1996 TOYOTA LAND CRUISER Workshop Manual

DI−52
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
2 Check for heated oxygen sensor (bank 1 sensor 1) data.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the OBD II scan tool or TOYOTA hand−held tester to the DLC3.
(c) Warm up engine to normal operating temperature.
CHECK:
Read the heated oxygen sensor (bank 1 sensor 1) output voltage and sho\
rt −term fuel trim.
RESULT:
PatternHeated o xygen sensor (bank 1 sensor 1) output voltageShort−term fuel trim
1Lean condition (Changes at 0.55 V or less)Changes at about +20 %
2Rich condition (Changes at 0.4 V or more)Changes at about −20 %
3Except 1 and 2
3 Check for heated oxygen sensor
(bank 1 sensor 1) (See page SF−64 ).
1, 2
3 Check fuel pressure (See page SF−6 ).
NG Check and repair fuel pump, pressure
regulator, fuel pipe line and filter
(See page SF−1 ).
OK
4 Check injector injection (See page SF−29).
NG Replace injector.
OK
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−
DIAGNOSTICS ENGINE
DI−53
1996 LAND CRUISER (RM451U)
5 Check mass air flow meter and engine coolant temp. sensor
(See page SF−40 , SF−61 ).
NG Repair or replace.
OK
6 Check for spark and ignition (See page IG−1).
NG Repair or replace.
OK
Check and replace ECM (See page IN−28 ).
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DI−54
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
DTC P0300 Random/Multiple Cylinder Misfire Detected
DTC P0301 Cylinder 1 Misfire Detected
DTC P0302 Cylinder 2 Misfire Detected
DTC P0303 Cylinder 3 Misfire Detected
DTC P0304 Cylinder 4 Misfire Detected
DTC P0305 Cylinder 5 Misfire Detected
DTC P0306 Cylinder 6 Misfire Detected
CIRCUIT DESCRIPTION
Misfire: The ECM uses the crankshaft position sensor and camshaft position senso\
r to monitor changes in
the crankshaft rotation for each cylinder.
The ECM counts the number of times the engine speed change rate indicates that misfire has occurred.
When the misfire rate equals or exceeds the count indicating that the engine condition has deteriorat\
ed, the
MIL lights up.
If the misfire rate is high enough and the driving conditions will cause catalyst overheating, the MIL blinks
when misfiring occurs.
DTC No.DTC Detecting ConditionTrouble Area
P0300Misfiring of random cylinders is detected during the any partic-
ular 200 or 1,000 revolutions Ignition system
 Injector
 Fuel line pressure
 EGR
 Compression pressure
 Valve clearance not to specification
 Valve timing
 Mass air flow meter
 Engine coolant temp. sensor
P0301
P0302
P0303
P0304
P0305
P0306For any particular 200 revolutions of the engine, misfiring is
detected which can cause catalyst overheating
(This causes MIL to blink)
For any particular 1,000 revolutions of the engine, misfiring is
detected which causes a deterioration in emission
(2 trip detection logic)
HINT:
When the 2 or more codes for a misfiring cylinder are recorded repeatedly bu\
t no random misfire code is
recorded, it indicates that the misfires were detected and recorded at d\
ifferent times.
DI5PF−02
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P22424
Fusible Link
Battery
FL AM2
F7
EA2
6
11
3
1 IG Switch
W−RW
−R
B−R B−R
IH1
14B−R
B−R
B−R
B−R
B−R B−R 2
2
2
2
2
2 1
1
1
1
1
1 W−L
W−R
W−G Y
Y−R
Y−L
BR
BR E4
E4
E4
E4
E4 E4
E4
E4 11 12
25 2
1
15
13
26
EC
Injector #10
#20 #30
#40
#50
#60
E01
E02 ECM
No.1
No.2
No.3
No.4
No.5
No.6
FI6588 FI6538
A00064
10V/
Division
GND 10V/
Division
100 m sec./Division (Idling) GND(Magnification)
1 m sec./Division (Idling)
Injection duration
−
DIAGNOSTICS ENGINE
DI−55
1996 LAND CRUISER (RM451U)
WIRING DIAGRAM
Reference INSPECTION USING OSCILLOSCOPE
INJECTOR SIGNAL WAVEFORM
With the engine idling, measure between terminals #10 − #60 and E01 of ECM.
