ENGINE AND EMISSION CONTROL SYSTEM 6E1-31
HEATED OXYGEN SENSOR (HO2S-1 AND HO2S-2)
OXYGEN SENSOR HEATER INSPECTION
1) Disconnect sensor connector.
2) Using ohmmeter, measure resistance between terminals
“V
B” and “GND” of sensor connector.
If found faulty, replace oxygen sensor.
Resistance of oxygen sensor heater
HO2S-1 : 5.0 – 6.4
Ω at 20°C (68°F)
HO2S-2 : 11.7 – 14.3
Ω at 20°C (68°F)
3) Connect sensor connector securely.
REMOVAL
1) Disconnect negative cable at battery.
2) For HO2S-1, disconnect connector of heated oxygen sensor
and release its wire harness from clamps, then remove front
bumper and heat insulator panel.
3) For HO2S-2, disconnect connector of heated oxygen sensor
and release its wire harness from clamp and hoist vehicle.
4) Remove heated oxygen sensor (1) from exhaust manifold or
exhaust pipe.
INSTALLATION
Reverse removal procedure noting the following.
Tighten heated oxygen sensor (1) to specified torque.
Tightening torque
Heated oxygen sensor (a) : 45 N·m (4.5 kg-m, 32.5 lb-ft)
Connect connector of heated oxygen sensor (1) and clamp
wire harness securely.
After installing heated oxygen sensor (1), start engine and
check that no exhaust gas leakage exists. NOTE:
Temperature of sensor affects resistance value largely.
Make sure that sensor heater is at correct temperature.
1. Viewed from terminal side
WARNING:
To avoid danger of being burned, do not touch exhaust
system when system is hot. Oxygen sensor removal
should be performed when system is cool.
[A] : HO2S-1
[B] : HO2S-2
6E1-34 ENGINE AND EMISSION CONTROL SYSTEM
FUEL CUT OPERATION
INSPECTION
1) Warm up engine to normal operating temperature.
2) While listening to sound of injector (1) by using sound scope
(2) or such, increase engine speed to higher than 3,000 r/
min.
3) Check to make sure that sound to indicate operation of injec-
tor stops when throttle valve is closed instantly and it is
heard again when engine speed is reduced to less than
about 2,000 r/min.
RADIATOR FAN CONTROL SYSTEM
SYSTEM INSPECTION
Check system for operation referring to Flow Table B-7 in Section
6.
If radiator fan fails to operate properly, check relay, radiator fan
and electrical circuit.
RADIATOR FAN RELAY NO. 2 AND NO.3
INSPECTION
1) Disconnect negative cable at battery.
2) Remove relay(s) from connector(s).NOTE:
Before inspection, check to make sure that gear shift
lever is in neutral position (with A/T model, selector lever
in “P” range), A/C is OFF and that parking brake lever is
pulled all the way up.
WARNING:
Keep hands, tools, and clothing away from engine cool-
ing fan to help prevent personal injury. This fan is electric
and can come on whether or not the engine is running.
The fan can start automatically in response to the ECT
sensor with the ignition switch in the “ON” position.
1. Radiator fan relay No. 2
2. Radiator fan relay No. 3
1
2
6E1-38 ENGINE AND EMISSION CONTROL SYSTEM
3) Connect purge hose to EVAP canister and warm up engine
to normal operating temperature.
4) Disconnect purge hose from EVAP canister.
5) Also check that vacuum is felt when engine is running at idle
speed.
If check result is not satisfactory, check vacuum passage,
hoses, EVAP canister purge valve, wire harness and ECM.
VACUUM PASSAGE INSPECTION
Start engine and run it at idle speed. Disconnect vacuum hose (1)
from EVAP canister purge valve (2). With finger placed against
hose disconnected, check that vacuum is applied.
If it is not applied, clean vacuum passage by blowing compressed
air.
VACUUM HOSE INSPECTION
Check hoses for connection, leakage, clog and deterioration.
Replace as necessary.
EVAP CANISTER PURGE VALVE INSPECTION
Check EVAP canister purge valve referring to step 1 of DTC
P0443 Flow Table.
If found malfunction, replace.NOTE:
The EVAP canister purge system does not perform purg-
ing (vacuum is not detected at the purge hose) unless the
engine is sufficiently warmed up and the heated oxygen
sensor is activated fully. Also, when the purge hose is
disconnected in Step 4), the air is drawn into the purge
line. As a result, ECM detects a change in the purge gas
concentration and sometimes stops purging but this
indicates nothing abnormal.
