Toyota Tundra. Manual — part 1572

Fig. 169: Evaporative Emission System Operation Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

The leak detection pump creates negative pressure through the reference orifice. When the system is normal, the
EVAP pressure is between 724 to 752 mmHg* and saturated within a minute. If not, the ECM interprets this as
a malfunction. The ECM will illuminate the MIL and set a DTC if this malfunction is detected in consecutive
drive cycles.

*: Typical value.

C

pressure
measurement

Write down measured value as it will be used in leak check.
If EVAP pressure does not stabilize within 15 minutes, ECM
cancels EVAP system monitor.

minutes

(1)

D

Purge VSV monitor

Purge VSV opened and then EVAP system pressure measured
by ECM.
Large increase indicates normality.

10

seconds

E

Second reference
pressure
measurement

After second reference pressure measurement, leak check
performed by comparing first and second reference pressure.
If stabilized system pressure higher than second reference
pressure, ECM determines that EVAP system leaking.

60

seconds

-

Final check

Atmospheric pressure measured and then monitoring result
recorded by ECM.

-

(1)

If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

Fig. 170: EVAP Pressure Chart - Key-Off Monitor
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

"Saturated" indicates that the EVAP pressure change is less than 0.286 kPa-g (2.14 mmHg-g) in 60 seconds.

Required Sensors/Components

Canister pump module

Frequency of Operation

Once per driving cycle

Duration

Within 2 minutes

MIL Operation

2 driving cycles

Sequence of Operation

None

Monitor runs whenever following DTCs not present

P0452, P0453 (EVAP System)

EVAP key-off monitor runs when all of following conditions met -
Atmospheric pressure

70 to 110 kPa-a (525 to 825 mmHg-a)

Battery voltage

10.5 V or more

Vehicle speed

Below 4 km/h (2.5 mph)

Ignition switch

Off

Time after key off

5 or 7 or 9.5 hours

Purge VSV

Not operated by scan tool

Vent valve

Not operated by scan tool

Leak detection pump

Not operated by scan tool

Both of following conditions met before key off

Conditions 1 and 2

1. Duration that vehicle driven

5 minutes or more

2. EVAP purge operation

Performed

ECT

4.4 to 35°C (40 to 95°F)

IAT

4.4 to 35°C (40 to 95°F)

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

TYPICAL MALFUNCTION THRESHOLDS - EVAP PRESSURE CHANGE

MONITOR RESULT

Refer to CHECKING MONITOR STATUS .

DTC P0441 EVAPORATIVE EMISSION CONTROL SYSTEM INCORRECT PURGE FLOW

DTC SUMMARY

DTC SUMMARY

One of following conditions met

-

EVAP pressure just after reference pressure measurement started More than -1 kPa-g (-7.5 mmHg-g)
Reference pressure

Less than -4.85 kPa-g (-36.4 mmHg-g)

Reference pressure

-1.057 kPa-g (-7.93 mmHg-g) or more

Reference pressure

Not saturated within 60 seconds

Reference pressure difference between first and second

0.7 kPa-g (5.25 mmHg-g) or more

DTC

Monitoring

Item

Malfunction

Detection

Condition

Trouble Area

Detection

Timing

Detection

Logic

Purge VSV
(Vacuum
Switching
Valve) stuck
open

Leak detection
pump creates
negative pressure
(vacuum) in EVAP
system and EVAP
system pressure
measured.
Reference pressure
measured at start
and at end of leak
check.
If stabilized
pressure higher
than [second
reference pressure
x 0.2], ECM
determines that
purge VSV stuck
open.



Purge VSV



Connector/wire
harness (Purge
VSV - ECM)



ECM



Canister pump
module



Leakage from
EVAP system

While ignition
switch off

2 trip

After EVAP leak
check performed,
purge VSV turned
ON (open), and
atmospheric air
introduced into
EVAP system.



Purge VSV



Connector/wire
harness (Purge
VSV - ECM)



ECM



Canister pump

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

DESCRIPTION

The description can be found in the EVAP (Evaporative Emission) System (See DESCRIPTION ).

P0441

Purge VSV
stuck closed

Reference pressure
measured at start
and at end of
check.
If pressure does
not return to near
atmospheric
pressure, ECM
determines that
purge VSV stuck
closed.

module



Leakage from
EVAP system

While ignition
switch off

2 trip

Purge flow

While engine
running, following
conditions
successively met:



Negative
pressure not
created in
EVAP
system when
purge VSV
turned ON
(open)



EVAP
system
pressure
change less
than 0.4
kPa-g (3
mmHg-g)
when vent
valve turned
ON (closed)



Atmospheric
pressure
change
before and
after purge
flow monitor
less than 0.1
kPa-g (0.75
mmHg-g)



Purge VSV



Connector/wire
harness (Purge
VSV - ECM)



Leakage from
EVAP line
(Purge VSV -
Intake
manifold)



ECM

While engine
running

2 trip

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra