2000 TOYOTA CAMRY O2 sensor

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NEW FEATURES Ð 5S-FNE ENGINE13
FUEL SYSTEM
1. General
The compressed gas [maximum pressure approximately 250 kg/cm2 (3600 psi, 24.8 MPa) @215C (705F)]
from the CNG fuel tank located in the rear section of the vehicle is routed via a fuel filter to the engine
compartment. The pressure of the fuel is then reduced to 8 kg/cm
2 (114 psi, 785 kPa).
A pressure regulator and injectors designed exclusively for CNG application have been adopted.
A fuel pressure sensor and a fuel temperature sensor that are used for the correction of the fuel injection
volume are located on the delivery pipe.
The fuel tank, pressure regulator, and the delivery pipe are provided with shutoff valves that shut off
the fuel when the ignition switch is turned OFF.
In addition, these valves shut off the fuel when the engine stalls, the SRS airbag is deployed, or the
pressure in the main pipe becomes abnormally low.
A fuel temperature sensor for the fuel gauge is mounted on the tank valve assembly, and a fuel pressure
sensor is mounted immediately upstream of the pressure regulator.

Fuel System Diagram 
167CN12
Discharge
Valve
Fuel
Pressure
SensorFuel Temp.
SensorFuel
Pressure
RegulatorFuel Shutoff ValveFuel TankFuel Shutoff Valve
Relief Valve
Inlet Check
Valve
Fuel Temp.
Sensor
Coupler
Tank Valve Assembly
Vent Tube Manual
Shutoff
Valve Fuel
Filter
Fuel
Pressure
Sensor
Fuel Shutoff Valve Injectors
Delivery Pipe

NEW FEATURES Ð 5S-FNE ENGINE 14
2. Fuel Tank
A fuel tank made with carbon fiber and alumi-
num lining has been adopted to prevent weight
increase.
Because the fuel tank expands along with the
increase in the pressure of the compressed gas,
the tank bands contain coil springs to accommo-
date the fluctuation in the perimeter of the tank.
The fuel tank is provided with a tank valve as-
sembly.
3. Tank Valve Assembly
General
The tank valve assembly is mounted on the tank
and consists of a fuel shutoff valve, inlet check
valve, relief valve and two manual cutoff valves.
167CN08
Coil Springs
Tank Valve
AssemblyTank Band
167CN26
Fuel
Temperatur
Sensor
Tank Valve Assembly

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NEW FEATURES Ð 5S-FNE ENGINE17
8. Delivery Pipe
A delivery pipe with a wide passage that enables a large volume of gas to flow responsively has been
adopted to minimize the pressure loss.
A fuel pressure sensor and a fuel temperature sensor that help correct the fuel injection volume are mounted
on the delivery pipe.
Similar to the fuel shutoff valves for the fuel tank and the fuel pressure regulator, a fuel shutoff valve
is provided on the fuel inlet side of the delivery pipe to shut off the supply of fuel when the engine
is stopped or during abnormal conditions.
To discharge the fuel out of the delivery pipe during service, a discharge valve is provided.
Injector
167CN13
Discharge
ValveFuel Pressure Sensor
Fuel Temp. Sensor
Delivery Pipe
CNG
Fuel Shutoff
Valve
9. Injector
For the injection of fuel in the gaseous state, injectors that allow the flow of a large volume of fuel and
provide improved sealing performance have been adopted.
These injectors are actuated by the voltage (150V) that has been increased by the voltage booster circuit
provided in the ECM.
ECM
167CN14
167CN23
Rubber Sheet
12V
+B
Voltage
Booster
Circuit#10+
#10Injector

NEW FEATURES Ð 5S-FNE ENGINE 18
10. Fuel Temperatur and Pressure Sensor for Fuel Gage
A fuel temperature sensor that detects the temperature in the fuel tank is provided on the tank valve assembly.
A fuel pressure sensor that detects the pressure in the fuel main pipe is provided immediately upstream
of the fuel pressure regulator.
The pressure and the temperature of the fuel are detected by these sensors and are input into the ECM.
These values are then converted by the ECM into the equivalent pressure at 215C to actuate the fuel gauge.
IGNITION SYSTEM
Because the spark plugs are susceptible to rust when used with natural gas, corrosion-resistant spark plugs
have been adopted. These spark plugs are the iridium-tipped spark plugs that have their metallic portion
plated.

