TOYOTA T100 1996 Factory Service Manual

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DI−247
1996 TOYOTA T100 (RM449U)
DTC P1780 Park/Neutral Position Switch Malfunction
CIRCUIT DESCRIPTION
The park/neutral position switch goes on when the shift lever is in the N or P shift position. When it goes on
terminal NSW of the ECM is grounded to body ground via the starter relay, thus the terminal NSW voltage
becomes 0 V. When the shift lever is in the D, 2, L, or R position, the park/neutral position switch goes off,
so the voltage of ECM. Terminal NSW becomes battery voltage, the voltage of the ECM internal power
source. If the shift lever is moved from the N position to the D position, this signal is used for air−fuel ratio
correction and for idle speed control (estimated control), etc.
DTC No.DTC Detecting ConditionTrouble Area
P1780
2 or more switches are ON simultaneously for ”R”, ”N”, ”2”
and ”L” and position
(2 trip detection logic)
Short in park/neutral position switch circuit
Park/neutral position switch
ECMWhen driving under conditions (a) and (b) for 30 sec. or
more park/neutral position switch is ON (N position):
(2 trip detection logic)
(a) Vehicle speed: 70 km/h (44 mph) or more
(b) Engine speed: 1,500 ∼ 2,500 rpm
HINT:
After confirming DTC P1780 use the TOYOTA hand−held tester to confirm the PNP switch signal from ”CUR-
RENT DATA”.
WIRING DIAGRAM
Refer to DTC P1780 on page DI−247.
INSPECTION PROCEDURE
Refer to DTC P1780 on page DI−247.
DI0V9−01

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W
SwitchIG
W
W W W
Park/Neutral
Position Switch
Clutch Start
Cancel Switch
Clutch
Start
SwitchStarter
Relay
StarterECM
STA
E1 11 1 3
E4 E7
IE1(M/T)(A/T) IE1 IE1
IA3
IA3
EB1
B−W (M/T)
BatteryB−W B−WB−W
B−W
B−W
B−W
W−B (A/T) W−B
(M/T)
B−R
B−R
(M/T)B−R
(M/T)
(M/T)
B−R (M/T) W−B (M/T)B−Y
W
R/B
No.2B (M/T)B
B(A/T)
B−O B−O
(A/T)
IC
IC
21
S1
1 1 13 3 15
2
1
2 12 3
15
26
2 2
ALT AM1
141 3622
5
615
2 2(M/T)
(A/T) (A/T) DI−248
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
Starter Signal Circuit
CIRCUIT DESCRIPTION
When the engine is cranked, the intake air flow is slow, so fuel vaporization is poor. A rich mixture is therefore
necessary in order to achieve good startability. While the engine is being cranked, the battery positive volt-
age is applied to terminal STA of the ECM. The starter signal is mainly used to increase the fuel injection
volume for the starting injection control and after−start injection control.
WIRING DIAGRAM
DI0VA−01

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DI−249
1996 TOYOTA T100 (RM449U)
INSPECTION PROCEDURE
HINT:
This diagnostic chart is based on the premise that the engine is cranked normally. If the engine is not
cranked, proceed to the problem symptoms table on page DI−148.
TOYOTA hand−held tester:
1 Connect TOYOTA hand−held tester and check STA signal.
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 STA signal on the TOYOTA hand−held tester while starter operates.
OK:
Ignition Switch PositionONSTART
STA signalOFFON
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI−148).
NG
2 Check for open in harness and connector between ECM and starter relay (Mark-
ing: ST) (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 BE6653S04092S05027A00776
START
For M/T
For A/TSTA (+)
STA (+)
DI−250
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
OBD II scan tool (excluding TOYOTA hand−held tester):
1 Check voltage between terminal STA of ECM connector and body ground.
PREPARATION:
Remove the right cowl side trim (See page SF−61).
CHECK:
Measure voltage between terminal STA of ECM connector and
body ground, during engine cranking.
OK:
Voltage: 6 V or more
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI−148).
NG
2 Check for open in harness and connector between ECM and starter relay (See
page IN−26).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN−26).

