oxygen sensors TOYOTA CAMRY 2000 Service Repair Manual

3
CAMRY ± NEW FEATURES49
8. Engine Control System
General
An engine control system based on the 5S-FE engine has been adopted. The knock sensor has been discon-
tinued because natural gas has a high octane value and is less susceptible to knocking.
The engine control system of 5S-FNE and 5S-FE engines are compared below.
System
Outline5S-FNE5S-FE
SFI
Se
quential
A D-type SFI system is used, which indirectly detects
intake air volume by manifold absolute pressure sensor.Sequential
Multiport Fuel
InjectionThe fuel injection system is a sequential multiport fuel
injection system.
Ignition timing is determined by the ECM based on
signals from various sensors.
ESA
Electronic Spark
AdvanceThe ECM corrects the ignition timing in response to
engine knocking in accordance with the signals
received from the knock sensor.
Ð
dva ce
Torque control correction during gear shifting had been
used to minimize the shift shock.*1
IAC
(Idle Air Control)A rotary solenoid type IAC valve controls the fast idle
and idle speeds.(1-Coil Type
Built-in Driver)(2-Coil Type)
Fuel Pump ControlFuel pump operation is controlled by signal from the
ECM.Ð
Fuel Cut-Off
Control
The fuel shutoff valves for the fuel tank, fuel pressure
regulator, and delivery pipe are shut off to stop the
supply of fuel when the ignition switch is turned OFF or
during abnormal conditions (such as engine stalling,
SRS airbag deployed, etc.).
Ð
Injector ControlPrevents the frozen stuck of the injector to ensure the
startability of the engine at low temperature.Ð
Oxygen Sensor
and Air Fuel Ratio
Sensor
Heater ControlMaintains the temperature of the oxygen sensor and air
fuel ratio sensor at an appropriate level to increase
accuracy of detection of the oxygen concentration in the
exhaust gas.
*2
EGR Cut-Off
ControlCuts off EGR according to the engine condition to
maintain drivability of the vehicle and durability of the
EGR components.

Evaporative
Emission ControlThe ECM controls the purge flow of evaporative
emissions (HC) in the charcoal canister in accordance
with engine conditions.
Ð
Air Conditioning
Cut-Off ControlBy turning the air conditioning compressor ON or OFF
in accordance with the engine condition, drivability is
maintained.
*3*3
Diagnosis
When the ECM detects a malfunction, the ECM
diagnoses and memorized the failed section.
DiagnosisThe diagnosis system includes a function that detects a
malfunction in the evaporative emission control system.Ð
Fail-Safe
When the ECM detects a malfunction, the ECM stops or
controls the engine according to the data already stored
in memory.

*1: Only for Automatic Transaxle Model
*
2: Air fuel ratio sensor only for California specification model
*
3: The air conditioning magnet clutch controled by the ECM

CAMRY ± NEW FEATURES
No.4 INJECTOR
SPARK PLUGSIGNITERS and
IGNITION COILS
No.2 INJECTOR
No.1 INJECTOR
No.3 INJECTOR
SENSORS ACTUATORS
MANIFOLD ABSOLUTE
PRESSURE SENSORSFI PIM#10+
CRANKSHAFT POSITION
SENSORNE
CAMSHAFT POSITION
SENSORG
ENGINE COOLANT TEMP.
SENSORTHW
INTAKE AIR TEMP. SENSORTHA
THROTTLE POSITION SENSORVTA
COMBINATION METER
SPD
Vehicle Speed Signal
AIR FUEL RATIO SENSOR
(Bank 1, Sensor 1)AF
HEATED OXYGEN SENSOR
(Bank 1, Sensor 2)OX2
POWER STEERING OIL
PRESSER SWITCHPSW
TAILLIGHT & REAR WINDOW
DEFOGGER SYSTEMELS
IGNITION SWITCHSTA
PARK / NEUTRAL POSITION
SWITCHNSW
STOP LIGHT SWITCHSTP
AIRBAG SENSOR ASSEMBLY
F/PS
Fuel Cut-Off Signal
#10
#20+
#20
#30+
#30
#40+
#40
ESA
IGT1,
IGT2
IGF
CONTROL VALVEIACRSD
VSV EGREGR
AIR FUEL RATIO SENSOR
HEATER AIR FUEL RATIO SENSOR
HEATER CONTROLHTAF
HEATED OXYGEN SENSOR
HEATER OXYGEN SENSOR HEATER
CONTROLHT2
MAGNET CLUTCH RERAYAIRE CONDITIONING
CUT-OFF CONTROLMGC
FUEL GAGE
LOW FUEL LEVEL WARNING
LIGHT
ECM
AIR CONDITIONING SWITCHA/C SW
R, 2, L
FUEL
FUEL W
50
Construction
The configuration of the engine control system in the 5S-FNE engine is as shown in the following chart.
(Continued)