Recommended Spark Plug 
DENSO
SK20R11-G
Plug Gap1.0 ± 1.1 mm (0.0394 ± 0.043 in.)
167CN15
: Plating Area
Iridium Tip
Platinum Tip 0.7 mm

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NEW FEATURES Ð 5S-FNE ENGINE19
ENGINE CONTROL SYSTEM
1. General
An engine control system based on the 5S-FE engine has been adopted. The knock sensor has been discontin-
ued 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
Sequential
A D-type SFI system is used, which indirectly detects
intake air volume by manifold absolute pressure sensor.
Sequential
Multiport Fuel
Injection
The fuel injection system is a sequential multiport fuel
injection system.
Ignition timing is determined by the ECM based on sig-
nals from various sensors.
ESA
Electronic Spark
AdvanceThe ECM corrects the ignition timing in response to en-
gine knocking in accordance with the signals received
from the knock sensor.
Ð
Advance
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 sup-
ply of fuel when the ignition switch is turned OFF or
during abnormal conditions (such as engine stalling,
SRS airbag deployed, etc.).
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 accu-
racy of detection of the oxygen concentration in the ex-
haust 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 emis-
sions (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
When the ECM detects a malfunction, the ECM diag-
noses and memorized the failed section.
DiagnosisThe diagnosis system includes a function that detects a
malfunction in the evaporative emission control sys-
tem.
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

NEW FEATURES Ð 5S-FNE ENGINE
(Continued)
PIM
NE
G
THW
THA
VTA
AF
#10+
#20
#30
#40
IGT1,
IGT2
IGF
RSD
EGR
OX2
HTAF
HT2
MGC
FUEL W
PSW
ELS
NSW
F/PS
A/C SW
ECM
STA
SPD
R,2,L
STP
#40+ #30+ #20+ #10
FUEL
20
2. Construction
The configuration of the engine control system in the 5S-FNE engine is as shown in the following chart.
SENSORS
MANIFOLD ABSOLUTE
PRESSURE SENSOR
CRANKSHAFT POSITION
SENSOR
CAMSHAFT POSITION
SENSOR
ENGINE COOLANT TEMP.
SENSOR
INTAKE AIR TEMP. SENSOR
THROTTLE POSITION SENSOR
IGNITION SWITCH
COMBINATION METER
wVehicle Speed Signal
AIR FUEL RATIO SENSOR
(Bank 1, Sensor 1)
HEATED OXYGEN SENSOR
(Bank 1, Sensor 2)
POWER STEERING OIL
PRESSER SWITCH
TAILLIGHT & REAR WINDOW
DEFOGGER SYSTEM
PARK/NEUTRAL POSITION
SWITCH
STOP LIGHT SWITCH
AIR CONDITIONING SWITCH
AIRBAG SENSOR ASSEMBLY
wFuel Cut-Off Signal
ACTUATORS
SFI
No. 1 INJECTOR
No. 2 INJECTOR
No. 3 INJECTOR
No. 4 INJECTOR
ESA
IGNITERS and
IGNITION COILS
SPARK PLUGS
IAC
CONTROL VALVE
EGR
VSV
AIR FUEL RATIO SENSOR
HEATER CONTROL
AIR FUEL RATIO SENSOR
HEATER
OXYGEN SENSOR HEATER
CONTROL
HEATED OXYGEN SENSOR
HEATER
AIRE CONDITIONING
CUT-OFF CONTROL
MAGNET CLUTCH RERAY
FUEL GAGE
LOW FUEL LEVEL WARNING
LIGHT

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NEW FEATURES Ð 5S-FNE ENGINE
TE1
BATT +B
BATTERYEFI MAIN RELAYFC
THCNG 1
PCNG 1VCNG 2
SIL
ECM
THCNG 2
PCNG 2VCNG 3
+B1
21
FUEL TEMP. SENSOR for
FUEL TANK
FUEL TEMP. SENSOR for
DELIVERY PIPE
FUEL PRESSURE SENSOR for
FUEL PIPE
FUEL PRESSURE SENSOR for
DELIVERY PIPE
DATA LINK CONNECTOR 1
FUEL CUT-OFF CONTROL
CIRCUIT OPENING RELAY
FUEL SHUTOFF VALVE for
FUEL TANK
FUEL SHUTOFF VALVE
for FUEL PRESSURE
REGULATOR
FUEL SHUTOFF VALVE for
DELIVERY PIPE
DATA LINK CONNECTOR 3

NEW FEATURES Ð 5S-FNE ENGINE 22
3. Engine Control System Diagram
Fuel Tank
167CN1 1
SpeedometerFuel Gage & Warning
MIL
DLC3
Airbag Sensor Assembly
ECM
Fuel Temp.
Sensor
Fuel Shutoff
ValveFuel
Pressure
Regulator
Fuel
Shutoff
Valve
Fuel
Pressure
Sensor
Camshaft
Position
Sensor
Air Fuel
Ratio Sensor
WU-TWC
Crankshaft Position
Sensor
Heated Oxygen Sensor
TWC Engine Coolant
Temp. Sensor Fuel Pressure
Sensor
Manifold
Absolute
Pressure
Sensor EGR Valve
EGR Vacuum
Modulator
VSV
(for EGR)Intake Air
Temp. Sensor
IAC Valve
Throttle
Position
Sensor
Manual Fuel
Shutoff
Valve
Fuel Filter
Fuel Temp. Sensor
Fuel Shutoff Valve
Coupler