6H-2 CHARGING SYSTEM
GENERAL DESCRIPTION
BATTERY
The battery has three major functions in the electrical system.
It is a source of electrical energy for cranking the engine.
It acts as a voltage stabilizer for the electrical system.
It can, for a limited time, provide energy when the electrical load exceeds the output of the generator.
CARRIER AND HOLD-DOWN
The battery carrier should be in good condition so that it will support the battery securely and keep it level.
Before installing the battery, the battery carrier and hold-down clamp should be clean and free from corrosion
and make certain there are no parts in carrier.
To prevent the battery from shaking in its carrier, the hold-down bolts should be tight enough but not over-tight-
ened.
ELECTROLYTE FREEZING
The freezing point of electrolyte depends on its specific gravity. Since freezing may ruin a battery, it should be
protected against freezing by keeping it in a fully charged condition. If a battery is frozen accidentally, it should
not be charged until it is warmed.
SULFATION
If the battery is allowed to stand for a long period in discharged condition, the lead sulfate becomes converted
into a hard, crystalline substance, which will not easily turn back to the active material again during the subse-
quent recharging. “Sulfation” means the result as well as the process of that reaction. Such a battery can be
revived by very slow charging and may be restored to usable condition but its capacity is lower than before.
BUILT-IN INDICATOR (IF EQUIPPED)
The battery has a built-in temperature compensated indicator in the top of the battery. This indicator is to be
used with the following diagnostic procedure. When checking the indicator, make sure that the battery has a
clean top. A light may be needed in some poorly-lit areas.
Three types of indication available under normal operation are as
follows.
Green Dot
Battery is sufficiently charged for testing.
Dark
Battery must be charged before testing.
If there is a cranking complaint, battery should be tested as
described in Diagnosis section. Charging and electrical sys-
tems should also be checked at this time.
Clear or Light Yellow
This means that fluid level is below the bottom of hydrome-
ter. Its possible cause is excessive or prolonged charging, a
broken case, excessive tipping or normal battery deteriora-
tion. When the battery is found in such condition, it is possi-
ble that high charging voltage is caused by the faulty
charging system and therefore, charging and electrical sys-
tems need to be checked. If there is a trouble in cranking
and its cause lies in the battery, it should be replaced.
CHARGING SYSTEM 6H-3
CARE OF BATTERY
1) The battery is a very reliable component, but needs periodical attentions.
Keep the battery carrier clean
Prevent rust formation on the terminal posts
Keep the electrolyte up to the upper level uniformly in all cells.
When keeping battery on vehicle over a long period of time, follow instructions given below.
–Weekly, start the engine and run it until it reaches normal operating temperature with engine speed of
2000 to 3000 rpm. Make sure all electric switches are off before storing the vehicle.
–Recharge the battery twice a month to prevent it from discharging excessively. This is especially impor-
tant when ambient temperature is low.
The battery discharges even when it is not used, while vehicles are being stored. Battery electrolyte can
freeze and battery case can crack at cold ambient condition if battery is not properly charged.
2) Keep the battery cable connections clean.
The cable connections, particularly at the positive (+) terminal post, tend to become corroded. The product
of corrosion, or rust, on the mating faces of conductors resists the flow of current.
Clean the terminals and fittings periodically to ensure good metal-to-metal contact, and grease the connec-
tions after each cleaning to protect them against rusting.
3) Be always in the know as to the state of charge of the battery. The simplest way to tell the state of charge is
to carry out a hydrometer test. The hydrometer is an instrument for measuring the specific gravity (S.G.) of
the battery electrolyte. The S.G. of the electrolyte is indicative of the state of charge. Refer to “DIAGNOSIS”
of BATTERY in this section. WARNING:
Never expose battery to open flame or electric spark because of battery generate gas which is flam-
mable and explosive.
Do not allow battery fluid to contact eyes, skin, fabrics, or painted surfaces as fluid is a corrosive
acid. Flush any contacted area with water immediately and thoroughly.
Batteries should always be kept out of reach of children.
CHARGING SYSTEM 6H-5
DIAGNOSIS
BATTERY
VISUAL INSPECTION
Check for obvious damage, such as cracked or broken case or cover, that could permit loss of electrolyte. If
obvious damage is noted, replace battery. Determine cause of damage and correct as needed.
HYDROMETER TEST
The direct method of checking the battery for state of charge is to
carry out a high rate discharge test, which involves a special pre-
cise voltmeter and an expensive instrument used in the service
shops, but not recommendable to the user of the vehicle.
At 20 °C of battery temperature (electrolyte temperature):
The battery is in FULLY CHARGED STATE if the electrolyte
S.G. is 1.280.
The battery is in HALF CHARGED STATE if the S.G. is
1.220.
The battery is in NEARLY DISCHARGED STATE if the S.G.
is 1.150 and is in danger of freezing.
As the S.G. varies with the temperature, if battery temperature is
not at 20°C (68°F), you have to correct your S.G. reading (taken
with your hydrometer) to the value at 20°C (68°F) and apply the
corrected S.G. value to the three-point guide stated value.
For the manner of correction, refer to the graph showing the rela-
tion between S.G. value and temperature at the left.
How to use the temperature-corrected state-of-charge graph
Suppose your S.G. reading is 1.28 and the battery temperature is
–5°C (23°F). Locate the intersection of the –5°C line and the 1.28
S.G. line.
The intersection is within the “A” zone (shaded area in the graph)
and that means CHARGED STATE.
To know how much the battery is charged, draw a line parallel to
the zone demarcation line and extend it to the right till it meets
with the percentage scale. In the present example, the line meets
at about 85% point on the percentage scale. Therefore, the bat-
tery is charged up to the 85% level.
CHARGING SYSTEM 6H-7
UNDERCHARGED BATTERY
This condition, as evidenced by slow cranking or indicator clear
with red dot can be caused by one or more of the following condi-
tions even though indicator lamp may be operating normal.
Following procedure also applies to cars with voltmeter and
ammeter.
Make sure that undercharged condition has not been caused
by accessories left on for extended period of time.
Check drive belt for proper tension.
If battery defect is suspected, refer to BATTERY section.
Inspect wiring for defects. Check all connections for tight-
ness and cleanliness, battery cable connections at battery,
starting motor and ignition ground cable.
NO-LOAD CHECK
1) Connect voltmeter and ammeter as shown in left figure.
2) Run engine from idling up to 2,000 rpm with all accessories
turned off and read meters.
If voltage is higher than standard value, check ground of
brushes.
If brushes are not grounded, replace IC regulator.
If voltage is lower than standard value, proceed to following
check.
Specification for undercharged battery (No-load check)
Current: 10 A
Voltage: 14.2 – 14.8 V (at 25°C, 77°F) NOTE:
Use fully charged battery.
1. Generator
2. Ammeter (between generator (B) terminal and battery (+) terminal)
3. Voltmeter (between generator (B) terminal and ground)
4. Battery
5. Load
6. Switch
NOTE:
Consideration should be taken that voltage will differ
somewhat with regulator case temperature as shown in
left figure.
A: Regulated voltage (V)
B: Heatsink temperature (°C)
16.0
15.5
14.2 15.3
14.8
14.2
13.314.8
15.0
14.5
14.0
13.5
13.0
-30 0 25 135
[A]
[B]
6H-8 CHARGING SYSTEM
3) Ground F terminal and start engine, then measure voltage at
B terminal as shown in left figure.
Voltage is higher than standard value
It is considered that generator itself is good but IC regulator
has been damaged, replace IC regulator.
Voltage is lower than standard value
Generator itself has problem, check the generator.
LOAD CHECK
1) Run engine at 2,000 rpm and turn on head light and heater
motor.
2) Measure current and if it is less than 20 A repair or replace
generator.
OVERCHARGED BATTERY
1) To determine battery condition, refer to Battery section.
2) If obvious overcharge condition exists as evidenced by
excessive spewing of electrolyte, measure generator B ter-
minal voltage at engine 2000 rpm.
3) If measured voltage is higher than upper limit value, disas-
semble generator.
4) Check ground of brushes. If brushes are not grounded,
replace IC regulator. Then check field coil for grounds and
shorts.
A: Regulated voltage (V)
B: Heatsink temperature (°C)
16.0
15.5
14.2 15.3
14.8
14.2
13.314.8
15.0
14.5
14.0
13.5
13.0
-30 0 25 135
[A]
[B]