1996 TOYOTA T100 lights

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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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w/o Tachometer
w/ Tachometer
DI0VF−02
Q08498
TOYOTA Hand−Held Tester
DLC3
− DIAGNOSTICSAUTOMATIC TRANSMISSION
DI−265
1996 TOYOTA T100 (RM449U)
PRE−CHECK
1. DIAGNOSIS SYSTEM
(a) Description
When troubleshooting OBD II vehicles, the only dif-
ference from the usual troubleshooting procedure
is that you connect to the vehicle an OBD II scan
tool complying with SAE J1978 or TOYOTA hand−
held tester, and read off various data output from
the vehicle’s ECM.
OBD II regulations require that the vehicle’s on−
board computer lights up the Malfunction Indicator
Lamp (MIL) on the instrument panel when the com-
puter detects a malfunction in the computer itself or
in drive system components which affect vehicle
emissions. In addition to the MIL lighting up when
a malfunction is detected, the applicable DTCs pre-
scribed by SAE J2012 are recorded in the ECM
memory.
(3RZ−FE: See page DI−13)
(5VZ−FE: See page DI−140)
If the malfunction only occurs in 3 trips, the MIL goes off but the
DTCs remain recorded in the ECM memory.
To check the DTCs, connect an OBD II scan tool or
TOYOTA hand−held tester to DLC3 on the vehicle.
The OBD II scan tool or TOYOTA hand−held tester
also enables you to erase the DTCs and check
freeze frame data and various forms of engine data
(For instruction book).
DTCs include SAE controlled codes and Manufac-
turer controlled codes.
SAE controlled codes must be set as prescribed by
the SAE, while Manufacturer controlled codes can
be set freely by the manufacturer within the pre-
scribed limits (See DTC chart on page DI−276).

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w/o Tachometer
w/ Tachometer
Q08498
TOYOTA Hand−Held Tester
DLC3
− DIAGNOSTICSAUTOMATIC TRANSMISSION
DI−267
1996 TOYOTA T100 (RM449U)
2. INSPECT DIAGNOSIS (NORMAL MODE)
(a) Check the MIL.
(1) The MIL comes on when the ignition switch is turned
ON and the engine is not running.
HINT:
If the MIL does not light up, troubleshoot the combination meter
(See page BE−38).
(2) When the engine is started, the MIL should go off.
If the lamp remains on, the diagnosis system has
detected a malfunction or abnormality in the sys-
tem.
(b) Check the DTC.
NOTICE:
TOYOTA hand−held tester only: When the diagnostic sys-
tem is switched from normal mode to check mode, it erases
all DTCs and freezed frame data recorded in normal mode.
So before switching modes, always check the DTCs and
freezed frame data, and note them down.
(1) Prepare an OBD II scan tool (complying with SAE
J1978) or TOYOTA hand−held tester.
(2) Connect the OBD II scan tool or TOYOTA hand−
held tester to DLC3 at the lower of the instrument
panel.
(3) Turn the ignition switch ON and turn the OBD II scan
tool or TOYOTA hand−held tester switch ON.
(4) Use the OBD II scan tool or TOYOTA hand−held
tester to check the DTCs and freezed frame data
and note them down (For operating instructions,
see the OBD II scan tool’s instruction book).
(5) See page DI−276 to confirm the details of the
DTCs.
NOTICE:
When simulating symptoms with an OBD II scan tool (ex-
cluding TOYOTA hand−held tester) to check the DTCs, use
normal mode. For codes on the DTCs chart subject to ”2
trip detection logic”, turn the ignition switch off after the
symptoms have been simulated the 1st time. Then repeat
the simulation process again. When the program has been
simulated twice, the MIL lights up and the DTCs are re-
corded in the ECM.

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DI−276
− DIAGNOSTICSAUTOMATIC TRANSMISSION
1996 TOYOTA T100 (RM449U)
DIAGNOSTIC TROUBLE CODE CHART
If a DTC is displayed during the DTC check, check the circuit listed for that code in the table below and pro-
ceed to the page given.
*:  ... MIL lights up
DTC No.
(See Page)Detection ItemTrouble AreaMIL *Memory
P0500
3RZ−FE:
(DI−92)
5VZ−FE:
(DI−226)
Vehicle Speed Sensor
Malfunction
(No.1 Vehicle Speed Sensor)Open or short in No.1 vehicle speed sensor circuit
No.1 vehicle speed sensor
Combination meter
ECM

P0710
(DI−287)Transmission Fluid Temperature
Sensor Malfunction
(ATF Temperature Sensor)Open or short in ATF temperature sensor circuit
ATF temperature sensor
ECM