CAMRY ± NEW FEATURES
167CN11
Intake Air
Temp. SensorSpeedometerFuel Gage & Warning
MIL
DLC3
Airbag Sensor Assembly
ECM
VSV
(for EGR)
EGR Vacuum
ModulatorIAC Valve
Throttle
Position
Sensor
Fuel Temp.
Sensor
Fuel Shutoff
ValveFuel
Pressure
Regulator
Oil
SeparatorFuel
Shutoff
Valve
Fuel
Pressure
Sensor
EGR Valve
Crankshaft Position
Sensor Manifold
Absolute
Pressure
SensorFuel Pressure
Sensor
Engine Coolant
Temp. Sensor
Camshaft
Position
Sensor
Air Fuel
Ratio Sensor
WU-TWC
Heated Oxygen Sensor
TWCManual Fuel
Shutoff
ValveFuel Filter
Fuel TankFuel Temp. Sensor
Fuel Shutoff Valve
Coupler 52
Engine Control System Diagram

11. DISCONNECT OIL PRESSURE SWITCH
CONNECTOR
12. DISCONNECT ENGINE WIRE (FOR OXYGEN
SENSORS) FROM ENGINE HANGER
13. REMOVE WATER OUTLET
(a) Disconnect the following connectors:
(1) Engine coolant temperature sender gauge con±
nector
(2) Engine coolant temperature sensor connector
(b) Disconnect the following hoses:
(1) Upper radiator hose
(2) Water bypass pipe hose
(3) Heater water hose
(4) IAC water bypass hose
(5) 2 TVV (for EVAP) vacuum hoses
14. REMOVE WATER BYPASS PIPE
(a) Disconnect the following hoses:
(1) IAC water bypass hose
(2) Heater water hose
(3) w/ Oil Cooler:
2 oil cooler water bypass hoses (5) 3 bolts and 2 nuts
(6) Exhaust manifold
(7) Gasket
(8) Retainer
(9) Cushion
(10) WU±TWC
(c) Remove the 2 bolts, water outlet and gasket.
± 5S±FE ENGINEENGINE MECHANICALEG1±44

31. ASSEMBLE EXHAUST MANIFOLD AND WARM UP
THREE±WAY CATALYTIC CONVERTER
Assemble the following parts:
(1) WU±TWC
(2) Cushion
(3) Retainer
(4) Gasket
(5) Exhaust manifold
(6) 3 bolts and 2 nuts
Torque: 29 N±m (300 kgf±cm, 22 ft±lbf)
(c) Connect the following connectors:
(1) Engine coolant temperature sender gauge con±
nector
(2) Engine coolant temperature sensor connector
29. CONNECT ENGINE WIRE (FOR OXYGEN SENSORS)
TO ENGINE HANGER
30. CONNECT OIL PRESSURE SWITCH CONNECTOR
32. INSTALL EXHAUST MANIFOLD AND WARM UP
THREE±WAY CATALYTIC CONVERTER
ASSEMBLY
(a) Install a new gasket, the exhaust manifold and WU ±
TWC assembly with the 6 nuts. Uniformly tighten the
nuts in several passes.
Torque: 49 N±m (540 kgf±cm, 36 ft±lbf)
(7) 2 converter heat insulators
(8) 8 bolts
(9) Manifold lower heat insulator
(10) 3 bolts
± 5S±FE ENGINEENGINE MECHANICALEG1±80

