back
and forth between rich and lean much more slowly than the waveform of the oxygen sensor before the cata-
lyst.
But when both waveforms change at a similar rate, it indicates that catalyst performance has deteriorated.


DTC No.DTC Detecting ConditionTrouble Area
P0420
After engine and catalyst are warmed up, and while
vehicle is driven within set vehicle and engine speed range,
waveforms of heated oxygen sensors (bank 1 sensor 1, 2)
have same amplitude
(2 trip detection logic)Three−way catalytic converter
Open or short in heated oxygen sensor (bank 1 sensor 1, 2)
circuit
Heated oxygen sensor (bank 1 sensor 1, 2)
CONFIRMATION ENGINE RACING PATTERN
DI0UZ−01

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NORMALSHIFT SOLENOID NO.1
MALFUNCTIONING
Solenoid valveNo.1 No.2GearSHIFT SOLENOID NO.2
MALFUNCTIONINGBOTH SOLENOIDS
MALFUNCTIONINGSolenoid valve
No.1 No.2GearSolenoid valve
No.1 No.2GearGear when shift selector is
manually operated
D
2
LON
ONOFF
ON
ON
OFF
OFF OFF
ON
ONOFF
ON
ON OFF
ON
ON ONOFF1st
2nd
3rd
O/D
1st
2nd
3rd
1st
2ndX
X
X
X
X
X
X
X
XON
ON
OFF
OFFON
ON
ON3rd 3rd
O/D
3rd
3rd
1st
2ndX
X
X
X
X
X
X
X
X OFF
OFF
ON
ON OFF OFF
OFF
ON
ON1st
O/D
3rd1st O/D O/D
3rd
1st
1stO/D O/D O/D
O/D
3rd 3rd
3rd
1st
1st
X: MalfunctionsON
ON3rd
3rd
DI−290
− DIAGNOSTICSAUTOMATIC TRANSMISSION
1996 TOYOTA T100 (RM449U)
DTC P0753, P0758 Shift Solenoid A/B Electrical Malfunc-
tion (Shift Solenoid Valve No.1/No.2)
CIRCUIT DESCRIPTION
Shifting from 1st to O/D is performed in combination with ON and OFF of the shift solenoid valves No.1 and
No.2 controlled by ECM. If an open or short circuit occurs in either of the shift solenoid valves, the ECM con-
trols the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly (Fail safe func-
tion).
Fail safe function:
If either of the shift solenoid valve circuits develops an open or short, the ECM turns the other shift solenoid
ON and OFF to shift to the gear positions shown in the table below. The ECM also turns the shift solenoid
valve SL OFF at the same time. If both solenoids are malfunction, hydraulic control cannot be performed
electronically and must be done manually.
Manual shifting as shown in the following table must be done (In the case of a short circuit, the ECM stops
sending current to the short circuited solenoid).
HINT:
Check the shift solenoid valve No.1 when DTC P0753 is output and check the shift solenoid valve No.2 when
DTC P0758 is output.
DTC No.DTC Detecting ConditionTrouble Area
P0753
P0758
ECM checks for open or short circuit in shift solenoid valves
No.1 and No.2 circuit when it changes
ECM records DTC P0753 or P0758 if condition (a) or (b) is
detected once, but it does not light up MIL
After ECM detects condition (a) or (b) continuously 2 times or
more in one−trip, it causes MIL light up until condition (a) or (b)
disappears
After that, if ECM detects condition (a) or (b) once, it starts
lighting up MIL again:
(a) Solenoid resistance is 8 Ω or less (short circuit) when sole-
noid is energized
(b) Solenoid resistance is 100 kΩ or more (open circuit) when
solenoid is not energized
Open or short in shift solenoid valve No.1/No.2 circuit
Shift solenoid valve No.1/No.2
ECM
DI0VP−02

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BR3582F00010
RotorSpeed Sensor
Magnet
To ECU
+V
−VHigh Speed
Low Speed
CoilNS
− DIAGNOSTICSANTI−LOCK BRAKE SYSTEM
DI−341
1996 TOYOTA T100 (RM449U)
DTC 31 − 36 Speed Sensor Circuit
CIRCUIT DESCRIPTION
The speed sensor detects wheel speed and sends the ap-
propriate signals to the ECU. These signals are used to control
the ABS system. The front and rear rotors each have 48 serra-
tions.
When the rotors rotate, the magnetic field emitted by the perma-
nent magnet in the speed sensor generates an AC voltage.
Since the frequency of this AC voltage changes in direct propor-
tion to the speed of the rotor, the frequency is used by the ECU
to detect the speed of each wheel.

DTC No.DTC Detecting ConditionTrouble Area
31, 32, 33, 34
Detection of any of conditions 1 through 3:
1. At vehicle speed of 10 km/h (6 mph) or more, pulses are
not input for 15 sec.
2. Momentary interruption of speed sensor signal occurs at
least 7 times in time between switching the ignition
switch ON and switching it OFF.
3. Abnormal fluctuation of speed sensor signals with ve-
hicle speed 20 km/h (12 mph) or more.
4. An open is detected in speed sensor circuit for 0.6 sec.
Right front, left front, right rear, left rear speed sensor
Open or short in each speed sensor circuit
ECU
35
Speed sensor signal is not input for about 1 sec. while left
front and right rear speed sensor signals are being
checked with IG switch ON.Open in left front or right rear speed sensor circuit
ECU
36
Speed sensor signal is not input for about 1 sec. while right
front and left rear speed sensor signals are being checked
with IG switch ON.Open in right front or left rear speed sensor circuit
ECU
HINT:
DTC No. 31 is for the right front speed sensor.
DTC No. 32 is for the left front speed sensor.
DTC No. 33 is for the right rear speed sensor.
DTC No. 34 is for the left rear speed sensor.
Fail safe function:
If trouble occurs in the speed sensor circuit, the ECU cuts off current to the ABS control (solenoid) relay and
prohibits ABS control.
DI10D−02

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− DIAGNOSTICSANTI−LOCK BRAKE SYSTEM
1996 TOYOTA T100 (RM449U)
DTC 43 Malfunction in Deceleration Sensor
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
43
Either of following 1 or 2 is detected:
1. After the battery terminal is connected, input from the
deceleration sensor does not change at one cycle (0
km/h → more than 30 km/h → 0 km/h) for 16 times con-
tinuously.
2. When the brake pedal is not depressed at vehicle speed
of 5 km/h or more, forward and backward G (more than
0.4 G) is detected for 30 seconds or more.
Deceleration sensor
Wire harness for deceleration sensor system
ECU
INSPECTION PROCEDURE
1 Check deceleration sensor (See page DI−321).
NG Replace deceleration sensor.
OK
2 Check for open or short in harness and connector between sensor and ECU
(See page IN−26).
NG Repair or replace harness or connector.
OK
Check and replace ABS ECU.
DI10K−01