Toyota 2GR-FE Manual page 568

ES–412
Components
Canister
Cut-off valve
Purge VSV (Vacuum
Switching Valve)
Refueling valve
Roll-over valve
Soak timer
Canister pump
module
ES
(a) Vent valve
(b) Canister pressure
sensor
(c) Leak detection
pump
(d) Reference orifice
Canister Pump Module (fig. 1):
Vent Valve: OFF
(vent)
Canister
Reference Orifice
(0.02 Inch)
Canister Pressure
Sensor
2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
Contains activated charcoal to absorb EVAP (Evaporative Emissions) generated in fuel tank.
Located in fuel tank. Valve floats and closes when fuel tank 100 % full.
Opens or closes line between canister and intake manifold. ECM uses purge VSV to control EVAP purge flow. In order
to discharge EVAP absorbed by canister to intake manifold, ECM opens purge VSV. EVAP discharge volume to intake
manifold controlled by purge VSV duty cycle ratio (current-carrying time) (Open: ON; Closed: OFF).
Controls EVAP pressure from fuel tank to canister. Valve consists of diaphragm, spring and restrictor (diameter: 0.08
inch). When fuel vapor and pressure inside fuel tank increase, valve opens. While EVAP purged, valve closes and
restrictor prevents large amount of vacuum from affecting pressure in fuel tank. Valve opened while refueling.
Located in fuel tank. Valve closed by its own weight when vehicle overturns to prevent fuel from spilling out.
Built into ECM. To ensure accurate EVAP monitor, measures 5 hours (+-15 min) after ignition switch turned off. This
allows fuel to cool down, stabilizing EVAP pressure. When approximately 5 hours elapsed, ECM in activated (refer to
fig. 3).
Consists of (a) to (d) below. Canister pump module cannot be disassembled.
Vents and closes EVAP system. When ECM turns valve ON, EVAP system closed. When ECM turns valve off, EVAP
system vented. Negative pressure (vacuum) created in EVAP system to check for EVAP leaks by closing purge VSV,
turning on vent valve (closed) and operating leak detection pump (refer to fig. 1).
Indicates pressure as voltages. ECM supplies regulated 5 V to canister pressure sensor, and uses feedback from
sensor to monitor EVAP system pressure (refer to fig. 2).
Creates negative pressure (vacuum) in EVAP system for leak check.
Has opening with 0.02 inch diameter. Vacuum produced through orifice by closing purge VSV, turning off vent valve
and operating leak detection pump, to monitor reference pressure. Reference pressure indicates small leak of EVAP.
Condition: Purge Flow
Leak Detection
Pump: OFF
Operations
: Airflow
To Canister
Filter
(Atmosphere)
From Refueling
Valve
Vent Valve: ON
(closed)
Condition: Leak Check
Leak Detection
Pump: ON
A115902E02