1996 TOYOTA LAND CRUISER Workshop Manual

P22478
Battery
FL AM1
Fusible Link
1F6
B−L
2
2 2
2
3
4
AM1
R/B No.2
Junction
Connector (J4)
Y Y
IG Switch
4 2
1 B−W
B−YFuse Block
GAUGE
Y
B
B 6IH14
B−W Park/Neutral
Position Switch
3
2 G−R G−W
O
O
IH2
To A/T Indicator Light
(Combination Meter)
Starter
1
S1 E7
E7
E7
17
16
22 NSW
E1B+
E1 E1
L
2 ECM
W
EA26
B
B
B−R
65 3
2IH1
21
B−W
IH2
DI−108
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
DTC P1780 Park/Neutral Position Switch Malfunction
CIRCUIT DESCRIPTION
The park/neutral position switch goes on when the shift lever is in the N o\
r 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 ”N”, ”2” and ”\
L”
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
the 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 T OYOTA hand−held tester to confirm the PNP switch signal from ”CUR-
RENT DATA”.
WIRING DIAGRAM
DI5PV−02
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P24677
32
4
10 98 6
51
7
A00188
ON
NSW
(+)
(−)
BE6653
P24678
−
DIAGNOSTICS ENGINE
DI−109
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
1 Check park/neutral position switch.
PREPARATION:
Disconnect park/neutral position switch connector.
CHECK:
Check continuity between each terminal shown below when the
shift lever is positioned to each range.
OK:
Shift PositionTerminal No. to continuityTerminal No. to continuity
P4 − 75 − 6
R4 − 8−
N4 − 105 − 6
D4 − 9−
22 − 4−
L3 − 4−
NG Replace park/neutral position switch.
OK
2 Check voltage between terminal NSW of ECM connector and body ground.
PREPARATION:
Remove instrument panel speaker No.1 panel
(See page SF−65 ).
CHECK:
(a) Turn ignition switch ON.
(b) Measure voltage between terminal NSW of ECM connec-
tor and body ground when the shift lever is positioned to
the following positions.
OK:
Shift lever positionP or NL, 2, D or R
Voltage0 V9 − 14 V
OK Check and replace ECM (See page IN−28 ).
NG
Check for open and short in harness and
connector between ECM and park/neutral
position switch (See page IN−28).
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S00816
BatteryFusible
Link
F8F7
11
W−R
3EA2
W−R11 6
IG Switch B−R
Fuse BlockIGN B−L
22
22 2
2
EFI Main Relay
1
2
3 4
EFI R
−Y
EC
EB
B−R
1EB1
R
Y−R
Y−REA2IH1
22 7
BR−B E4
E7 E7 E7
IGSW
MRLY
+B
E1 B+
ECM
1
3
12
24FL AM2
FL MAIN
W R
R/B No.2 Y
DI−11 0
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
ECM Power Source Circuit
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, battery positive voltage is applied t\
o the coil, closing the contacts of
the EFI main relay (Marking: EFI) and supplying power to the terminals +B\
of the ECM.
WIRING DIAGRAM
DI5PX−02
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A00189
ON
E1 +B
(−) (+)
BE6653
P24679
A00190
ON
IGSW
(+)
(−)
BE6653
P24680
−
DIAGNOSTICS ENGINE
DI−111
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
1 Check voltage between terminals +B and E1 of the ECM connector.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel
(See page SF−65 ).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals +B and E1 of the ECM con-
nector.
OK:
Voltage: 9 − 14 V
OK Proceed to next circuit inspection shown on matrix chart (See page DI−19 ).
NG
2 Check for open in harness and connector between terminal E1 of ECM conne\
ctor and body ground (See page IN−28).
NG Repair or replace harness or connector.
OK
3 Check voltage between terminal IGSW of ECM connector and body ground.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel (See page SF−65 ).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals IGSW of ECM and body
ground.
OK:
Voltage: 9 − 14 V
OK Go to step 6.
NG
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P24681
DI−11 2
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
4 Check IGN fuse from fuse block.
NG Check for short in all the harness and
components connected to IGN fuse.
OK
5 Check ignition switch.
PREPARATION:
(a) Remove instrument lower finish panel.
(b) Remove instrument cluster finish center panel No.2.
CHECK:
Check continuity between terminals.
OK:
Shift PositionTerminal No. to continuityTerminal No. to continuity
LOCK−−
ACC3 − 4−
ON2 − 3 − 46 − 11
START1 − 2 − 45 − 6 − 11
NG Replace ignition switch.
OK
Check for open and short in harness and
connector between battery and ignition
switch and ECM.
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A00191
ONMRLY(+)
(−)
BE6653
P24682
−
DIAGNOSTICS ENGINE
DI−11 3
1996 LAND CRUISER (RM451U)
6 Check voltage between terminal MREL of ECM connector and body ground.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel
(See page SF−65 ).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminal MREL of ECM and body
ground.
OK:
Voltage: 9 − 14 V
NG Check and replace ECM.
OK
7 Check EFI fuse (Marking: EFI) (See page DI−105).
NG Check for short in all the harness and
components connected to EFI fuse.
OK
8 Check EFI main relay (Marking: EFI) (See page SF−54).
NG Replace EFI main relay (Marking: EFI).
OK
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DI−11 4
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
9 Check for open and short in harness and connector between terminal MREL of
ECM connector and body ground (See page IN−28).
NG Repair or replace harness or connector.
OK
Check for open and short in harness and
connector between terminal +B of ECM
connector and battery (See page IN−28 ).
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P22480
BatteryStarter
FL MAIN
FL AM2EFI
EFI Main Relay
IG Switch IG
ST
Park/Neutral
Position SwitchCircuit Opening
Relay
Fuel Pump Relay
Fuel Pump
From Crankshaft Position
Sensor Fuel Pump
Resistor
(STA Signal)
(NE Signal) MRLY
FC
STA
NE
Tr1
Tr2
ECM
IGN FPR
−
DIAGNOSTICS ENGINE
DI−11 5
1996 LAND CRUISER (RM451U)
Fuel Pump Control Circuit
CIRCUIT DESCRIPTION
In the diagram below, when the engine is cranked, current flows form terminal ST of the igni\
tion switch to
terminal STA of ECM (STA signal).
When the STA signal and NE signal are input to the ECM, Tr1 is turned ON, current flows to coil of the circuit
opening relay, the relay switches on, power is supplied to the fuel pump and the fuel\
pump operates.
While the NE signal is generated (engine running), the ECM keeps Tr1 ON (circuit opening relay ON) and
the fuel pump also keeps operating.
The fuel pump speed is controlled at 2 levels (high speed or low speed) b\
y the condition of the engine (start-
ing, light load, heavy load). When the engine starts (STA ON), Tr2 in the ECM is OFF, so battery voltage is
applied directry to the fuel pump. Fuel pump operates at high speed.
After the engine starts, during idling or light loads, since Tr2 goes ON, power is supplied to the fuel pump
via the fuel pump resistor.
Fuel pump operates at low speed.
DI5PY−02
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