Page 1211 of 3115
A21043
Starter Relay EFI Relay
Circuit Opening
Relay
Fuel Pump RelayMREL
FPRTr2
Tr1 EFI
IGNECM
FC
NE Fuel Pump
Battery
StarterFuel Pump Resistor
AM2Ignition Switch
STA
Crankshaft Position
Sensor (NE Signal) DI-162
- DIAGNOSTICSENGINE
355 Author: Date:
2004 LAND CRUISER (RM1071U)
DTC P0230 Fuel Pump Primary Circuit
CIRCUIT DESCRIPTION
In the diagram below, when the engine is cranked, current flows from terminal STAR of the ECM to the starter
relay coil and also current flows to terminal STA of the ECM (STA signal).
When the STA signal and NE signal are input to the ECM, the Tr1 is turned ON, current flows to the coil of
the circuit opening relay, the relay switches on, power is supplied to the fuel pump, and the fuel pump oper-
ates.
While the NE signal is generated (engine running), the ECM keeps the Tr1 ON (circuit opening relay ON)
and the fuel pump also keeps operating.
The fuel pump speed is controlled at two levels (high speed or low speed) by the condition of the engine
(starting, light load, heavy load). When the engine starts (STA ON), the Tr2 in the ECM is OFF, so the fuel
pump relay closes and battery positive voltage is applied directly to the fuel pump. The fuel pump operates
at high speed.
After the engine starts during idling or light loads, since the Tr2 goes ON, power is supplied to the fuel pump
via the fuel pump resistor. The fuel pump operates at low speed.
DIC2B-01
Page 1216 of 3115
- DIAGNOSTICSENGINE
DI-167
360 Author: Date:
2004 LAND CRUISER (RM1071U)
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
DTC P0307 Cylinder 7 Misfire Detected
DTC P0308 Cylinder 8 Misfire Detected
CIRCUIT DESCRIPTION
When a misfire occurs in the engine, hydrocarbons (HC) enter the exhaust in high concentrations. If this HC
concentration is high enough, there could be an increase in exhaust emissions levels. High concentrations
of HC can also cause to temperature of the catalyst to increase, possibly damaging the catalyst. To prevent
this increase in emissions and limit the possibility of thermal damage, the ECM monitors the misfire rate.
When the temperature of the catalyst reaches a point of thermal degradation, the ECM will blink the MIL.
For monitoring misfire, the ECM uses both the camshaft position sensor and the crankshaft position sensor.
The camshaft position sensor is used to identify misfiring cylinders and the crankshaft position sensor is used
to measure variations in the crankshaft rotation speed. The misfire counter increments when crankshaft rota-
tion speed variations exceed threshold values.
If the misfiring rate exceeds the threshold value and could cause emissions deterioration, the ECM illumi-
nates the MIL.
DIC2C-01
Page 1217 of 3115
A20646
20V
/Division Injector Signal Waveform
20V
/Division
GND
100 msec./Division (Idling)(Magnification)
GND
1 msec./Division (Idling)
Injection duration
DI-168
- DIAGNOSTICSENGINE
361 Author: Date:
2004 LAND CRUISER (RM1071U)DTC No.
DTC Detecting ConditionTrouble Area
P0300Misfiring of random cylinders is detected
Open or short in engine wire
Connector connection
Vacuum hose connection
P0301
P0302
P0303
P0304
P0305
P0306
P0307
P0308
Misfiring of each cylinder is detected
Vacuum hose connection
Ignition system
Injector
Fuel pressure
Mass air flow meter
Engine coolant temperature sensor
Compression pressure
Valve clearance
Valve timing
PCV piping
ECM
HINT:
When several codes for a misfiring cylinder are recorded repeatedly but no random misfire code is recorded,
it indicates that the misfires have been detected and recorded at different times.
Reference: Inspection using the oscilloscope.
With the engine idling, check the waveform between terminals #1 to #8 and E01 of the ECM connectors.
HINT:
The correct waveform is as shown.
Page 1218 of 3115
Crankshaft position sensor
(36-2 teeth or 12 teeth) Camshaft position sensor
ECM
A20490
- DIAGNOSTICSENGINE
DI-169
362 Author: Date:
2004 LAND CRUISER (RM1071U)
MONITOR DESCRIPTION
The ECM illuminates the MIL (2 trip detection logic) if:
The ECM will illuminate the MIL when the percent misfire exceeds the specified limit per 1,000 engine revolu-
tions. One occurrence of excessive misfire during engine start will set the MIL. Four occurrences are required
to set the MIL 1,000 revolutions after engine start.
The ECM blinks the MIL (MIL blinks immediately) if:
Within 200 engine revolutions at a high rpm, the threshold for ºpercent of misfire causing catalyst dam-
ageº is reached 1 time.
Within 200 engine revolutions at a normal rpm, the threshold for ºpercent of misfire causing catalyst
damageº is reached 3 time.
