Toyota Sequoia (2005). Manual - part 163

A23481

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 0.02 Inch Orifice Clogged:

OK

Malfunction

ON: Open
OFF: Closed

OFF: Vent

ON: Closed

10

Standard

sec

60

E

–

DIAGNOSTICS

ENGINE

DI–447

641

(a)

P043E: 0.02 inch orifice clogged

In operation B, the vacuum pump creates negative pressure (vacuum) through the 0.02 inch orifice. The
EVAP system pressure is then measured by the ECM, using the pressure sensor, to determine the 0.02 inch
leak pressure standard. If the pressure is lower than –4.85 kPa (–36.38 mmHg)*, the ECM interprets this
as a clog malfunction in the 0.02 inch orifice, and stops the EVAP (Evaporative Emission) system monitor.
The ECM then 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.

A23482

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

OK

Malfunction

ON: Open

OFF: Closed

OFF: Vent

ON: Closed

10

Standard

sec

60

E

EVAP Pressure when 0.02 Inch Orifice High–flow malfunction:

DI–448

–

DIAGNOSTICS

ENGINE

642

(b)

P043F: 0.02 inch orifice high–flow

In operation B, the vacuum pump creates negative pressure (vacuum) through the 0.02 inch orifice. The
EVAP system pressure is then measured by the ECM using the pressure sensor to determine the 0.02 inch
leak pressure standard. If the pressure is higher than –1.06 kPa (–7.95 mmHg)*, the ECM interprets this as
a high–flow malfunction in the 0.02 inch orifice, and stops the EVAP system monitor. The ECM then illumi-
nates 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 a atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.

MONITOR STRATEGY

R l t d DTC

P043E

0.02 inch orifice clog (built–in pump module)

Related DTCs

P043F

0.02 inch orifice high–flow (built–in pump module)

Required sensors/components

Pump module

Frequency of operation

Once per driving cycle

Duration

Within 2 min. (varies with amount of fuel in tank)

MIL operation

2 driving cycle

Sequence of operation

None

–

DIAGNOSTICS

ENGINE

DI–449

643

TYPICAL ENABLING CONDITIONS

It

Specification

Item

Minimum

Maximum

The monitor will run whenever these

DTCs are not present

See page 

DI–18

Following values are values when atmo-

spheric is 760 mmHg (100 kPa)

–

EVAP key–off monitor runs when all of the

following conditions met:

–

Atmospheric pressure

525 to 825 mmHg (70 to 110 kPa)

Battery voltage

10.5 V

–

Vehicle speed

–

4 km/h (2.5 mph)

Ignition switch

OFF

Engine condition

Not running

Time after engine stopped

5 hours

FTP sensor malfunction (P0450, P0452,

P0453)

Not detected

Purge VSV

Not operated by scan tool

Vent valve

Not operated by scan tool

Leak detection pump

Not operated by scan tool

Both of the following conditions are met

before IG switch OFF

Condition 1 and 2

1. Duration that vehicle is driven

5 min.

–

2. Purge flow

Executed

ECT

4.4 to 35

°

C (40 to 95

°

F)

IAT

4.4 to 35

°

C (40 to 95

°

F)

Example of re–start time

–

First time

7 hours

Second time

9 hours and 30 min.

Key–off monitor sequence

1 to 8

1. Atmospheric pressure

–

Next sequence is run if following condition

set

–

Atmospheric pressure change for 10 sec.

–

2.25 mmHg (0.3 kPa) for 1 sec.

2. First reference pressure

–

Next sequence is run if all of following

conditions set

Condition 1, 2 and 3

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

3. Vent valve stuck closed check

–

Next sequence is run if following condition

set

–

FTP change for 10 sec. after vent valve

ON (closed)

2.25 mmHg (0.3 kPa)

–

4. Vacuum introduction and leak

–

DI–450

–

DIAGNOSTICS

ENGINE

644

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 is met

–

FTP when 4 sec. after reference pressure measurement

began

More than –7.5 mmHg (–1 kPa)

Reference pressure

Less than –36.38 mmHg (–4.85 kPa)

Reference pressure

–7.93 mmHg (–1.057 kPa) or more

Reference pressure

Not saturated

Reference pressure difference between first and second

5.3 mmHg (0.7 kPa) or more

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

).