1998 TOYOTA LAND CRUISER engine coolant

- DIAGNOSTICSENGINE
DI-147
340 Author
: Date
:
2004 LAND CRUISER (RM1071U)
DTC P0171 System too Lean (Bank 1)
DTC P0172 System too Rich (Bank 1)
DTC P0174 System too Lean (Bank 2)
DTC P0175 System too Rich (Bank 2)
CIRCUIT DESCRIPTION
The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim in-
cludes the short-term fuel trim and the long-term fuel trim.
The short-term fuel trim is the short-term fuel compensation used to maintain the air-fuel ratio at stoichio-
metric air-fuel ratio. The signal from the heated oxygen sensor indicates whether the air-fuel ratio is RICH
or LEAN compared to the stoichiometric air-fuel ratio. This variance triggers a reduction in the fuel volume
if the air-fuel ratio is RICH, and an increase in the fuel volume if it is LEAN.
The long-term fuel trim is the overall fuel compensation carried out in long-term to compensate for a continu-
al deviation of the short-term fuel trim from the central value, due to individual engine differences, wear over-
time and changes in the operating environment.
If both the short-term fuel trim and the long-term fuel trim are LEAN or RICH beyond a certain value, it is
detected as a malfunction and the MIL is illuminated and a DTC is set.
DTC No.DTC Detecting ConditionTrouble Area
P0171
P0174When air-fuel ratio feedback is stable after warming up engine,
fuel trim is considerably in error on LEAN side
(2 trip detection logic)
Air induction system
Injector blockage
Mass air flow meter
Engine coolant temperature sensor
Fuel pressure
Gas leakage in exhaust system
Open or short in heated oxygen sensor (bank 1, 2 sensor 1)
circuit
Heated oxygen sensor (bank 1, 2 sensor 1)
Heated oxygen sensor heater (bank 1, 2 sensor 1)
EFI or ECD relay
PCV piping
ECM
P0172
P0175When air-fuel ratio feedback is stable after warming up engine,
fuel trim is considerably in error on RICH side
(2 trip detection logic)
Injector leak, blockage
Mass air flow meter
Engine coolant temperature sensor
Ignition system
Fuel pressure
Gas leakage in exhaust system
Open or short in heated oxygen sensor (bank 1, 2 sensor 1)
circuit
Heated oxygen sensor (bank 1, 2 sensor 1)
ECM
DIC2A-01

- DIAGNOSTICSENGINE
DI-149
342 Author
: Date
:
2004 LAND CRUISER (RM1071U)
MONITOR STRATEGY
P0171Fuel system lean (Bank 1)
RltdDTCP0172Fuel system rich (Bank 1)Related DTCsP0174Fuel system lean (Bank 2)
P0175Fuel system rich (Bank 2)
Main sensors/componentsFront oxygen sensor
Required sensors/componentsRelated sensors/componentsEngine coolant temperature sensor, Mass air flow
meter, Crankshaft position sensor
Frequency of operationContinuous
Duration10 sec.
MIL operation2 driving cycles
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 voltage11 V-
Fuel system: Closed loop13 sec.-
One of the following conditions is met:A or B
A. Engine speed-1,000 rpm
B. Intake air amount per revolution0.26 g/sec.-
Warm up condition to enable air fuel ratio
learning controlConditions are met
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Following condition is continue for 3 sec.A or B
A. Smoothed fuel trim learning value (Lean)40% or more
B. Smoothed fuel trim learning value (Rich)-35% or less
WIRING DIAGRAM
Refer to DTC P0031 on page DI-49.

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-153
346 Author
: Date
:
2004 LAND CRUISER (RM1071U)
5 Check engine coolant temperature sensor.
PREPARATION:
Remove the engine coolant temperature sensor.
CHECK:
(a) Measure the resistance between the terminals of the en-
gine 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.
(b) Reinstall the engine coolant temperature sensor.
NG Repair or replace engine coolant temperature
sensor.
OK
6 Check for spark and ignition (See page IG-1).
NG Repair or replace ignition system.
OK

A09299A21418
Vehicle speed
(30 km/h)19 mph
IG SW OFF
Warm up
2 minutes 2 minutes 2 minutes
(
1)(
3)
(
4)
Idling(
2)(
3)
(
4)(
3) 3 to 5 minutes 3 to 5 minutes 3 to 5 minutes
(
4)
- DIAGNOSTICSENGINE
DI-159
352 Author
: Date
:
2004 LAND CRUISER (RM1071U)
14 Perform confirmation driving pattern.
(a) Disconnect the battery terminal and wait for a minute (clear learning value of the air fuel ratio). (
1)
(b) Connect the hand-held tester to the DLC3. (
1)
(c) Switch the hand-held tester from the normal mode to the check mode (See page DI-3). (
1)
(d) Start the engine and let it idle until engine coolant temperature is 75 °C (167 °F ) or more. (
2)
(e) Drive the vehicle at 19 mph (30 km/h) or more for 3 minutes or more. (
3)
(f) Let the engine idle for approx. 2 minutes. (
4)
(g) Perform steps (e) and (g) at least 3 times.
HINT:
If a malfunction exists, the MIL will be illuminated during step (f).
NOTICE:
If the conditions in this test are not strictly followed, detecting a malfunction may be difficult. If you
do not have a hand-held tester, turn the ignition switch OFF after performing steps (e) to (f), and then
do step (f) again.
GO
15 Is there DTC P0171, P0172, P0174 or P0175 being output again?
YES Replace ECM (See page SF-60) and perform
confirmation driving pattern (Refer to step 14).
NO

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.

