Toyota Tundra. Manual — part 1209

TYPICAL MALFUNCTION THRESHOLDS

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

TYPICAL MALFUNCTION THRESHOLDS

MONITOR RESULT

Refer to CHECKING MONITOR STATUS .

DTC P0441 EVAPORATIVE EMISSION CONTROL SYSTEM INCORRECT PURGE FLOW

DTC SUMMARY

DTC SUMMARY CHART

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)

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

Purge VSV

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



Purge VSV



Connector/wire
harness (Purge
VSV - ECM)

While
ignition

2 trip

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

DESCRIPTION

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

INSPECTION PROCEDURE

Refer to the EVAP SYSTEM .

MONITOR DESCRIPTION

The two monitors, Key-Off and Purge Flow, are used to detect malfunctions relating to DTC P0441. The Key-
Off monitor is initiated by the ECM internal timer, known as the soak timer, 5 hours* after the ignition switch is
turned OFF. The purge flow monitor runs while the engine is running.

1. KEY-OFF MONITOR

5 hours* after the ignition switch is turned OFF, the leak detection pump creates negative pressure
(vacuum) in the EVAP system. The ECM monitors for leaks and actuator malfunctions based on the
EVAP pressure.

HINT:

*: If the engine coolant temperature is not below 35°C (95°F) 5 hours after the ignition switch is turned
OFF, the monitor check starts 2 hours later. If it is still not below 35°C (95°F) 7 hours after the ignition
switch is turned OFF, the monitor check starts 2.5 hours later.

P0441

stuck closed

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



ECM Canister
pump module



Leakage from
EVAP system

switch
OFF

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 0.5 kPa-g
(3.75 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

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

MONITOR DESCRIPTION CHART

Sequence

Operation

Description

Duration

-

ECM activation

Activated by soak timer 5, 7 or 9.5 hours after ignition switch
turned OFF.

-

A

Atmospheric
pressure
measurement

Vent valve turned OFF (vent) and EVAP system pressure
measured by ECM in order to register atmospheric pressure.
If pressure in EVAP system not between 70 kPa-a and 110
kPa-a (525 mmHg-a and 825 mmHg-a), ECM cancels EVAP
system monitor.

10

seconds

B

First reference
pressure
measurement

In order to determine reference pressure, leak detection pump
creates negative pressure (vacuum) through reference orifice
and then ECM checks if leak detection pump and vent valve
operate normally.

60

seconds

C

EVAP system
pressure
measurement

Vent valve turned ON (closed) to shut EVAP system.
Negative pressure (vacuum) created in EVAP system, and
EVAP system pressure then measured.
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.

15

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.

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

Fig. 151: Monitor Description - EVAP System Pressure Measurement

a. Purge VSV stuck open

In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP system.
The EVAP system pressure is then measured by the ECM using the canister pressure sensor. If the
stabilized system pressure is higher than [second reference pressure x 0.2], the ECM interprets this
as the purge VSV (Vacuum Switching Valve) being stuck open. The ECM illuminates the MIL and
sets the DTC (2 trip detection logic).

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra