1996 TOYOTA T100 heater

Downloaded from www.Manualslib.com manuals search engine − DIAGNOSTICSENGINE (5VZ−FE)
DI−133
1996 TOYOTA T100 (RM449U)
(b) Clear the DTC.
The following actions will erase the DTCs and freezed
frame data.
(1) Operating the OBD II scan tool (complying with SAE
J1978) or TOYOTA hand−held tester to erase the
codes (See the OBD II scan tool’s instruction book
for operating instructions.).
(2) Disconnecting the battery terminals or EFI fuse.
NOTICE:
If the TOYOTA hand−held tester switches the ECM from
normal mode to check mode or vice−versa, or if the igni-
tion switch is turned from ON to ACC or OFF during check
mode, the DTCs and freezed frame data will be erased.
4. FAIL−SAFE CHART
If any of the following codes is recorded, the ECM enters fail−safe mode.
DTC No.Fail−Safe OperationFail−Safe Deactivation Conditions
P0100Ignition timing fixed at 10° BTDCReturned to normal condition
P0110Intake air temp. is fixed at 20°C (68°F)Returned to normal condition
P0115Engine coolant temp. is fixed at 80°(176°F)Returned to normal condition
P0120VTA is fixed at 0°
Following condition must be repeated at least 2 times
consecutively
0.1 V  VTA  0.95 V
P0135
P0141Heater circuit in which an abnormality is detected is
turned offIgnition switch OFF
P0325
P0330Max. timing retardationIgnition switch OFF
P1300Fuel cutIGF signal is detected for 6 consective ignitions
5. CHECK FOR INTERMITTENT PROBLEMS
HINT:
TOYOTA HAND−HELD TESTER only:
By putting the vehicle’s ECM in check mode, 1 trip detection logic is possible instead of 2 trip detection logic
and sensitivity to detect open circuits is increased. This makes it easier to detect intermittent problems.
(a) Clear the DTCs (See step 3).
(b) Set the check mode (See step 3).
(c) Perform a simulation test (See page IN−16).
(d) Check the connector and terminal (See page IN−26).
(e) Handle the connector (See page IN−26).
6. BASIC INSPECTION
When the malfunction code is not confirmed in the DTC check, troubleshooting should be performed in the
order for all possible circuits to be considered as the causes of the problems. In many cases, by carrying
out the basic engine check shown in the following flow chart, the location causing the problem can be found
quickly and efficiently. Therefore, use of this check is essential in engine troubleshooting.
1 Is battery positive voltage 11 V or more when engine is stopped?
NO Charge or replace battery.

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DI−140
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
DIAGNOSTIC TROUBLE CODE CHART
SAE CONTROLLED
HINT:
Parameters listed in the chart may not be exactly the same as your reading due to the type of instrument
or other factors.
If a malfunction code is displayed during the DTC check in check mode, check the circuit for that code listed
in the table below. For details of each code, turn to the page referred to under the ’’See Page ’’ for the respec-
tive ’’DTC No.’’ in the DTC chart.
DTC No.
(See Page)Detection ItemTrouble AreaMIL*Memory
P0100
(DI−149)Mass Air Flow Circuit
MalfunctionOpen or short in mass air flow meter circuit
Mass air flow meter
ECM

P0101
(DI−153)Mass Air Flow Circuit
Range/Performance
Problem
Mass air flow meter
P0110
(DI−154)Intake Air Temp. Circuit
MalfunctionOpen or short in intake air temp. sensor circuit
Intake air temp. sensor
ECM

P0115
(DI−158)Engine Coolant Temp. Circuit
MalfunctionOpen or short in engine coolant temp. sensor circuit
Engine coolant temp. sensor
ECM

P0116
(DI−162)Engine Coolant Temp. Circuit
Range/Performance ProblemEngine coolant temp. sensor
Cooling system
P0120
(DI−163)Throttle/Pedal Position
Sensor/Switch ”A” Circuit
MalfunctionOpen or short in throttle position sensor circuit
Throttle position sensor
ECM

P0121
(DI−168)Throttle/Pedal Position
Sensor/Switch ”A” Circuit
Range/Performance Problem
Throttle position sensor
P0125
(DI−169)Insufficient Coolant Temp. for
Closed Loop Fuel ControlOpen or short in heated oxygen sensor (bank 1 sensor 1)
circuit
Heated oxygen sensor (bank 1 sensor 1)

