engine TOYOTA T100 1996 Factory Service Manual

Downloaded from www.Manualslib.com manuals search engine − DIAGNOSTICSENGINE (3RZ−FE)
DI−77
1996 TOYOTA T100 (RM449U)
8 Check EGR valve (See page MF−44).
NG Repair or replace.
OK
9 Check value of EGR gas temp. sensor.
PREPARATION:
(a) Connect the TOYOTA hand−held tester to the DLC3.
(b) Turn the ignition switch ON and push the TOYOTA hand−held tester main switch ON.
(c) Select the ”ACTIVE TEST” mode on the TOYOTA hand−held tester (EGR system ON).
(d) Race the engine at 4,000 rpm for 3 min.
CHECK:
Measure EGR gas temp. while racing engine at 4,000 rpm.
OK:
EGR gas temp. after 3 min.: 140°C (284°F) or more
NG Replace EGR gas temp. sensor.
OK
Check and replace ECM (See page IN−26).

Downloaded from www.Manualslib.com manuals search engine P24322
EGR Gas Temp. Sensor
Connector
BE6653
P24204
A00072
ON
Wire Harness Side
1 (−)2 (+)
DI−78
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
OBD II scan tool (excluding TOYOTA hand−held tester):
1 Check resistance of EGR gas temp. sensor.
PREPARATION:
Disconnect the EGR gas temp. sensor connector.
CHECK:
Measure resistance between terminals of EGR gas temp. sen-
sor connector.
OK:
Resistance: 600 kΩ or less
HINT:
If there is open circuit, ohmmeter indicates 720 kΩ or more.
NG Check and replace EGR gas temp. sensor (See
page MF−48).
OK
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the EGR gas temp. sensor connector.
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between terminals of EGR gas temp. sensor
wire harness side connector.
OK:
Voltage: 4.5 − 5.5 V
OK Go to step 4.
NG

Downloaded from www.Manualslib.com manuals search engine BE6653
P24202
P24203
A00073
THG (+)
THG (+) ON
For M/T
E2 (−)
E2 (−) For A/T
− DIAGNOSTICSENGINE (3RZ−FE)
DI−79
1996 TOYOTA T100 (RM449U)
3 Check for open in harness or ECM.
PREPARATION:
(a) Remove the right cowl side trim (See page MF−50).
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between terminals of THG and E2 of ECM
connector.
HINT:
The EGR gas temp. sensor connector is disconnected.
OK:
Voltage: 4.5 − 5.5 V
OK Open in harness between terminals E2 or THG.
Repair or replace harness.
NG
Confirm connection at ECM.
If OK, replace ECM.
4 Check connection of vacuum hose and EGR hose (See page EC−2).
NG Repair or replace.
OK

Downloaded from www.Manualslib.com manuals search engine BE6653
P21086
P21087
FI7205
FI7206
A00074
ON
For M/T
E7 Connector
EGR
For A/TOFF
ON
E7 Connector
OFF
ON
VSV is ONVSV is OFF
AirAir
EFEF
EGR
DI−80
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
5 Check VSV for EGR.
PREPARATION:
(a) Remove the right cowl side trim (See page MF−50).
(b) Disconnect the E7 connector of ECM.
(c) Turn the ignition switch ON.
CHECK:
Check VSV function:
(1) Connect between terminal EGR of ECM and body
ground (ON).
(2) Disconnect between terminal EGR of ECM and
body ground (OFF).
OK:
(1) VSV is ON:
Air flows from port E to port F.
(2) VSV is OFF:
Air does not flow from port E to port F.
OK Go to step 7.
NG
6 Check operation for VSV for EGR (See page MF−44).
NG Replace VSV for EGR.
OK
Check for open in harness and connector be-
tween R/B NO.2 and ECM (See page
IN−26).

Downloaded from www.Manualslib.com manuals search engine P24228
EGR Gas Temp. Sensor
Connector
− DIAGNOSTICSENGINE (3RZ−FE)
DI−81
1996 TOYOTA T100 (RM449U)
7 Check EGR vacuum modulator (See page EC−7).
NG Repair or replace.
OK
8 Check EGR valve (See page EC−7).
NG Repair or replace.
OK
9 Check resistance of EGR gas temp. sensor.
PREPARATION:
(a) Disconnect the EGR gas temp. sensor connector.
(b) Start the engine and warm it up.
(c) Disconnect the VSV connector for EGR.
(d) Race the engine at 4,000 rpm or 3 min.
CHECK:
Measure resistance of the EGR gas temp. sensor while racing
the engine at 4,000 rpm.
OK:
Resistance of EGR gas temp. sensor after 3 min.:
4.3 kΩ or less
HINT:
Resistance: 188.6 − 439.0 kΩ at 20°C (68°F)
NG Replace EGR gas temp. sensor.
OK
Check and replace ECM (See page IN−26).