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BatterySwitch IG
W
2 2
2 W−R
12 22
E4 E4
(M/T)(A/T)
ECM
W−R
W−R R−L
B−W B−RB−Y
W−RW−R
BRW−BB−Y
IGN
J/B No.1 1A 1C
317
8
8 7
IA3
EA14
9
4
3
12
R/B No.2EFI AM2
2 22 2
52 3
1 2
EFI
Relay
E7 E5
24 16
E1 +B
EAEB
EA1
− DIAGNOSTICSENGINE (5VZ−FE)
DI−251
1996 TOYOTA T100 (RM449U)
ECM Power Source Circuit
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, battery positive voltage is applied to the coil, closing the contacts of
the EFI main relay (Marking: EFI) and supplying power to terminal +B of the ECM.
WIRING DIAGRAM
DI0VB−01

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P24221
P24332A00126
ON
For M/T
For A/TE1 (−) +B (+)
E1 (−) +B (+)
DI−252
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
INSPECTION PROCEDURE
1 Check voltage between terminals + B and E1 of ECM connector.
PREPARATION:
(a) Remove the right cowl side trim (See page SF−61).
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between terminals + B and E1 of ECM con-
nector.
OK:
Voltage: 9 − 14 V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI−148).
NG
2 Check for open in harness and connector between terminal E1 of ECM and body
ground (See page IN−26).
NG Repair or replace harness or connector.
OK
3 Check EFI main relay (Marking: EFI) (See page SF−45).
NG Replace EFI main relay.
OK

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IGN Fuse
J/B No.1
− DIAGNOSTICSENGINE (5VZ−FE)
DI−253
1996 TOYOTA T100 (RM449U)
4 Check EFI fuse (See page DI−244, step 2).
NG Check for short in all harness and
components connected to EFI fuse.
OK
5 Check for open harness and connector between EFI main relay (Marking: EFI)
and battery, EFI main relay (Marking: EFI) and ECM (See page IN−26).
NG Repair or replace harness or connector.
OK
6 Check IGN fuse.
PREPARATION:
Remove the IGN fuse from the J/B No.1.
CHECK:
Check continuity of IGN fuse.
OK:
Continuity
NG Check for short in all harness and
components connected to IGN fuse.
OK

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− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
7 Check ignition switch (See page BE−12).
NG Replace ignition switch.
OK
Check for open in harness and connector be-
tween IG switch and EFI main relay, EFI main
relay and body ground (See page IN−26).

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EFI
AM2
AM1
ALT
BatteryIG Switch
IG2
IG1
STIGNEFI Relay
Circuit Opening Relay
Clutch Start
Cancel Switch
(M/T)
L1 L2
ECM Fuel Pump
FC
Tr
STA
NE
Starter
Park/Neutral
Position Switch
(A/T)
Relay Starter
Start Clutch
Switch
(M/T)Crankshaft From
Position
Sensor(STA Signal)
(NE Signal)
− DIAGNOSTICSENGINE (5VZ−FE)
DI−255
1996 TOYOTA T100 (RM449U)
Fuel Pump Control Circuit
CIRCUIT DESCRIPTION
The fuel pump is switched on (low voltage at terminal FC) when STA is on or while the NE signal is input to
the ECM.
In the diagram below, when the engine is cranked, current flows from terminal ST of the ignition switch to
the starter relay coil, the starter relay switches on and current flows to coil L1 of the circuit opening relay.
Thus the circuit opening relay switches on, power is supplied to the fuel pump and the fuel pump operates.
When the STA signal and NE signal are input to the ECM, Tr is turned ON, current flows to coil L2 of the circuit
opening relay, the relay switches on and the fuel pump operates.
While the NE signal is generated (engine running), the ECM keeps Tr ON (circuit opening relay ON) and the
fuel pump also keeps operating.
DI0VC−01

Downloaded from www.Manualslib.com manuals search engine A00651
ECM
EFI AM2 ALT
Battery
IG Switch
Park/
Switch
StarterOpening Relay
Clutch
Start
Switch
E01 FC 4 14
E7 E5
(M/T)(A/T)
G−Y13
IE1 G−YL
1 4
6
Circuit
8
W−B
BJ1
W−B
IC
IC2 W−RW−R
EA19
EA
6
B−WB−R
Relay
(M/T)
3
B−O
WB−W
3
2
22
2 RelayEFI
2 22
51
2
22
2
22 5 R/B
1 2 2
2 3
1 W
W
B−YIA3
IGN
B (M/T)
B
Neutral
Position
(A/T)
Fuel
PumpW−BBJ1 BJ2
BJ2W−B(w/ ABS)
(w/o ABS)
11
(w/ ABS)
(w/o ABS)
10 16
Clutch
Start
Switch
(M/T)Cancel
No.2Starter
J/B No.1
B−R
B−WB−W
B−W B−W
B−W
B−O
B
B−R
W−B
W−RW
B−Y
W 2
2W−B
AM1
23
151 5
1 36 873 17 1113
IC
EB1
S1
EA1IA3
IA31C1A
1
IE1
IE1
B−Y
W−R
W−B
2
2 5 6 4
1
13A/T
DI−256
− DIAGNOSTICSENGINE (5VZ−FE)
1996 TOYOTA T100 (RM449U)
WIRING DIAGRAM