P0130
(DI−172)Heated Oxygen Sensor Circuit
Malfunction (Bank 1 Sensor 1)Heated oxygen sensor
Fuel trim malfunction
P0133
(DI−175)Heated Oxygen Sensor Circuit
Slow Response
(Bank 1 Sensor 1)
Heated oxygen sensor
P0135
(DI−176)Heated Oxygen Sensor Heater
Circuit Malfunction
(Bank 1 Sensor 1)Open or short in heater circuit of heated oxygen sensor
Heated oxygen sensor
ECM

P0136
(DI−178)Heated Oxygen Sensor Circuit
Malfunction
(Bank 1 Sensor 2)
Heated oxygen sensor
P0141
(DI−176)Heated Oxygen Sensor Heater
Circuit Malfunction
(Bank 1 Sensor 2)
Same as DTC No. P0135
*:  MIL lights up

Downloaded from www.Manualslib.com manuals search engine P21242 FI7210
A00027
Atomosphere
CoverIdeal Air−Fuel Mixture
Exhaust GasFlange
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating(Ceramic)
Output Voltage
Richer  Air−fuel Ratio  Leaner
− DIAGNOSTICSENGINE (5VZ−FE)
DI−169
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 whereby its output voltage changes suddenly in the vicinity of the
stoichiometric air−fuel ratio. This characteristic 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) Throttle valve does not fully closed
(d) 140 sec. or more after starting engine
Open or short in heated oxygen sensor
(bank1 sensor 1) circuit
Heated oxygen sensor (bank 1 sensor 1)
DI0UN−01

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P24318
P24317A00109
ON
HT1 (+) HT2 (+)
HT1 (+)HT2 (+) For M/T
For A/T
DI−176
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
DTC P0135 Heated Oxygen Sensor Heater Circuit
Malfunction (Bank 1 Sensor 1)
DTC P0141 Heated Oxygen Sensor Heater Circuit
Malfunction (Bank 1 Sensor 2)
CIRCUIT DESCRIPTION
Refer to DTC P0125 on page DI−169.
DTC No.DTC Detecting ConditionTrouble Area
P0135
P0141
When heater operates, heater current exceeds 2.35 A
(2 trip detection logic)Open or short in heater circuit of heated oxygen sensor
Heated oxygen sensor heater
ECM
Heater current of 0.2 A or less when heater operates
(2 trip detection logic)
HINT:
Sensor 1 refers to the sensor closer to the engine body.
Sensor 2 refers to the sensor farther away from the engine body.
WIRING DIAGRAM
Refer to DTC P0125 on page DI−169.
INSPECTION PROCEDURE
1 Check voltage between terminals HT1, HT2 of ECM connector and body ground.
PREPARATION:
(a) Remove the right cowl side trim (See page SF−61).
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between terminals HT1, HT2 of ECM connec-
tor and body ground.
HINT:
Connect terminal HT1 to bank 1 sensor 1.
Connect terminal HT2 to bank 1 sensor 2.
OK:
Voltage: 9 − 14 V
OK Check and replace ECM (See page IN−26).
NG
DI0UQ−01

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DI−177
1996 TOYOTA T100 (RM449U)
2 Check resistance of heated oxygen sensor heater (See page SF−60).
NG Replace heated oxygen sensor.
OK
Check and repair harness or connector
between EFI main relay, heated oxygen
sensor and ECM (See page IN−26).

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ONAirbag Sensor Assembly
IG
2Acc
(+) (−)
AB0119AB0234H00351
ON
− DIAGNOSTICSSUPPLEMENTAL RESTRAINT SYSTEM
DI−397
1996 TOYOTA T100 (RM449U)
INSPECTION PROCEDURE
1 Preparation.
PREPARATION:
(a) Turn ignition switch to LOCK.
(b) Disconnect center airbag sensor assembly connector.
(c) Turn ignition switch ON. But do not start engine.
(d) Measure voltage between terminal IG
2 or ACC on con-
nector wire harness side of center airbag sensor assem-
bly and body ground, and operate electric system (defog-
ger, wiper, headlight, heater blower, etc.).
Voltage: 6 V − 11.5 V at IG
2 and ACC
(e) Turn electric system switch OFF.
(f) Turn ignition switch to LOCK.
(g) Remove voltmeter and connect center airbag sensor as-
sembly connector.
2 Does SRS warning light turn off?
PREPARATION:
(a) Turn ignition switch to LOCK.
(b) Connect steering wheel pad connector.
(c) Connect center airbag sensor assembly connector.
(d) Turn ignition switch ON.
CHECK:
Operate electric system (defogger, wiper, headlight, heater
blower, etc.), and check that SRS warning light goes off.
NO Check for DTCs. If a DTC is output, perform trou-
bleshooting for DTC. If a normal code is output,
replace center airbag sensor assembly.
YES
From results of above inspection, malfunctioning part can now be considered normal. To make
sure of this, use simulation method to check.

