Toyota Sequoia (2005). Manual - part 155

–

DIAGNOSTICS

ENGINE

DI–415

609

4. Vacuum introduction and leak

–

Next sequence is run if both of following

conditions set

Condition 1 and 2

1. Vacuum introduction time

–

15 min.

2. FTP

FTP was saturated

5. Purge VSV stuck closed check

–

Next sequence is run if following condition

set

–

FTP change for 10 sec. after purge VSV

ON (open)

2.25 mmHg (0.3 kPa)

–

6. Second reference pressure measure-

ment

–

Next sequence is run if all of following

conditions set

Condition 1, 2, 3 and 4

1. FTP when 4 sec. after reference pres-

sure measurement

–

–7.5 mmHg (–1 kPa)

2. Reference pressure

–36.38 to –7.93 mmHg (–4.85 to –1.057 kPa)

3. Reference pressure

Saturated

4. Reference pressure difference between

first and second

–

5.25 mmHg (0.7 kPa)

7. Leak check

–

Next sequence is run if following condition

set

–

FTP when vacuum introduction was com-

plete

–

Second reference pressure

8. Atmospheric pressure

–

Monitor is complete if following

–

Atmospheric pressure difference between

sequence 1 and 8

–

2.25 mmHg (0.3 kPa)

TYPICAL MALFUNCTION THRESHOLDS

Detection Criteria

Threshold

Following values are when atmospheric pressure is 760

mmHg (100 kPa)

–

One of the following conditions set

Condition 1, 2, 3, 4 or 5

1. FTP when 4 sec. after reference pressure measurement

began

–7.5 mmHg (–1 kPa) or more

2. Reference pressure

–36.38 mmHg (–4.85 kPa) or less

3. Reference pressure

–7.93 mmHg (–1.057 kPa) or more

4. Reference pressure

Not saturated

5. Reference pressure difference between first and second

More than 5.25 mmHg (0.7 kPa)

MONITOR RESULT (MODE 06 DATA)

Refer to page 

DI–26

 for detailed information on Monitor Result.

INSPECTION PROCEDURE

Refer to the EVAP Inspection Procedure (see page 

DI–460

).

DI–416

–

DIAGNOSTICS

ENGINE

610

DTC

P2419

Evaporate Emission System Switching
Valve Control Circuit Low

DTC

P2420

Evaporate Emission System Switching
Valve Control Circuit High

DTC SUMMARY

DTCs

Monitoring Items

Malfunction Detection Conditions

Trouble Areas

Detection

Timings

Detection

Logic

P2419

Vent valve stuck closed

Vacuum pump creates negative pressure
through 0.02 inch orifice and EVAP system
pressure measured to determine leak pres-
sure standard. 
If system pressure higher than –1.06 kPa
(–7.95 mmHg)* 4 seconds after vacuum
pump turned ON, ECM determines that
vent valve stuck closed.

Pump module

Connector/Wire harness
(Pump module – ECM)

ECM

While 
ignition
switch
OFF

2 trip

P2420

Vent valve stuck open (vent)

Vacuum pump creates negative pressure
through 0.02 inch orifice and EVAP system
pressure measured to determine leak pres-
sure standard. 0.02 inch leak pressure
standard is measured at the start and at the
end of the leak check.
If system pressure does not increase by
more than 0.3 kPa (2.25 mmHg) within 10
seconds when vent valve turned ON, ECM
determines that vent valve stuck close.

Pump module

Connector/Wire harness
(Pump module – ECM)

ECM

While 
ignition
switch
OFF

2 trip

*: The threshold value varies according to the atmospheric pressure measured in operation A. The value
described above is based on an atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.
HINT:
The vent valve is built into the pump module.

CIRCUIT DESCRIPTION

The circuit description can be found in the EVAP (Evaporative Emission) Inspection Procedure (see page

DI–460

).

DIDFW–01

A23480

Fuel Tank

Canister

Vacuum Pump: OFF

Pressure Sensor

0.02 Inch Orifice

Pump Module

Operation A: Atmospheric Pressure Measurement

Vent Valve: OFF (vent)

Operation D: Purge VSV monitor

Operation B: 0.02 Inch Leak Pressure Measurement

Negative
Pressure

Atmospheric
Pressure

Operation C: EVAP Leak Check

Air Filter

Purge VSV: OFF

OFF (vent)

ON

OFF

OFF

ON

ON (closed)

ON

ON

ON (closed)

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DIAGNOSTICS

ENGINE

DI–417

611

MONITOR DESCRIPTION

5 hours* after the ignition switch is turned OFF, the electric vacuum pump creates negative pressure (vacu-
um) in the EVAP (Evaporative Emission) 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.

Sequence

Operations

Descriptions

Duration

–

ECM activation

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

–

A

Atmospheric pressure
measurement

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

10 seconds

B

First 0.02 inch leak
pressure measure-
ment

In order to determine 0.02 inch leak pressure standard, vacuum pump creates negative pres-
sure (vacuum) through 0.02 inch orifice and them ECM checks if vacuum pump and vent
valve operate normally.

60 seconds

C

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

15 minutes*

D

Purge VSV monitor

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

10 seconds

E

Second 0.02 inch leak
pressure measure-
ment

Leak check is performed after second 0.02 inch leak pressure standard is measured.
If stabilized system pressure higher than second 0.02 inch leak pressure standard, ECM
determines that EVAP system leaking.

60 seconds

F

Final check

Atmospheric pressure measured and then monitoring result recorded by ECM.

–

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

A23665

Purge VSV

Vent Valve

Vacuum Pump

EVAP Pressure

Positive

Leak Pressure

sec

Negative

ON

ON

Sequence

Time

A

10

sec

60

Within 15 minutes

sec

ON

First 0.02 inch

B

C

D

EVAP Pressure when Vent Valve Stuck ON (closed):

OK

Malfunction

ON: Open

OFF: Closed

OFF: Vent

ON: Closed

10

Standard

sec

60

E

sec

4

DI–418

–

DIAGNOSTICS

ENGINE

612

(a)

P2419: Vent valve stuck closed

In operation B, the vacuum pump creates negative pressure (a vacuum) through the 0.02 inch orifice. The
EVAP (Evaporative Emission) system pressure is then measured by the ECM, using the pressure sensor,
to determine the 0.02 inch leak pressure standard. If the pressure exceeds –1.06 kPa (–7.95 mmHg)* 4 se-
conds after the vacuum pump is turned ON, the ECM interprets this as the vent valve being stuck closed.
The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
*: The threshold varies according to the atmospheric pressure measured in operation A. The value described
above is based on an atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.