engine TOYOTA T100 1996 Factory Service Manual

Downloaded from www.Manualslib.com manuals search engine − DIAGNOSTICSENGINE (5VZ−FE)
DI−147
1996 TOYOTA T100 (RM449U) Symbols (Terminals No.)
Wiring ColorConditionSTD Voltage (V)
VTA (E6−7) − E2 (E6−22)Y−B ↔ BR−B
IG switch ON
Throttle valve fully closed0.3 − 0.8
IG switch ON
Throttle valve fully open3.2 − 4.9
G (E6−10) − G− (E6−11 )B ↔WIdlingPulse generation
(See page DI−191)
NE (E6−5) − NE− (E6−6)G ↔LIdlingPulse generation
(See page DI−191)
FPU (E5−9) − E1 (E5−16)R−B ↔BRIG switch ON9 − 14
Idling0 − 3.0
EGR* (E5−8) − E1 (E5−16)R−W ↔BRIG switch ON9 − 14
EVP1 (E5−15) − E1 (E5−16)W−G ↔BRIG switch ON9 − 14
THG* (E6−21) − E2 (E6−22)P ↔BR−BIG switch ON4.5 − 5.5
RSC (E7−22) − E1 (E5−16)B−R ↔BRIG switch ON, Disconnect E7 of ECM connector9 − 14
RSO (E7−23) − E1 (E5−16)BR−R ↔BRIG switch ON, Disconnect E7 of ECM connector9 − 14
OX1 (E6−13) − E1 (E5−16)W ↔BRMaintain engine speed at 2,500 rpm for 2 min. after
warming upPulse generation
(See page DI−172)
OX2 (E6−19) − E1 (E5−16)R ↔BRMaintain engine speed at 2,500 rpm for 2 min. after
warming upPulse generation
(See page DI−172)
HT1 (E7−15) − E03 (E7−1)P−G ↔W−BIdlingBelow 3.0
IG switch ON9 − 14
HT2 (E7−16) − E03 (E7−1)R−G ↔W−BIdlingBelow 3.0
IG switch ON9 − 14
KNK1 (E6−17) − E1 (E5−16)B ↔BRIdlingPulse generation
(See page DI−188)
KNK2 (E6−16) − E1 (E5−16)GR ↔BRIdlingPulse generation
(See page DI−188)
NSW (E7−14) − E1 (E5−16)B−O ↔BRIG switch ON, Other shift position in ”P”, ”N” position9 − 14
IG switch ON, Shift position in ”P”, ”N” position0 − 3.0
SP1 (E4−12) − E1 (E5−16)G ↔BRIG switch ON
Rotate driving wheel slowlyPulse generation
(See page DI−226)
TE1 (E5−5) − E1 (E5−16)V−W ↔BRIG switch ON9 − 14
W (E5−3) − E1 (E5−16)V ↔BRIdling9 − 14
IG switch ONBelow 3.0
ACV (E5−10) − E1 (E5−16)B−R ↔ BRIdling, A/C switch ON0 − 3
Idling, A/C switch OFF9 − 14
ACT (E4−5) − E1 (E5−16)L−B ↔BRA/C switch OFF at idlingBelow 2.0
A/C switch ON at idling5 or more
AC1 (E4−20) − E1 (E5−16)B−R ↔BRA/C switch ON at idlingBelow 2.0
A/C switch OFF at idling9 − 14
SDL (E4−18) − E1 (E5−16)W ↔BRDuring transmissionPulse generation
OD1 (E4−7) − E1 (E5−16)Y−R ↔BRIG switch ON9 − 14
THG* (E6−12) − E2 (E6−22)P ↔BR−BIG switch ON3.9 − 5.0
FC (E5−4) − E1 (E5−16)G−Y ↔BRIG switch ON9 − 14
Idling0 − 3.0
*: Only for 2WD models with a load capacity of 0.5 ton and regular cab.

