1998 TOYOTA LAND CRUISER injection

B14807
CO1B0-01
CO-14
- COOLINGRADIATOR
1775 Author
: Date
:
2004 LAND CRUISER (RM1071U)
RADIATOR
ON-VEHICLE CLEANING
INSPECT FINS FOR BLOCKAGE
If fins are clogged, wash them with water or a steam cleaner and
dry with compressed air.
NOTICE:

If the distance between the steam cleaner and the
core is too close, there is a possibility of damaging
the fin, so keep the following injection distance.
Injection PressureInjection Distance
2,942 - 4,903 kpa
(30 - 50 kg/cm2,
427 -711 psi)300 mm (11.811 in)
4,903 - 7,845 kpa
(50 - 80 kg/cm2,
711 - 1,138 psi)500 mm (19.685 in)

If the fins are bent, straighten them with a screwdriver
or pliers.

Never apply water directly onto the electronic compo-
nents.

P20302
FI7210
A00798
Atmosphere
Housing
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating (Ceramic)
Exhaust Gas CoverIdeal Air-Fuel Mixture
Output Voltage
Richer - Air Fuel Ratio - Leaner
A21040
Reference(Bank 1 Sensor 1 System Drawing) :
ECM
EFI or ECD Relay
EFI or ECD
Fuse No. 1 From
Battery
GroundOX1A
MREL HT1A
Duty
Control Heater
Sensor Heated Oxygen Sensor
EFI or ECD
Fuse No. 2
E2 DI-50
- DIAGNOSTICSENGINE
243 Author
: Date
:
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three-way cata-
lytic converter is used, but for the most efficient use of the three-way catalytic converter, the air-fuel ratio
must be precisely controlled so that it is always close to the stoichiometric air-fuel ratio.
The heated oxygen sensor has the characteristic which its output voltage changes suddenly in the vicinity
of the stoichiometric air-fuel ratio. This characteristic is used to detect the oxygen concentration in the ex-
haust gas and provide the ECM with feedback to control the air-fuel ratio.
When the air-fuel ratio becomes LEAN, the oxygen concentration in the exhaust increases and the heated
oxygen sensor informs the ECM of the LEAN condition (low voltage, i.e. less than 0.45 V).
When the air-fuel ratio is RICHER than the stoichiometric air-fuel ratio, the oxygen concentration in the ex-
haust gas is reduced and the heated oxygen sensor informs the ECM of the RICH condition (high voltage,
i.e. more than 0.45 V). The ECM judges by the voltage output from the heated oxygen sensor whether the
air-fuel ratio is RICH or LEAN and controls the injection time accordingly. However, if malfunction of the
heated oxygen sensor causes output of abnormal voltage, this disables the ECM for performing an accurate
air-fuel ratio control. The heated oxygen sensors include a heater which heats the zirconia element. The
heater is controlled by the ECM. When the intake air volume is low (the temperature of the exhaust gas is
low) current flows to the heater to heat the sensor for accurate oxygen concentration detection.
HINT:
The ECM provides a pulse width modulated control circuit to adjust current through the heater. The heated
oxygen sensor heater circuit uses a relay on the B+ side of the circuit.

FI6929A09074A09707
Power Transistor
Output
Voltage
AB B+
Temperature Sensor
Platinum Hot Wire
Temperature Sensor
Platinum Hot Wire
- DIAGNOSTICSENGINE
DI-57
250 Author
: Date
:
2004 LAND CRUISER (RM1071U)
DTC P0100 Mass or Volume Air Flow Circuit
DTC P0102 Mass or Volume Air Flow Circuit Low Input
DTC P0103 Mass or Volume Air Flow Circuit High Input
CIRCUIT DESCRIPTION
The Mass Air Flow (MAF) meter measures the amount of air flowing through the throttle valve. The ECM uses
this information to determine the fuel injection time and provide a proper air fuel ratio. Inside the MAF meter,
there is a heated platinum wire exposed to the flow of intake air.
By applying a specific current to the wire, the ECM heats this wire to a given temperature. The flow of incom-
ing air cools the wire and an internal thermistor, affecting their resistance. To maintain a constant current
value, the ECM varies the voltage applied to these components in the MAF meter. The voltage level is pro-
portional to the airflow through the sensor. The ECM interprets this voltage as the intake air amount.
The circuit is constructed so that the platinum hot wire and temperature sensor provide a bridge circuit, with
the power transistor controlled so that the potential of A and B remains equal to maintain the set temperature.
DTC No.DTC Detection ConditionTrouble Area
P0100Open or short in mass air flow meter circuit for more than 3
sec.
P0102Open or short in mass air flow meter circuit for more than 3
sec.
Open or short in mass air flow meter circuit

Mass air flow meter
P0103
Open in mass air flow meter circuit for more than 3 sec. (EVG
circuit)
Short in mass air flow meter circuit for more than 3 sec. (+B
circuit)
Mass air flow meter