MONITOR STRATEGY
P0300Random/Multiple cylinder misfire detected
P0301Cylinder 1 misfire detected
P0302Cylinder 2 misfire detected
P0303Cylinder 3 misfire detected
Related DTCsP0304Cylinder 4 misfire detectedRelated DTCs
P0305Cylinder 5 misfire detected
P0306Cylinder 6 misfire detected
P0307Cylinder 7 misfire detected
P0308Cylinder 8 misfire detected
Rid / t
Main sensors/componentsCamshaft position sensor, Crankshaft position
sensor
Required sensors/components
Related sensors/componentsEngine coolant temperature sensor, Intake air
temperature sensor, Throttle position sensor
Frequency of operationContinuous
DurationEvery 1,000 revolutions (soon after engine is started: 1 time, other 4 times) (emission related misfire)
Every 200 revolutions (1 or 3 times) (catalyst deteriorating misfire)
MIL operation2 driving cycles MIL ON
Immediate MIL blinking (Catalyst deteriorating misfire)
Sequence of operationNone
Page 1234 of 3115
S01196S01699
30
20
10
5
3
02040 0.11
0.3
0.2 0.52
60 80 100 -20
(-4) (104) (140) (176)(32) (68) (212)
A21042
Ohmmeter
Acceptable
TEMPERATURE C (F)
RESISTANCE KW
- DIAGNOSTICSENGINE
DI-185
378 Author: Date:
2004 LAND CRUISER (RM1071U)
18 Check engine coolant temperature sensor.
PREPARATION:
Remove the engine coolant temperature sensor.
CHECK:
Measure the resistance between the terminals of the engine
coolant temperature sensor.
Resistance:
Tester ConnectionSpecified Condition
122.32 to 2.59 kW (20C (68F))1 - 20.310 to 0.326 kW (80C (176F))
NOTICE:
In case of checking the engine coolant temperature sensor
in the water, be careful not to allow water to go into the ter-
minals. After checking, dry the sensor.
HINT:
Alternate procedure: Connect an ohmmeter to the installed en-
gine coolant temperature sensor and read the resistance. Use
an infrared thermometer to measure the engine temperature in
the immediate vicinity of the sensor. Compare these values to
the resistance/temperature graph. Change the engine temper-
ature (warm up or allow to cool down) and repeat the test.
NG Replace
engine coolant temperature sensor.
OK
19 Switch step by number of misfire cylinder (Refer result of step 4).
High misfire rate cylinderProceed to
1 or 2 cylindersA
More than 3 cylindersB
B Go to step 5.
A
Check for intermittent problems
(See page DI-3).
Page 1235 of 3115
A00068
KNK Signal Waveform
0.5 V
Division
0.5 V/
Division0 V
0 V5 msec./Division
0.2 msec./Division DI-186
- DIAGNOSTICSENGINE
379 Author: Date:
2004 LAND CRUISER (RM1071U)
DTC P0325 Knock Sensor 1 Circuit (Bank 1 or Single
Sensor)
DTC P0330 Knock Sensor 2 Circuit (Bank 2)
CIRCUIT DESCRIPTION
Each knock sensor is fitted to the right bank and left bank of the cylinder block to detect engine knocking.
This sensor contains a piezoelectric element which generates a voltage when it becomes deformed. The
piezoelectric element sends a signal to the ECM, when the cylinder block vibrates due to knocking. If engine
knocking occurs, ignition timing is retarded to suppress it.
DTC No.DTC Detecting ConditionTrouble Area
P0325No signal of knock sensor 1 signal to ECM with engine speed
between 2,000 rpm and 5,400 rpmOpen or short in knock sensor 1 circuit
Knock sensor 1 (looseness)
ECM
P0330No signal of knock sensor 2 signal to ECM with engine speed
between 2,000 rpm and 5,400 rpmOpen or short in knock sensor 2 circuit
Knock sensor 2 (looseness)
ECM
HINT:
Bank 1 refers to the bank that includes cylinder No. 1.
Bank 2 refers the the bank that does not include cylinder No. 1.
Reference: INSPECTION USING OSCILLOSCOPE
With the engine racing (4,000 rpm), check the waveform
between terminals KNK1 and KNK2 of the ECM connec-
tor 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 0.13 msec. (Normal mode vibration
frequency of knock sensor: 8.1 kHz)
HINT:
If normal mode vibration frequency is not 8.1 kHz, the sensor
has malfunction.
DI1LQ-14
Page 1236 of 3115
- DIAGNOSTICSENGINE
DI-187
380 Author: Date:
2004 LAND CRUISER (RM1071U)
MONITOR DESCRIPTION
The knock sensor located on the cylinder block, detects spark knock.
When spark knock occurs, the sensor pick-up vibrates in a specific frequency range. When the ECM detects
the voltage in this frequency range, it retards the ignition timing to suppress the spark knock.
The ECM also senses background engine noise with the knock sensor and uses this noise to check for faults
in the sensor. If the knock sensor signal level is too low for more than 10 sec., and if the knock sensor output
voltage is out of normal range, the ECM interprets this as a fault in the knock sensor and sets a DTC.
MONITOR STRATEGY
RltdDTCP0325Knock sensor (Bank 1) range check or rationalityRelated DTCsP0330Knock sensor (Bank 2) range check or rationality
Main sensors/componentsKnock sensor
Required sensors/componentsRelated sensors/components
Crankshaft position sensor, Camshaft position
sensor, Engine coolant temperature sensor,
Mass air flow meter
Frequency of operationContinuous
Duration10 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever the follow-
ing DTCs are not presentSee ºList of disable a monitorº (on page DI-3)
Battery voltage10 V-
IdleOFF
Time after engine start5 sec.-
Engine coolant temperature60C (140F)-
Intake air amount per revolution0.45 g/rev-
Engine speed2,000 rpm5,400 rpm
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Sensor failure is indicated when the knock sensor output
level is below the specific threshold for:10 sec.
Page 1237 of 3115
A19967A20086
ECM
KNK1 1
E6 B2 K1
Knock Sensor 1
1
K2
Knock Sensor 21
2
KNK2 E6 EC1
EC *1: Shielded(*1)
3 EC1
W(*1)
B
W
J17
J/C
E
D
BRE
E
DBR
J17
J/C DI-188
- DIAGNOSTICSENGINE
381 Author: Date:
2004 LAND CRUISER (RM1071U)
WIRING DIAGRAM