Downloaded from www.Manualslib.com manuals search engine DI0UF−01
DI−148
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
PROBLEM SYMPTOMS TABLE
SymptomSuspect AreaSee page
Engine does not crank (Does not start)1. Starter and starter relayST−6
ST−14
No initial combustion (Does not start)
1. ECM power source circuit
2. Fuel pump control circuit
3. Engine control module (ECM)DI−251
DI−255
IN−26
No complete combustion (Does not start)1. Fuel pump control circuitDI−255
Engine cranks normally (Difficult to start)
1. Starter signal circuit
2. Fuel pump control circuit
3. CompressionDI−248
DI−255
EM−2
Cold engine (Difficult to start)1. Starter signal circuit
2. Fuel pump control circuitDI−248
DI−255
Hot engine (Difficult to start)1. Starter signal circuit
2. Fuel pump control circuitDI−248
DI−255
High engine idle speed (Poor idling)1. A/C signal circuit (Compressor circuit)
2. ECM power source circuitAC−79
DI−251
Low engine idle speed (Poor idling)1. A/C signal circuit (Compressor circuit)
2. Fuel pump control circuitAC−79
DI−255
Rough idling (Poor idling)1. Compression
2. Fuel pump control circuitEM−2
DI−255
Hunting (Poor idling)1. ECM power source circuit
2. Fuel pump control circuitDI−251
DI−255
Hesitation/Poor acceleration (Poor driveability)1. Fuel pump control circuit
2. A/T faultyDI−255
DI−282
Surging (Poor driveability)1. Fuel pump control circuitDI−255
Soon after starting (Engine stall)1. Fuel pump control circuitDI−255
During A/C operation (Engine stall)1. A/C signal circuit (Compressor circuit)
2. Engine control module (ECM)AC−79
IN−26

Downloaded from www.Manualslib.com manuals search engine DI0UG−01
FI6929
FI6972A00098
Power Transistor
Platinum Hot Wire
Output
Voltage Thermistor
AB
Platinum Hot Wire
Thermistor
B+
− DIAGNOSTICSENGINE (5VZ−FE)
DI−149
1996 TOYOTA T100 (RM449U)
CIRCUIT INSPECTION
DTC P0100 Mass Air Flow Circuit Malfunction
CIRCUIT DESCRIPTION
The mass air flow meter uses a platinum hot wire. the hot wire air flow meter consists of a platinum hot wire,
thermistor and a control circuit installed in a plastic housing. the hot wire air flow meter works on the principle
that the hot wire and thermistor located in the intake air bypass of the housing detect any changes in the
intake air temp.
The hot wire is maintained at the set temp. by controlling the current flow through the hot wire. This current
flow is ten measured as the output voltage of the air flow meter.
The circuit is constructed so that the platinum hot wire and thermistor provide a bridge circuit, with the power
transistor controlled so that the potential of A and B remains equal to maintain the set temp.
DTC No.Detection ItemDTCTrouble Area
P0100Open or short in mass air flow meter circuit with engine
speed 4,000 rpm or less
Open or short in mass air flow meter circuit
Mass air flow meter
ECM
P0100
Open or short in mass air flow meter circuit with engine
speed 4,000 rpm or more
(2 trip detection logic)
If the ECM detects DTC ”P0100” it operates the fail sefe function, keeping the ignition timing and injection
volume constant and making it possible to drive the vehicle.
HINT:
After confirming DTC P0100 use the OBD II scan tool or TOYOTA hand−held tester to confirm the mass air
flow ratio from ”CURRENT DATA”.
Mass Air Flow Value (gm/sec.)Malfunction
Approx. 0Mass air flow meter power source circuit open
VG circuit open or short
11.0 − 25.1 (idling after warming up)E3 circuit open