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

DI-170
- DIAGNOSTICSENGINE
363 Author
: Date
:
2004 LAND CRUISER (RM1071U)
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 voltage8 V-
VVTNormal operation (i. e. not under scan-tool control)
Engine speed fluctuationEngine speed should not have changed rapidly
Engine speed (Two full revolutions (2 rev.)
after engine has started)400 rpm5,300 rpm
All of the following conditions are met:A, B and C
A. Engine coolant temperature-10C (14F)-
B. Either of the following conditions is met:(a) or (b)
(a) Intake air temperature-10C (14F)-
(b) Engine coolant temperature75C (167F)-
C. Either of the following conditions is
met:(a) or (b)
(a) Engine coolant temperature at engine
started-7C (19F)-
(b) Engine coolant temperature20C (68F)-
Intake air amount per revolution (varies
with engine speed)0.4 g/rev.-
Throttle position learningCompleted
Rapid throttle opening or closing operation has not occurred
Throttle position-Changing value of throttle position
Less than 0.5 per 0.008 sec.
Rough road counter-14 times/1,000 revolutions
(Not running on rough road)
For paired cylinder misfire (6 or 8 cylinders):
When ECT is between -10C (14F) and
75C (167F), the following conditions are
met:
A and B
A. Engine speed-3,000 rpm
B. Intake air amount per revolution at
1,800 rpm (varies with engine speed)0.7 g/sec.-
When ECT is over 75C (167F), the fol-
lowing conditions are met:A or (B and C)
A. NE signal plate tooth width learning was not completed
B. Engine speed-3,000 rpm
C. Intake air amount per revolution at
1,800 rpm (varies with engine speed)0.7 g/sec.-

DI-172
- DIAGNOSTICSENGINE
365 Author
: Date
:
2004 LAND CRUISER (RM1071U)
CONFIRMATION DRIVING PATTERN
(a) Connect the hand-held tester to the DLC3.
(b) Record DTC and the freeze frame data.
(c) Use the hand-held tester to set to the check mode (See page DI-3).
(d) Read the value on the misfire counter for each cylinder when idling. If the value is displayed on the
misfire counter, skip the following procedure of confirmation driving.
(e) Drive the vehicle several times with the engine speed, load and its surrounding range shown with EN-
GINE SPD, CALC LOAD in the freeze frame data or MISFIRE RPM, MISFIRE LOAD in the DATA LIST.
If you have no hand-held tester, turn the ignition switch OFF after the symptom is simulated once. Then re-
peat the simulation process again.
HINT:
In order to memorize the DTC of misfire, it is necessary to drive around MISFIRE RPM, MISFIRE LOAD in
the DATA LIST for the following period of time. Take care not to turn the ignition switch OFF. Turning the
ignition switch OFF switches the diagnosis system from check mode to normal mode. So all DTCs, etc., are
erased.
Engine SpeedTime
Idling3 minutes 30 seconds or more
1,000 rpm3 minutes or more
2,000 rpm1 minute 30 seconds or more
3,000 rpm1 minute or more
(f) Check if there is misfire and DTC and the freeze frame data. Record the DTC's, freeze frame data and
misfire counter data.
(g) Turn the ignition switch OFF and wait at least 5 seconds.
INSPECTION PROCEDURE
HINT:

If DTCs besides misfire DTCs are memorized simultaneously, troubleshoot the non-misfire DTCs first.

If the misfire does not occur when the vehicle is brought to the workshop, the misfire can be confirmed
by reproducing the condition of the freeze frame data. Also, after finishing the repair, confirm that there
is no misfire (See confirmation driving pattern).

On 6 and 8 cylinder engines, misfiring cylinder identification is disabled at high engine speed and only
a general misfire fault code P0300 is stored instead of a cylinder specific misfire fault code (P0301 to
P0308).
If the misfire starts in a high engine speed area or the misfire occurs only in a high engine speed area,
only code P0300 may be stored.
When only a general misfire fault code like P0300 is stored:

Erase the general misfire fault code from the hand-held tester or OBD II scan tool.

Start the engine and drive the confirmation patten.

Read the value of the misfire ratio for each cylinder. Or read the DTC.

Perform repairs on the cylinder that has a high misfire ratio. Or repair the cylinder indicated by the DTC.

After finishing repairs, drive the confirmation pattern again and confirm that no misfire occurs.

When either of SHORT FT #1, LONG FT #1, SHORT FT #2 or LONG FT #2 in the freeze frame data
is over the range of ±20 %, there is a possibility that the air-fuel ratio is becoming RICH (-20 % or
less) or LEAN (+20 % or more).

When COOLANT TEMP in the freeze frame data is less than 80°C (176°F), there is a possibility of
misfire only during engine warm-up.

If the misfire cannot be reproduced, the following reasons may apply: 1) the vehicle has low fuel, 2)
improper fuel is being used, and 3) the ignition plug is contaminated.