ELECTRONIC CONTROL SYSTEM
The CAMRY 5S±FE engine is equipped with a TOYOTA Computer Controlled System (TCCS)
which centrally controls the MFI/SFI, ESA, IAC diagnosis systems etc. by means of an Engine
Control Module (ECM±formerly MFI/SFI computer) employing a microcomputer.
The ECM controls the following functions:
1. Multiport Fuel Injection (MFI)/Sequential Multiport Fuel Injection (SFI)
The ECM receives signals from various sensors indicating changing engine operation conditions
such as:
Intake manifold pressure
Intake air temperature
Engine coolant temperature
Engine speed
Throttle valve opening angle
Exhaust oxygen content etc.
The signals are utilized by the ECM to determine the injection duration necessary for an optimum
air±fuel ratio.
2. Electronic Spark Advance (ESA)
The ECM is programmed with data for optimum ignition timing under all operating conditions.
Using data provided by sensors which monitor various engine functions (RPM, engine coolant
temperature, etc.), the microcomputer (ECM) triggers the spark at precisely the right instant.
3. Idle Air Control (IAC)
The ECM is programmed with target idling speed values to respond to different engine conditions
(engine coolant temperature, air conditioning ON/OFF, etc.). Sensors transmit signals to the ECM
which controls the flow of air through the bypass of the throttle valve and adjusts idle speed to
the target value.
4. Diagnosis
The ECM detects any malfunctions and abnormalities in the sensor network and lights a
malfunction indicator lamp in the combination meter. At the same time, trouble is identified and
a diagnostic trouble code is recorded by the EC
5. The diagnostic trouble code can be read by the
number of blinks of the malfunction indicator lamp when terminals TE1 and E1 are connected.
The diagnostic trouble codes are referred to in later page. (See page EG1±300)
Fail±Safe Function
In the event of the sensor malfunction, a back±up circuit will take over to provide minimal
driveability, and the malfunction indicator lamp will illuminate. The MFI (Multiport Fuel Injection)/SFI (Sequential Multiport Fuel Injection) system is composed
of 3 basic sub±systems: Fuel, Air Induction and Electronic Control Systems.
FUEL SYSTEM
Fuel is supplied under constant pressure to the MFI/SFI injectors by an electric fuel pump. The
injectors inject a metered quantity of fuel into the intake port in accordance with signals from the
ECM (Engine Control Module).
AIR INDUCTION SYSTEM
The air induction system provides sufficient air for engine operation.
± 5S±FE ENGINEMFI/SFI SYSTEMEG1±166

The control system consists of sensors which detect various engine conditions, and a ECM which
determines the injection volume (timing) based on the signals from the sensors.
The various sensors detect the intake air pressure, engine speed, oxygen density in the exhaust
gas, engine coolant temperature, intake air temperature and atmospheric pressure etc. and
convert the information into an electrical signal which. is sent to the ECM. Based on these signals,
the ECM calculates the optimum ignition timing for the current conditions and operates the
injectors.
The ECM not only controls the fuel injection timing, but also the self diagnostic function which
records the occurrence of a malfunction, ignition timing control, idle speed control and EGR
control.
ELECTRONIC CONTROL SYSTEM
± 5S±FE ENGINEMFI/SFI SYSTEMEG1±169

wManifold absolute pressure sensor
wThrottle position sensor Manifold absolute pressure sensor
wDefogger relay
wTaillight relay Engine coolant temp. sensorData link connector 1 and 2
Data link connector 1 and 2Malfunction indicator lamp Injectors (No.2 and No.4)
No.1 vehicle speed sensorThrottle position sensor
Throttle position sensorIntake air temp. sensorEG R gas temp. sensor
Circuit opening relay
Main oxygen sensor
Data link connector 1Sub oxygen sensor Terminal
No.Terminal
No.
A/C amplifier
EFI main relayEFI main relay Sensor ground
Sensor groundA/C amplifier
Power ground
ECM groundConnection Connection
VSV for EG R
Knock sensorSymbol Symbol
Battery Igniter
± 5S±FE ENGINETERMINALS OF ECMEG1±319