Downloaded from www.Manualslib.com manuals search engine P19917
From
IG Switch
Mass Air Flow MeterBattery
R/B No.2
J/B No.1B−W
W−R
B−YEFI
IGN
EFI RelayW−R
B−Y
W−B
EA1EA1
IE1
W−R W−R
1A1C
EA
1
2
222
2
12
2
2 3 2
4
17
31
2
52
E6 E6
E6 E68
818
GR−R
BR−W
(M/T)(A/T)
VG
E3
E1
W
9
9ECM
DI−150
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Connect OBD II scan tool or TOYOTA hand−held tester and read value of mass
air flow rate.
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand−held tester to the DLC3.
(b) Turn the ignition switch ON and push the OBD II scan tool or TOYOTA hand−held tester main switch
ON.
(c) Start the engine.
CHECK:
Read mass air flow rate on the OBD II scan tool or TOYOTA hand−held tester.
RESULT:
Type IType II
Mass air flow rata (gm/sec.)Approx. 011.0 − 25.1 (idling after warming up)
Type I Go to step 2.
Type II Go to step 5.

Downloaded from www.Manualslib.com manuals search engine BE6653
P24310A00099
ON
1 (+)
P23805
P24311A00100
For M/T
For A/TVG (+)
VG (+)
− DIAGNOSTICSENGINE (5VZ−FE)
DI−151
1996 TOYOTA T100 (RM449U)
2 Check voltage of mass air flow meter power source.
PREPARATION:
(a) Disconnect the mass air flow meter connector.
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between terminal 1 of mass air flow meter con-
nector and body ground.
OK:
Voltage: 9 − 14 V
NG Check for open in harness and connector
between EFI main relay and mass air flow meter
(See page IN−26).
OK
3 Check voltage between terminals VG of ECM connector and body ground.
PREPARATION:
(a) Remove the right cowl side trim (See page SF−61).
(b) Start the engine.
CHECK:
Measure voltage between terminal VG of ECM connector and
body ground while engine is idling.
OK:
Voltage:
1.1 − 1.5 V (P or N position and A/C switch OFF)
OK Check and replace ECM (See page IN−26).
NG

Downloaded from www.Manualslib.com manuals search engine P24313
P24312A00101
For M/T
For A/TE3
E3
DI−152
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
4 Check for open and short in harness and connector between mass air flow meter
and ECM (See page IN−26).
NG Repair or replace harness or connector.
OK
Replace mass air flow meter.
5 Check continuity between terminal E3 of ECM and body ground.
PREPARATION:
Remove the right cowl side trim (See page SF−61).
CHECK:
Check continuity between terminal E3 of ECM connector and
body ground.
OK:
Continuity (1 Ω or less)
NG Check and replace ECM (See page IN−26).
OK
6 Check for open in harness and connector between mass air flow meter and ECM
(See page IN−26).
NG Repair or replace harness or connector.
OK
Replace mass air flow meter.

Downloaded from www.Manualslib.com manuals search engine − DIAGNOSTICSENGINE (5VZ−FE)
DI−153
1996 TOYOTA T100 (RM449U)
DTC P0101 Mass Air Flow Circuit Range/Performance
Problem
CIRCUIT DESCRIPTION
Refer to DTC P0100 on page DI−149.
DTC No.DTC Detecting ConditionTrouble Area
P0101
After engine is warmed up, conditions (a) and (b) continue
with engine speed 900 rpm or less:
(2 trip detection logic)
(a) Throttle valve fully closed
(b) Mass air flow meter output  2.2 V
Mass air flow meterConditions (a) and (b) continue with engine speed 1,500 rpm or
more:
(2 trip detection logic)
(a) VTA  0.63 V
(b) Mass air flow meter output  1.06 V
INSPECTION PROCEDURE
1 Are there any other codes (besides DTC P0101) being output?
NO Replace mass air flow meter.
YES
Go to relevant DTC chart.
DI0UH−01