ECM
DIC23-01

- DIAGNOSTICSENGINE
DI-65
258 Author
: Date
:
2004 LAND CRUISER (RM1071U)
DTC P0101 Mass or Volume Air Flow Circuit Range/
Performance Problem
CIRCUIT DESCRIPTION
Refer to DTC P0100, P0102 and P0103 on page DI-57.
DTC No.DTC Detecting ConditionTrouble Area
P0101
After engine is warmed up, conditions (a), (b), (c) and (d) con-
tinue for more than 10 seconds:
(2 trip detection logic)
(a) Throttle valve fully closed
(b) Voltage output of the mass air flow meter is more than 2.2
V.
(c) Engine coolant temperature is more than 70 °C (158 °F).
(d) Engine speed is less than 900 rpm.

Mass air flow meter
Conditions (a), (b) and (c) continue for more than 6 seconds
with engine speed: (2 trip detection logic)
(a) Engine speed is more than 0 rpm.
(b) VTA is more than 0.1 V.
(c) Voltage output of the mass air flow meter is less than 0.25
V.
MONITOR DESCRIPTION
The MAF (Mass Air Flow) meter helps the ECM calculate the amount of air flowing through the throttle valve.
The ECM uses this information to determine the fuel injection time and provide a proper air fuel ratio. Inside
the MAF meter, there is a heated platinum wire exposed to the flow of intake air. By applying a specific current
to the wire, the ECM heats this wire to a given temperature. The flow of incoming air cools the wire and an
internal thermistor, affecting their resistance. To maintain a constant current value, the ECM varies the volt-
age applied to these components in the MAF meter. The voltage level is proportional to the air flow through
the MAF meter. The ECM interprets this voltage as the intake air amount. If there is a defect in the MAF meter
or an open or short circuit, the voltage level will deviate outside the normal operating range. The ECM inter-
prets this deviation as a defect in the MAF meter and sets a DTC.
Example:
If the voltage is more than 2.2 V at idle or less than 0.25 V at idle OFF, the ECM interprets this as a defect
in the MAF meter and sets a DTC.
MONITOR STRATEGY
Related DTCsP0101Mass air flow meter rationality
Main sensors/componentsMass air flow meter
Required sensors/componentsRelated sensors/componentsEngine speed sensor, Engine coolant tempera-
ture sensor, Throttle position sensor
Frequency of operationContinuous
Duration10 sec. (High voltage)
6 sec. (Low voltage)
MIL operation2 driving cycles
Sequence of operationNone
DI1LC-17

A20314
Vehicle speed
40 km/h
(25 mph)
Ignition OFF
(a) (b)120 sec.
or more(d)
20 sec.
or more 20 sec.
or more20 sec.
or more20 sec.
or more
20 sec.
or more30 sec. (e)
(f) Idling (c)(d)
(d)
(e)
- DIAGNOSTICSENGINE
DI-109
302 Author
: Date
:
2004 LAND CRUISER (RM1071U)
CONFIRMATION DRIVING PATTERN
(a) Connect the hand-held tester to the DLC3.
(b) Switch the hand-held tester from the ºnormal modeº to the ºcheck modeº (See page
DI-3).
(c) Start the engine and let the engine idle for 120 seconds or more.
(d) Drive the vehicle at 25 mph (40 km/h) or more for 20 seconds or more.
(e) Let the engine idle for 20 seconds or more. Perform steps (d) and (e) at 3 times.
(f) Let the engine idle for 30 seconds.
HINT:
If a malfunction exists, the MIL will light up during step (f).
NOTICE:
If the conditions in this test are not strictly followed, detection of the malfunction will not be possible.
If you do not have a hand-held tester, turn the ignition switch OFF after performing steps (c) to (f),
then perform steps (c) to (f) again.
INSPECTION PROCEDURE
HINT:
Hand-held tester only:
The narrowing down the trouble area is possible by performing ACTIVE TEST of the following ºA/F CON-
TROLº (Heated oxygen sensor or another can be distinguished).
(a) Perform ACTIVE TEST by hand-held tester (A/F CONTROL).
HINT:
ºA/F CONTROLº is an ACTIVE TEST which changes the injection volume to -12.5 % or +25 %.
(1) Connect the hand-held tester to the DLC3 on the vehicle.
(2) Turn the ignition switch ON.
(3) Warm up the engine with the engine speed at 2,500 rpm for approximately 90 seconds.
(4) Select the item ºDIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROLº.
(5) Perform ºA/F CONTROLº with the engine in an idle condition (press the right or left button).
RESULT:
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume
+25% " rich output: More than 0.5 V
-12.5% " lean output: Less than 0.4 V