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P14635A03783
− ENGINE MECHANICAL (3RZ−FE)CYLINDER HEAD
EM−29
1996 TOYOTA T100 (RM449U)
8. REMOVE DISTRIBUTOR
NOTICE:
Pulling on or bending the cords may damage the conductor
inside.
(a) Disconnect the distributor connector.
(b) Remove the hold−down bolts and distributor.
(c) Remove the O−ring.
9. REMOVE WATER OUTLET
(a) Disconnect the radiator inlet hose.
(b) Disconnect the ECT sender gauge connector.
(c) Remove the 2 bolts, water outlet and gasket.
10. REMOVE THROTTLE BODY (See page MF−28)
11. DISCONNECT ENGINE WIRE
(a) Disconnect these connectors:
w/ A/C:
A/C compressor connector
Oil pressure sensor connector
ECT sensor connector
EGR gas temperature sensor connector
EGR VSV connector
(b) Remove the 2 bolts and disconnect engine wire from the
intake chamber.
(c) Disconnect the 5 engine wire clamps and engine wire.
(d) Disconnect these connectors:
Knock sensor connector
Crankshaft position sensor connector
Fuel pressure control VSV connector
(e) Disconnect the DLC1 from the bracket.
(f) Disconnect the 2 engine wire clamps.
(g) Remove the bolt and disconnect the engine wire.
12. DISCONNECT INJECTOR CONNECTORS
13. REMOVE CYLINDER HEAD REAR COVER
(a) Disconnect the heater water bypass hose.
(b) Remove the 3 bolts and the rear cover and gasket.

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P14628
Z15935
P14635
EM−58
− ENGINE MECHANICAL (3RZ−FE)CYLINDER HEAD
1996 TOYOTA T100 (RM449U)
22. INSTALL FUEL RETURN PIPE
(a) Install the fuel return pipe with the 2 bolts.
(b) Connect these hoses:
Fuel return hose to fuel pressure regulator
Fuel return hose to fuel return pipe
23. INSTALL INTAKE CHAMBER STAY
Install the intake chamber stay with the 2 bolts.
Torque: 20 N·m (200 kgf·cm, 14 ft·lbf)
24. INSTALL EGR VALVE AND VACUUM MODULATOR
(a) Install a new gasket, EGR valve and vacuum modulator
with the bolt and 2 nuts.
Torque:
Bolt: 8.5 N·m (85 kgf·cm, 74 in.·lbf)
Nut: 19 N·m (195 kgf·cm, 14 ft·lbf)
(b) Connect these hoses:
2 vacuum hoses to EGR VSV (with clamp)
Water bypass hose to water bypass pipe
(c) Install 2 new gaskets and EGR pipe with the bolt and 4
nuts.
Torque:
Bolt: 18 N·m (185 kgf·cm, 14 ft·lbf)
Nut A: 19 N·m (195 kgf·cm, 14 ft·lbf)
Nut B: 20 N·m (200 kgf·cm, 15 ft·lbf)
25. INSTALL CYLINDER HEAD REAR COVER
(a) Install a new gasket and rear cover with the 3 bolts.
Torque: 13.5 N·m (135 kgf·cm, 10 ft·lbf)
(b) Connect the heater water bypass pipe.
26. CONNECT INJECTOR CONNECTORS
27. CONNECT ENGINE WIRE
(a) Connect the engine wire to the intake manifold with the
bolt.
(b) Connect the 2 engine wire clamps.
(c) Connect the DLC1 to the bracket.
(d) Connect these connectors:
Fuel pressure control VSV connector
Knock sensor connector
Crankshaft position sensor connector
(e) Connect the 5 engine wire clamps.
(f) Connect the engine wire to the intake chamber with the
2 bolts.
(g) Connect these connectors:
EGR VSV connector
EGR gas temperature sensor connector