37 ENGINEÐ5S±FE ENGINE
 ENGINE CONTROL SYSTEM
1. General
The engine control system of the new 5S±FE engine is basically the same in construction and operation as that of the
previous 5S±FE engine, except fo rthe changed listed bleow.
The exhaust emissions has been reduced through the adoption of the sequential multiport fuel injection system for
engine starting and the air±fuel ratio sensor*
2
The function of an air conditioning amplifier has been internally added to the ECM.
The engine control system of the new 5S±FE engine and previous 5S±FE engine and previous 5S±FE engine are
compared below.
System
OutlineNewPrevious
SFI
(SequentialA D±type SFI system is used, which indirectly detects
intake air volume by manifold absolute pressure.(q
Multiport Fuel
Injection)The fuel injection system is a sequential multiport fuel
injection system.
ESA
(Electronic SparkIgnition Timing is determined by the ECM based on
signals from various sensors. The ECM corrects ignition
timing in response to engine knocking.

(Electronic Spark
Advance)Torque control correction during gear shifting has been
used to minimize the shift shock.*1*1
IACA rotary solenoid type IAC valve controls the fast idle(Idle Air Control)
A rotary solenoid type IAC valve controls the fast idle
and idle speeds.
Fuel Pump
ControlFuel pump operation is controlled by signal from the
ECM.
Oxygen Sensor
(Air Fuel Ratio
Sensor*
2)
Heater Control
Maintains the temperature of the oxygen sensor (or air
fuel ratio sensor*2) at an approppiate level to increase
accuracy of detection of the oxygen concentration in the
exhaust gas.Ð
EGR Cut±Off
ControlCuts off EGR according to the engine condition to
maintain drivability of the vehicle and durability of
EGR components.

Evaporative
Emission ControlThe ECM controls the purge flow of evaporative emis-
sions (HC) in the charcoal canister in accordance with
engine conditions.
*1*1
Air Conditioning
Cut±Off ControlBy turning the air conditioning compressor ON or
OFF in accordance with the engine condition,
drivability is maintained
*3
Diagnosis
When the ECM detects a malfunction, the ECM diagnoses
and memorized the failed section.
DiagnosisThe diagnosis system includes a function that detects a
malfunction in the evaporative control system.*1*1
Fail SafeWhen the ECM detects a malfunction, the ECM stops
or controls the engine according to the data already stored
in memory

*1: Only for Automatic Transaxle Models., *2: Only for California Specification Models,
*
3: The air conditioning magnet scutch controled by the ECM.

42ENGINEÐ5S±FE ENGINE
5. Main Components of Engine Control System
The following table compares the main components of the new 5S±FE engine, and previous 5S±FE engine.
Model
NewPreviousComponentNewPrevious
Manifold Absolute Pressure SensorSemiconductoru
Throttle Position SensorLinear Typeu
Crankshaft Position SensorPick±Up Coil Type, 1u
Camshaft Position SensorPick±Up Coil Type, 1Ð
DistributorCamshaft PositionPick Up Coil Type 1DistributorSensorÐPick±Up Coil Type, 1
Knock SensorBuilt±In Piezoelectric
Element Type 1u
Oxygen Sensor
Heated Oxygen Sensor
(Bank 1, Sensor 1)*
1
(Bank 1, Sensor 2)
Air Fuel Ratio Sensor*
2
Oxygen Sensor
(Bank 1, Sensor 1)
(Bank 1, Sensor 2)
Injector2±Hole Typeu
IAC ValveRotary Solenoid Typeu
*1: Except for California Specification Models.
*
2: Only for California Specification Models.
Camshaft Position Sensor
The camshaft position sensor is mounted onto the
cylinder head. Using the protusion that is provided
on the timing pulley, the sensor generates 1 signal
for every revolution. This signal is then sent to the
ECM as a cranskshaft angle system.