+25 %
-12.5 %
More than 0.5 V
Less than 0.4 V
Case 1
Case 2
Case 3
Case 4
Output voltage of heated oxygen
sensor (sensor 1: front sensor)
Injection volume
Output voltage
Output voltage of heated oxygen
sensor (sensor 2: rear sensor)Mainly suspect
trouble area
OK
+25 %
-12.5 %
More than 0.5 V
Less than 0.4 V
Injection volume
Output voltage
+25 %
-12.5 %
More than 0.5 V
Less than 0.4 V
Injection volume
Output voltage
Sensor 1: front sensor
(sensor 1, heater, sensor 1
circuit)
+25 %
-12.5 %
More than 0.5 V
Less than 0.4 V
Injection volume
Output voltage
+25 %
-12.5 %
Injection volume
Output voltage
NG
+25 %
-12.5 %
Injection volume
Output voltage
NG
+25 %
-12.5 %
Injection volume
Output voltage
NG
+25 %
-12.5 %
Injection volume
Output voltage
NGExtremely rich or lean of the
actual air-fuel ratio
(Injector, fuel pressure, gas
leakage in exhaust system,
etc.) OK
OK
OK
Almost no reaction
Almost no reaction
'
Sensor 2: rear sensor
(sensor 2, heater, sensor 2
circuit)
Almost no reaction Almost no reaction
DI-1 10
- DIAGNOSTICSENGINE
303 Author
: Date
:
2004 LAND CRUISER (RM1071U)
NOTICE:
However, there is a few seconds delay in the sensor 1 (front sensor) output. And there is about 20
seconds delay in the sensor 2 (rear sensor).
The following A/F CONTROL procedure enables the technician to check and graph the voltage output of
the heated oxygen sensors (sensor 1 and 2).
For displaying the graph indication, enter ºACTIVE TEST / A/F CONTROL / USER DATAº then select ºO2S
B1S1 and O2S B1S2º by pressing ºYESº button and push ºENTERº button before pressing ºF4º button.
NOTICE:
If the vehicle is short of fuel, the air-fuel ratio becomes LEAN and heated oxygen sensor DTCs will
be recorded, and the MIL then comes on.
HINT:

If different DTCs related to different systems that have terminal E2 as the ground terminal are output
simultaneously, terminal E2 may be open.

Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records
the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determin-
ing whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio
was lean or rich, etc. at the time of the malfunction.

A high heated oxygen sensor (sensor 1) voltage (0.5 V or more) could be caused by a rich air fuel mix-
ture. Check for conditions that would cause the engine to run rich.

A low heated oxygen sensor (sensor 1) voltage (0.4 V or less) could be caused by a lean air fuel mix-
ture. Check for conditions that would cause the engine to run lean.

DI-1 16
- DIAGNOSTICSENGINE
309 Author
: Date
:
2004 LAND CRUISER (RM1071U)
8 Check injector injection (See page SF-24).
NG Replace injector.
OK
Replace heated oxygen sensor.
9 Perform confirmation driving pattern.
HINT:
Clear all DTCs prior to performing the confirmation driving pattern.
Go
10 Is there DTC P0130, P0150, P2195, P2196, P2197 or P2198 being output again?
NO Check for intermittent problems
(See page DI-3).
YES
Replace ECM (See page SF-60).

- DIAGNOSTICSENGINE
DI-121
314 Author
: Date
:
2004 LAND CRUISER (RM1071U)
Front HO2S frequency monitor (cruse)
If the $90 is out of the standard value, the ECM interprets this as a malfunction.
TEST IDDescription of TEST DATAConversion FactorUnit
$90
Remained value of that average of
switching frequency is subtracted
from average of switching frequen-
cy threshold
Multiply by 0.04096 plus 5.2sec.
WIRING DIAGRAM
Refer to DTC P0031 on page DI-49.
INSPECTION PROCEDURE
HINT:
Hand-held tester only:
The narrowing down the trouble area is possible by performing ACTIVE TEST of the following ºA/F CON-
TROLº (Heated oxygen sensor or another can be distinguished).
(a) Perform ACTIVE TEST by hand-held tester (A/F CONTROL).
HINT:
ºA/F CONTROLº is the ACTIVE TEST which changes the injection volume to -12.5 % or +25 %.
(1) Connect the hand-held tester to the DLC3 on the vehicle.
(2) Turn the ignition switch ON.
(3) Warm up the engine with the engine speed at 2,500 rpm for approximately 90 seconds.
(4) Select the item ºDIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROLº.
(5) Perform ºA/F CONTROLº with the engine in an idle condition (press the right or left button).
RESULT:
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume
+25 % " rich output: More than 0.5 V
-12.5 % " lean output: Less than 0.4 V
NOTICE:
However, there is a few second delay in the sensor 1 (front sensor) output. And there is about 20 se-
conds delay in the sensor 2 (rear sensor).