
ENGINE - 2AZ-FXE ENGINE
02HEG35Y
Vent Valve (Vent / Close)
Leak Detection Pump (ON / OFF)
Purge VSV (Open / Close)
Fuel Vapor-containment Valve
(Open / Close)
Fuel Tank Pressure Sensor
Atmospheric Pressure (0 kPa)
Canister Pressure Sensor
at Leak Detection Pump
1
2
3
4
5
6
7
8
EG-66
Fuel Tank Internal Pressure Equals Atmospheric Pressure
Order
Operation
Description
Time
1
Atmospheric Pressure
THS ECU turns vent valve OFF (vent) and measures EVAP
10 sec
1
Atmospheric Pressure
Measurement
THS ECU turns vent valve OFF (vent) and measures EVAP
control system pressure to memorize atmospheric pressure.
10 sec.
2
0.02 in. Leak Pressure
Leak detection pump creates negative pressure (vacuum)
through 0 02 in orifice and pressure is measured THS ECU
60 sec
2
0.02 in. Leak Pressure
Measurement
through 0.02 in. orifice and pressure is measured. THS ECU
determines this as 0.02 in. leak pressure.
60 sec.
3
Canister Leak Check
Leak detection pump creates negative pressure (vacuum) in
canister leak check and canister leak check pressure is
measured. If stabilized pressure is larger than 0.02 in. leak
Within
3
Canister Leak Check
measured. If stabilized pressure is larger than 0.02 in. leak
pressure, THS ECU determines EVAP control system has leak.
If leak detection pump pressure does not stabilize within 15
minutes, THS ECU cancels EVAP monitor.
Within
15 min.
Purge VSV Monitor
Purge VSV Monitor
and Fuel
THS ECU opens purge VSV and measures EVAP control
4
and Fuel
Vapor-containment
THS ECU opens purge VSV and measures EVAP control
system pressure increase. If increase is large, THS ECU
10 sec.
4
Vapor containment
Valve Stuck Closed
system pressure increase. If increase is large, THS ECU
interprets this as normal.
10 sec.
Judgment
p
0 02 in Leak Pressure
Leak detection pump creates negative pressure (vacuum)
through 0 02 in orifice and pressure is measured THS ECU
60 sec
5
0.02 in. Leak Pressure
Measurement and
Format
through 0.02 in. orifice and pressure is measured. THS ECU
determines this as 0.02 in. leak pressure.
THS ECU t
t
l
OFF (
t)
d
i t
60 sec.
and
10 sec
Format
THS ECU turns vent valve OFF (vent) and measures canister
leak check pressure to memorize atmospheric pressure.
10 sec.
Fuel
V
t i
t
6
Vapor-containment
Valve Stuck Closed
Leak detection pump creates a negative pressure (vacuum) in
the fuel tank and the THS ECU measures the pressure at the
Approx.
6
Valve Stuck Closed
Judgment and Fuel
Tank Leakage
the fuel tank and the THS ECU measures the pressure at the
time the fuel vapor-containment valve is opened.
Approx.
15 min.
Tank Leakage
Judgment
time the fuel vapor containment valve is opened.
7
0.02 in. Leak Pressure
Leak detection pump creates negative pressure (vacuum)
through 0 02 in orifice and pressure is measured THS ECU
60 sec
7
0.02 in. Leak Pressure
Measurement
through 0.02 in. orifice and pressure is measured. THS ECU
determines this as 0.02 in. leak pressure.
60 sec.
8
Final Check
THS ECU measures atmospheric pressure and records monitor
result.
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