Evap (Evaporative Emission) Control System - Toyota 2006 PRIUS Manual

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3. EVAP (Evaporative Emission) Control System

General
The EVAP (evaporative emission) control system prevents the vapor gas that is created in the fuel tank from
being released directly into the atmosphere.
The canister stores the vapor gas that has been created in the fuel tank.
The ECM controls the purge VSV in accordance with the driving conditions in order to direct the vapor
gas into the engine, where it is burned.
In this system, the ECM checks the evaporative emission leak and outputs DTCs (Diagnostic Trouble
Codes) in the event of a malfunction. An EVAP (evaporative emission) leak check consists of an
application of a vacuum pressure to the system and monitoring the changes in the system pressure in order
to detect a leakage.
This system consists of a purge VSV, VSV (for purge flow switching valve), canister, canister pump
module, fuel tank pressure sensor, and ECM.
The ORVR (Onboard Refueling Vapor Recovery) function is provided.
The canister pressure sensor has been included in the canister pump module.
The canister filter has been provided on the fresh air line. This canister filter is maintenance-free.
The fuel tank pressure sensor detects the pressure in the fuel tank while the engine is running, and sends
the resulting signal to the ECM. Based on this signal, the ECM detects any malfunction in the purge VSV
and the VSV (for purge flow switching valve).
The following are the typical conditions for enabling an EVAP leak check:
Typical Enabling Typical Enabling
Condition
Service Tip
The canister pump module performs the EVAP leak check. This check is done approximately five
hours after engine is turned off.*
So you may hear sound coming from underneath the luggage compartment for several minutes. It
does not indicate a malfunction.
*: If engine coolant temperature does not drop below 35_C (95_F), this time should be extended to 7 hours.
Even after that, if the temperature is not less than 35_C (95_F), the time should be extended to 9.5 hours.
The EVAP service port provided on the '05 models is removed from the '06 models.
NOTICE
The pinpoint pressure test procedure is carried out by pressurizing the fresh air line that runs from
the canister pump module to the fuel filler neck.
For details, refer to the 2006 Prius Repair Manual (Pub. No. RM01R0U).
NEW FEATURES - 1NZ-FXE ENGINE
Five hours have elapsed after the engine has been turned OFF. Five hours have elapsed after the engine has been turned OFF.*
Altitude: Below 2400 m (8000 feet) Altitude: Below 2400 m (8000 feet)
Battery Voltage: 10.5 V or more Battery Voltage: 10.5 V or more
Power Source Mode: OFF
Engine Coolant Temperature: 4.4 to 35_C (35 to 95_F) g p
Intake Air Temperature: 4.4 to 35_C (35 to 95_F)
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