P0750
(DI−289)Shift Solenoid A Malfunction
(Shift Solenoid Valve No.1)Shift solenoid valve No.1 is stuck open or closed
Valve body is blocked up or stuck
P0753
(DI−290)Shift Solenoid A Electrical
Malfunction
(Shift Solenoid Valve No.1)Open or short in shift solenoid valve No.1 circuit
Shift solenoid valve No.1
ECM

P0755
(DI−289)Shift Solenoid B Malfunction
(Shift Solenoid Valve No.2)Shift solenoid valve No.2 is stuck open or closed
Valve body is blocked up or stuck
P0758
(DI−290)Shift Solenoid B Electrical
Malfunction
(Shift Solenoid Valve No.2)Open or short in shift solenoid valve No.2 circuit
Shift solenoid valve No.2
ECM

P0770
(DI−294)Shift Solenoid E Malfunction
(Shift Solenoid Valve SL)Shift solenoid valve SL is stuck open or closed
Valve body is blocked up or stuck
Lock−up clutch

P0773
(DI−296)Shift Solenoid E Electrical
Malfunction
(Shift Solenoid Valve SL)Open or short in shift solenoid valve SL circuit
Shift solenoid valve SL
ECM

P1700
(DI−300)Vehicle Speed Sensor No.2
Malfunction
(No.2 Vehicle Speed Sensor)Open or short in No.2 vehicle speed sensor circuit
No.2 vehicle speed sensor
ECM

P1780
(DI−306)Park/Neutral Position Switch
MalfunctionShort in park/neutral position switch circuit
Park/neutral position switch
ECM


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*O/D Main Switch
Contacts go open with switch pushed in.
Contacts go closed with switch pushed once again.
*1: 3RZ−FE
*2: 5VZ−FEO/D OFF Indicator Light
(Combination Meter)
Integration
Relay Ignition Switch
R/B No.2 R/B No.2J/B No.1ECM
GAUGE
Battery AM1
IG1
ALT AM1B+
OD2 B−YB−OY−G
W W
WW 65
2222
2 1 199 2
3
1A
141
2O3
O3E4
C13 C12
IA3
875
6
Y−G
W−B
IC
*1
*2
*
O/D
Main
Switch
− DIAGNOSTICSAUTOMATIC TRANSMISSION
DI−311
1996 TOYOTA T100 (RM449U)
O/D Main Switch & O/D OFF Indicator Light Circuit
CIRCUIT DESCRIPTION
The O/D main switch contacts go open when the switch is pushed in and go closed when it is pushed out.
In O/D main switch at OFF position, the O/D OFF indicator light lights up, and the ECM prohibits shifting O/D.
WIRING DIAGRAM
DI0WD−02

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ON
O/D Main Switch
ON
OFFOFF
ON
DI−312
− DIAGNOSTICSAUTOMATIC TRANSMISSION
1996 TOYOTA T100 (RM449U)
INSPECTION PROCEDURE
O/D OFF indicator light does not light up:
1 Check operation of O/D main switch.
PREPARATION:
Turn the ignition switch ON.
CHECK:
(a) Check the O/D OFF indicator light when O/D main switch
is pushed in to ON.
(b) Check the O/D OFF indicator light when O/D main switch
is pushed again to OFF.
OK:
(a) O/D OFF indicator light goes off
(b) O/D OFF indicator light lights up
NG Go to step 4.
OK

Downloaded from www.Manualslib.com manuals search engine D11000
− DIAGNOSTICSAUTOMATIC TRANSMISSION
DI−317
1996 TOYOTA T100 (RM449U)
INSPECTION PROCEDURE
1 Check operation of stop light.
CHECK:
Check if the stop lights go on and off normally when the brake pedal is operated and released.
NG Check and repair stop light circuit.
OK
2 Check STP signal.
When using OBD II scan tool or TOYOTA hand−held tester:
PREPARATION:
(a) Connect an OBD II scan tool or TOYOTA hand−held tes-
ter to the DLC3.
(b) Turn the ignition switch ON and OBD II scan tool or TOY-
OTA hand−held tester main switch ON.
CHECK:
Read the STP signal on the TOYOTA hand−held tester.
OK:
Brake PedalSTP Signal
DepressedON
ReleaseOFF
When not using OBD II scan tool or TOYOTA hand−held tes-
ter:
PREPARATION:
Turn the ignition switch ON.
CHECK:
Check the voltage between terminal B/K of the ECM connector
and body ground.
OK:
Brake PedalVoltage
Depressed7.5 − 14 V
ReleaseBelow 1.5 V