TOYOTA LAND CRUISER 1996 J80 Workshop Manual

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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BE6053P24662A08533
OFF
(−) (+)
KNK 1
KNK 2E5 Connector
DI−60
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
HINT:
DTC P0325 is for the knock sensor circuit on the front side.
DTC P0330 is for the knock sensor circuit on the rear side.
1 Check continuity between terminal KNK1, KNK2 of ECM connector and body
ground.
PREPARATION:
(a) Remove the instrument panel speaker No.1 panel (See
page SF−65 ).
(b) Disconnect the E5 connector of ECM.
CHECK:
Measure resistance between terminal KNK1, KNK2 of ECM
connector and body ground.
HINT:
Connect terminal KNK1 to knock sensor 1.
Connect terminal KNK2 to knock sensor 2.
OK:
Resistance: 1 MΩ or higher
OK Go to step 3.
NG
2 Check knock sensor (See page SF−62 ).
NG Replace knock sensor.
OK
3 Check for open and short in harness and connector between ECM and knock sensor (See page IN−28 ).
NG Repair or replace harness or connector.
OK
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A00068
Knock signal waveform
0.5V/
Division
0.5V/
Division 0V
0V 5 m sec./Division
200
sec./Division
−
DIAGNOSTICS ENGINE
DI−61
1996 LAND CRUISER (RM451U)
4 Does malfunction disappear when a good knock sensor is installed?
YES Replace knock sensor.
NO
Check and replace ECM (See page IN−28 ).
Reference: INSPECTION USING OSCILLOSCOPE
With the engine racing (4,000 rpm) measure between ter-
minals KNK1, KNK2 of ECM and body ground.
HINT:
The correct waveform is as shown.
Spread the time on the horizontal axis, and confirm that
period of the wave is 164 μ sec. (Normal mode vibration
frequency of knock sensor: 6.1 kHz).
HINT:
If normal mode vibration frequency is not 6.1 kHz the sensor is
malfunctioning.
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S06273
E1
1
G−
2
BR
L
L G1
NE2
NE2−
12
E6
3
2
Distributor
Crankshaft Position Sensor G2
ECM
NE
4
1 L
L
G W
R
E6
E6
E6
E6
E6 11
10 4
56
DI−62
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
DTC P0335 Crankshaft Position Sensor ”A” Circuit Malfunction
CIRCUIT DESCRIPTION
The crankshaft position sensor (NE signal) consists of a signal plate and pick up coil. The NE\
signal plate
has 24 teeth and is built into the distributor. When the camshaft rotates, the protrusion on the signal plate
and the air gap on the pick up coil change, causing fluctuations in the magnetic field and generating an elec-
tromotive force in the pick up coil. The NE signal sensor generates 24 signals fo\
r every engine revolution.
The ECM detects the standard crankshaft angle based on the G1, G2 signals, \
detects the actual crankshaft
angle and the engine speed by the NE signals, and detects misfire by NE2 sign\
als.
DTC No.DTC Detecting ConditionTrouble Area
P0335
No crankshaft position sensor signal (NE signal) to ECM dur-
ing cranking.
(2 trip detection logic) Open or short in crankshaft position sensor circuit for NE
signal.
 Crankshaft position sensor for NE signal
 Starter
 ECM
No crankshaft position sensor signal (NE signal) to ECM with
engine speed 550 rpm or more (2 trip detection logic)
WIRING DIAGRAM
DI5PH−02
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P24663
1
23
4
(−) (+)
P23505
G, NE signal waveforms
20 m sec/Division (Idling) 5V/DIV
G1
G2
NE
NE2
−
DIAGNOSTICS ENGINE
DI−63
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
1 Check resistance of crankshaft position sensor for NE signal.
PREPARATION:
Remove the distributor cap and disconnect distributor connec-
tor.
CHECK:
Measure resistance between terminals 1 and 4 of distributor
connector.
OK:
Resistance
Cold185 − 275 Ω
Hot240 − 325 Ω
”Cold” is from − 10°C (14F° ) to 50°C (122°F) of engine coolant
temperature sensor and ”Hot” is from 50 °C (122° F) to 100° C
(212 °F).
Reference: INSPECTION USING OSCILLOSCOPE
During cranking or idling, check between terminals G1, G2, NE,
NE2 and G− of ECM.
HINT:
The correct waveforms are as shown.
NG Replace distributor housing assembly.
OK
2 Check for open and short in harness and connector between ECM and crank-\
shaft position sensor for NE signal (See page IN−28).
NG Repair or replace harness or connector.
OK
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