Downloaded from www.Manualslib.com manuals search engine DI−82
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
DTC P0402 Exhaust Gas Recirculation Flow Excessive
Detected
CIRCUIT DESCRIPTION
Refer to DTC P0401 on page DI−72.
DTC No.DTC Detecting ConditionTrouble Area
P0402
EGR gas temp. sensor value is high during EGR cut−off when
engine is cold and vacuum is applied to port E
(2 trip detection logic)EGR valve stuck open
VSV for EGR open malfunction
Open in VSV circuit for EGR
Short in EGR gas temp. sensor circuit
ECM
EGR valve is always open (2 trip detection logic)
WIRING DIAGRAM
Refer to DTC P0401 on page DI−72.
SYSTEM CHECK DRIVING PATTERN
Refer to DTC P0401 on page DI−72.
INSPECTION PROCEDURE
TOYOTA hand−held tester:
1 Connect TOYOTA hand−held tester and read EGR gas temp. value.
PREPARATION:
(a) Connect the TOYOTA hand−held tester to the DLC3.
(b) Turn the ignition switch ON and push the TOYOTA hand−held tester main switch ON.
CHECK:
Read EGR gas temp. on the TOYOTA hand−held tester.
OK:
EGR gas temp.: 150°C (302°F) or less (Not immediately after driving)
HINT:
If there is a short circuit, the TOYOTA hand−held tester indicates 159.3°C (318.7°F).
OK Go to step 4.
NG
DI0TV−03

Downloaded from www.Manualslib.com manuals search engine BE6653
P19554
A00048
EGR Gas Temp.
SensorECM
THG
E25 V
E1
ON
E6 E6
E6 E62
1314
9
9
(M/T)(A/T)
BE6653
FI7056
P19785
P19798
A00049
EGR Gas Temp.
SensorECM
THG
E25 V
E1
For M/T
For A/TE6 Connector
E6 Connector
− DIAGNOSTICSENGINE (3RZ−FE)
DI−83
1996 TOYOTA T100 (RM449U)
2 Check for short in harness and ECM.
PREPARATION:
Disconnect the EGR gas temp. sensor connector.
CHECK:
Read EGR gas temp. on the TOYOTA hand−held tester.
OK:
EGR gas temp.: 3.1°C (37.6°F)
OK Replace EGR gas temp. sensor.
NG
3 Check for short in harness or ECM.
PREPARATION:
(a) Remove the glove compartment (See page MF−50).
(b) Disconnect the E6 connector of the ECM.
HINT:
The EGR gas temp. sensor is disconnected.
CHECK:
Read EGR gas temp. on the TOYOTA hand−held tester.
OK:
EGR gas temp.: 3.1°C (37.6°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 P24228
EGR Gas Temp. Sensor
Connector
DI−84
− DIAGNOSTICSENGINE (3RZ−FE)
1996 TOYOTA T100 (RM449U)
4 Check VSV for EGR (See page MF−44).
OK Check EGR valve (See page EC−7).
NG
5 Check operation of VSV for EGR (See page EC−7).
NG Replace VSV for EGR.
OK
Check for open in harness and connector be-
tween R/B No.2 and ECM (See page IN−26).
OBD II scan tool (excluding TOYOTA hand−held tester):
1 Check resistance of EGR gas temp. sensor.
PREPARATION:
Disconnect the EGR gas temp. sensor connector.
CHECK:
Measure resistance between terminals of EGR gas temp. sen-
sor connector.
OK:
Resistance: 2.5 kΩ or more
(Not immediately after driving)
HINT:
If there is short circuit, ohmmeter indicates 200 Ω or less.
NG Replace EGR gas temp. sensor.
OK

Downloaded from www.Manualslib.com manuals search engine − DIAGNOSTICSENGINE (3RZ−FE)
DI−85
1996 TOYOTA T100 (RM449U)
2 Check for short in harness and connector between EGR gas temp. sensor and
ECM (See page IN−26).
NG Repair or replace harness or connector.
OK
3 Check VSV for EGR (See page MF−44).
OK Check EGR valve (See page EC−7).
NG
4 Check operation of VSV for EGR (See page MF−44).
NG Replace VSV for EGR.
OK
5 Check for open in harness and connector between R/B N0.2 and ECM (See page
IN−26).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN−26).

Downloaded from www.Manualslib.com manuals search engine FI7081
Waveform of Oxygen Sensor
before CatalystNormal CatalystWaveform of Oxygen Sensor
after Catalyst
P25762
Engine Speed
2500 − 3000 rpm
Idling
IG SW OFF
Warmed up3 minutesCheckTime (1)(3)
(4)
(2) DI−86
− DIAGNOSTICSENGINE (3RZ−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)
TWC (Three−way catalytic converter)
Heated oxygen sensor (bank 1 sensor 1, 2)
CONFIRMATION ENGINE RACING PATTERN
DI0TW−02