Downloaded from www.Manualslib.com manuals search engine FI4741
(fig. 1)
Acceptable
Resistance kΩ
− 20 0 20 40 60 80 100
(− 4) 32 68 104 140 176 212 30
20
10
5
3
2
1
0.5
0.3
0.2
0.1
Temp.°C (F°)
DI−154
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
DTC P0110 Intake Air Temp. Circuit Malfunction
CIRCUIT DESCRIPTION
The intake air temp. sensor is built into the mass air flow meter
and senses the intake air temp.
A thermistor built in the sensor changes the resistance value
according to the intake air temp.
The lower the intake air temp., the greater the thermistor resis-
tance value, and the higher the intake air temp., the lower the
thermistor resistance value (See fig. 1).
The intake air temp. sensor is connected to the ECM (See be-
low ). The 5 V power source voltage in the ECM is applied to the
intake air temp. sensor from the terminal THA via resistor R.
That is, the resistor R and the intake air temp. sensor are con-
nected in series. When the resistance value of the intake air
temp. sensor changes in accordance with changes in the intake
air temp., the potential at terminal THA also changes. Based on
this signal, the ECM increases the fuel injection volume to im-
prove driveability during cold engine operation.
If the ECM detects the DTC ”P0110”, it operates the fail safe
function in which the intake air temp. is assumed to be 20°C
(68°F).
DTC No.DTC Detecting ConditionTrouble Area
P0110Open or short in intake air temp. sensor circuit
Open or short in intake air temp. sensor circuit
Intake air temp. sensor
ECM
HINT:
After confirming DTC P0110 use the OBD II scan tool or TOYOTA hand−held tester to confirm the intake
air temp. from ”CURRENT DATA”.
Temp. DisplayedMalfunction
− 40°C ( − 40°F )Open circuit
140°C ( 284°F ) or moreShort circuit
DI0UI−01

Downloaded from www.Manualslib.com manuals search engine P19948
ECM
Intake Air Temp. Sensor
(Built into mass air flow meter)
3
4Y−G
BR−BE6
E6 E6E65 V
THA
E2 12 14
922
(M/T)(A/T)R
E1
− DIAGNOSTICSENGINE (5VZ−FE)
DI−155
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 value of
intake air temp.
PREPARATION:
(a) Connector the OBD II scan tool or TOYOTA hand−held tester to the DLC3.
(b) Turn the ignition switch ON and push the OBD II scan tool or TOYOTA hand−held tester main switch
ON.
CHECK:
Read temp. value on the OBD II scan tool or TOYOTA hand−held tester.
OK:
Same as actual intake air temp.
HINT:
If there is open circuit, OBD II scan tool or TOYOTA hand−held tester indicates − 40°C ( 40°F).
If there is short circuit, OBD II scan tool or TOYOTA hand−held tester indicates 140°C (284°F) or more.
NG − 40°C (− 40°F) ... Go to step 2.
140°C (284°F) or more ... Go to step 4.
OK
Check for intermittent problems
(See page DI−129).

Downloaded from www.Manualslib.com manuals search engine BE6653
P19555
A00046
ON
ECM Intake Air
Temp. Sensor
E2
E15 V
12 14
922THA3
4
E6 E6 E6
E6
(A/T) (M/T)
BE6653
P19553
P20223
P20199
A00102
For M/T
For A/TON
Intake Air
Temp. SensorECM
3
4
12 14
922
E2
E15 V
THA
E6 E6
E6 E6
THA E2
THA E2
(M/T)(A/T)
DI−156
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the mass air flow meter connector.
(b) Connect the sensor wire harness terminals together.
(c) Turn the ignition switch ON.
CHECK:
Read temp. value on the OBD II scan tool or TOYOTA
hand−held tester.
OK:
Temp. value: 140°C (284°F) or more
OK Confirm good connection at sensor. If OK,
replace mass air flow meter.
NG
3 Check for open in harness or ECM.
PREPARATION:
(a) Remove the right cowl side trim (See page SF−61).
(b) Connect between terminals THA and E2 of the ECM
connector.
HINT:
The mass air flow meter connector is disconnected.
Before checking, do a visual and contact pressure check for the
ECM connector (See page IN−26).
(c) Turn the ignition switch ON.
CHECK:
Read temp. value on the OBD II scan tool or TOYOTA
hand−held tester.
OK:
Temp. value: 140°C (284°F) or more
OK Open in harness between terminals E2 or THA,
repair or replace harness.
NG
Confirm good connection at ECM.
If OK, check and replace ECM.