Lexus ES300 (2002 year). Manual — part 131
ENGINE – 1MZ-FE ENGINE
EG-47
189EG31
ORVR (On-Board Refueling
Vapor Recovery) Valve
Vapor
Pressure
Sensor
Vacuum
Check
Valve
Tank Valve
Assembly
Tank Pressure
Valve
Charcoal Canister
Pressure
Switching
Valve
Air Inlet Valve
Air Valve
Assembly
Air Drain
Valve
VSV
(for Pressure
Switching Valve)
VSV
(for Canister
Closed Valve)
Purge Line
Flesh Air Line
Service
Port
Canister
Closed
Valve
From Air
Cleaner
VSV
(for EVAP)
To Intake
Manifold
Purge
Valve
12. Evaporative Emission Control System
General
The vacuum type has been adopted on the ’02 ES300 to detect leaks in the evaporative emission control
system. This vacuum type detects leaks by forcefully introducing the purge vacuum into the entire system
and monitoring the changes in the pressure. It consists of the following main components:
A VSV (for canister closed valve) that closes the fresh air line from the air cleaner to the charcoal canister
has been adopted.
A VSV (for pressure switching valve) that opens the evaporator line between the fuel tank and the char-
coal canister has been adopted.
Function to close the purge line from the air intake chamber to the charcoal canister for this system is
added to the original functions of VSV (for EVAP).
A vapor pressure sensor that measures the pressure in the fuel tank while checking for evaporative emis-
sion leaks and sends signals to the ECM has been adopted.
ENGINE – 1MZ-FE ENGINE
EG-48
208EG32
To Intake
Manifold
From Air
Cleaner
Open
Open
Close
Close
Open
Close
208EG33
Open
Close
Close
Close
Open
To
Atmosphere
Close
Operation
1) Purge Flow
When the engine has reached predetermined parameters (closed loop, engine coolant temp. above 74
C
(165
F), etc.), stored fuel vapors are purged from the charcoal canister whenever the purge valve is
opened by the ECM. At the appropriate time, the ECM will turn on the VSV (for EVAP).
The ECM will change the duty ratio cycle of the VSV (for EVAP) thus controlling purge flow volume.
Purge flow volume is determined by manifold pressure and the duty ratio cycle of the VSV (for EVAP).
Atmospheric pressure is allowed into the canister to ensure that purge flow is constantly maintained
whenever purge vacuum is applied to the canister.
2) ORVR (On-Board Refueling Vapor Recovery)
During refueling, low pressure above the diaphragm in the onboard recovery valve lifts allowing fuel
vapors into the charcoal canister. At the same time, the air drain valve opens and the charcoal absorbs
the fuel vapors.
ENGINE – 1MZ-FE ENGINE
EG-49
208EG34
189EG33
Open
From Air
Cleaner
To Intake
Manifold
Open
Close
Close
Open
Close
Canister
Closed Valve
Pressure
Switching Valve
Purge Valve
Open
Close
Open
Close
Open
Close
Cold Start
Engine Coolant / Intake Air
Near Same Temp.
Negative
Pressure
Occurs
Fuel Tank &
Charcoal
Canister Leak
Check
VSV (for Canister
Closed Valve), VSV
(for Pressure Switching
Valve) Testing
Abnormal
Vapor Pressure
Normal
Vapor Pressure
3) Monitor
The monitor sequence begins with a cold engine start. The intake air temp. and engine coolant temp. sen-
sors must have approximately the same temperature reading. The ECM is constantly monitoring fuel tank
pressure. As the temperature of the fuel increases, pressure slowly rises. The ECM will purge the charcoal
canister at the appropriate time. With VSV (for pressure switching valve) closed, pressure will continue
to rise in fuel tank.
ENGINE – 1MZ-FE ENGINE
EG-50
189EG34
Close
Close
Close
Open
Close
Close
189EG35
To Intake
Manifold
Open
Close
Close
Open
Close
Close
4) DTC P0440, P0442 (Evaporative Emission Control System Malfunction)
Initially, when the canister closed valve is closed, and the pressure switching valve and the purge valve are
opened, a vacuum is applied to the purge line from the air intake to the charcoal canister and to the evapora-
tor line from the charcoal canister to the fuel tank. Next, the purge valve is closed in order to maintain a
vacuum from the VSV (for EVAP) to the inside of the fuel tank. Then, any subsequent changes in the pres-
sure are monitored by the vapor pressure sensor in order to check for evaporative emission leaks.
If a leak is detected, the MIL (Malfunction Indicator Lamp) illuminates to inform the driver. Also, the
DTC (Diagnostic Trouble Code) can be accessed through the use of a hand-held tester.
For details on the DTCs, refer to the 2002 ES300 Repair Manual (Pub. No. RM911U).
5) DTC P0441 (Evaporative Emission Control System Incorrect Purge Flow)
At a predetermined point, the ECM closed the canister closed valve and opens the pressure switching
valve causing a pressure drop in the entire EVAP system. The ECM continues to operate the VSV (for
EVAP) until the pressure is lowered to a specified point at which time the ECM closed the purge valve.
If the pressure did not drop, or if the drop in pressure increase beyond the specified limit, the ECM judges
the VSV (for EVAP) and related components to be faulty and the MIL illuminates to inform the driver.
Also, the DTC can be accessed through the use of a hand-held tester.
For details on the DTCs, refer to the 2002 ES300 Repair Manual (Pub. No. RM911U).
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