HINT:
The correct waveform is as shown.
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A00164P03792
P22893
DI−56
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
1 Check spark plug and spark of misfiring cylinder.
PREPARATION:
(a) Remove No.2 and No.3 cylinder head cover.
(b) Disconnect the high −tension cord from spark plug.
(c) Remove spark plug.
CHECK:
(a) Check the carbon deposits on electrode.
(b) Check electrode gap.
OK:
(1) No large carbon deposit present.
Not wet with gasoline or oil.
(2) Electrode gap: 0.8 mm (0.031 in.).
PREPARATION:
(a) Install the spark plug to the high −tension cord.
(b) Ground the spark plug.
(c) Disconnect injector connector.
CHECK:
Check if spark occurs while engine is being cranked.
NOTICE:
To prevent excess fuel being injected from the injectors
during this test, don’t crank the engine for more than 5 − 10
seconds at a time.
OK:
Spark jumps across electrode gap.
NG Replace or check ignition system (See page IG−1).
OK
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A00165
ON
#10 #20 #40 #50
#30 #60
BE6653
P24661
−
DIAGNOSTICS ENGINE
DI−57
1996 LAND CRUISER (RM451U)
2 Check voltage of ECM terminal for injector of failed cylinder.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel (See page
SF−65 ).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between applicable terminal of ECM connec-
tor and body ground.
OK:
Voltage: 9 − 14 V
OK Go to step 4.
NG
3 Check injector of misfiring cylinder (See page SF−29).
NG Replace injector.
OK
Check for open and short in harness and con-
nector between injector and ECM (See page
IN−28 ).
4 Check fuel pressure (See page SF−6 ).
NG Check and repair fuel pump, pressure regulator,
fuel pipe line and filter (See page SF−1).
OK
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DI−58
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
5 Check injector injection (See page SF−29).
NG Replace injector.
OK
6 Check EGR system (See page EC−11 ).
NG Repair EGR system.
OK
7 Check mass air flow meter and engine coolant temp. sensor (See page SF−40 ,
SF−61 ).
NG Repair or replace.
OK
Check engine mechanical systems compression pressure (See page EM−3), valve clearance
(See page EM−4) and valve timing (See page EM−13).
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P22425
Knock Sensor 1KNK2
Knock Sensor 2 KNK1
ECM
E1
E1
E5
E5
6
14
B
L−W
(On front side)
1
(On rear side) 1
−
DIAGNOSTICS ENGINE
DI−59
1996 LAND CRUISER (RM451U)
DTC P0325 Knock Sensor 1 Circuit Malfunction
DTC P0330 Knock Sensor 2 Circuit Malfunction
CIRCUIT DESCRIPTION
Knock sensors are fitted one each to the front and rear of the left side of t\
he cylinder block to detect engine
knocking. This sensor contains a piezoelectric element which generates a voltage \
when it becomes de-
formed, which occurs when the cylinder block vibrates due to knocking. If engin\
e knocking occurs, ignition
timing is retarded to suppress it.
DTC No.DTC Detecting ConditionTrouble Area
P0325No knock sensor 1 signal to ECM with engine speed, between
1,800 rpm and 5.200 rpmOpen or short in knock sensor 1 circuit
 Knock sensor 1 (looseness)
 ECM
P0330No knock sensor 2 signal to ECM with engine speed, between
1,800 rpm and 5.200 rpmOpen or short in knock sensor 2 circuit
 Knock sensor 2 (looseness)
 ECM
If the ECM detects the above DTCs, it operates the fail safe function in w\
hich the corrective retard angle value
is set to the maximum value.
WIRING DIAGRAM
DI5PG−02
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