2001 TOYOTA SEQUOIA Page 18

± DIAGNOSTICSENGINE
DI±257
451 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0441 Evaporative Emission Control System Incor-
rect Purge Flow
DTC SUMMARY
DTCsMonitoring ItemsMalfunction Detection ConditionsTrouble AreasDetection
TimingsDetection
Logic
P0441
Purge VSV (Vacuum
Switching Valve) stuck
open
Vacuum pump creates negative pressure
(vacuum) in EVAP system and EVAP sys-
tem pressure measured. 0.02 inch leak
pressure standard is measured at the start
and at the end of the leak check.
If stabilized pressure higher than [second
0.02 inch leak pressure standard x 0.2],
ECM determines that purge VSV stuck
open

Purge VSV

Connector/wire harness
(Purge VSV ± ECM)

ECM

Pump module

Leakage from EVAP system
While ignition
Switch OFF2 trip
P0441Purge VSV stuck closed
After EVAP leak check performed, purge
VSV turned ON (open), and atmospheric
air introduced into EVAP system. 0.02 inch
leak pressure standard is measured at the
start and at the end of the leak check.
If pressure does not return to near atmo-
spheric pressure, ECM determines that
purge valve stuck closed

Purge VSV

Connector/wire harness
(Purge VSV ± ECM)

ECM

Pump module

Leakage from EVAP system
While ignition
Switch OFF2 trip
P0441Purge 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 (3.75 mmHg) when vent valve
turned ON (closed)

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

Purge VSV

Connector/wire harness
(Purge VSV ± ECM)

Leakage from EVAP line
(Purge VSV ± Intake manifold)

ECM
While engine
running2 trip
CIRCUIT DESCRIPTION
The circuit description can be found in the EVAP (Evaporative Emission) Inspection Procedure (see page
DI±460).
DID88±01

± DIAGNOSTICSENGINE
DI±261
455 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
Purge VSV stuck open
Related DTCsP0441Purge VSV stuck closedRelated DTCsP0441
Purge flow
Required sensors/componentsPurge VSV, Pump module
Frequency of operationOnce per driving cycle
DurationPurge VSV stuck open and closed: Within 2 min. (varies with amount of fuel in tank)
Purge flow: Within 30 sec.
MIL operation2 driving cycle
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Purge VSV stuck open and closed:
Following values are when atmospheric is
760 mmHg (100 kPa)±
EVAP key±off monitor runs when all of the
following conditions met:±
Atmospheric pressure525 to 825 mmHg (70 to 110 kPa)
Battery voltage10.5 V±
Vehicle speed±4 km/h (2.5 mph)
Ignition switchOFF
Engine conditionNot running
Time after engine stopped5 hours
FTP sensor malfunction (P0450, P0452,
P0453)Not detected
Purge VSVNot operated by scan tool
Vent valveNot operated by scan tool
Leak detection pumpNot operated by scan tool
Both of the following conditions are met
before IG switch OFFCondition 1 and 2
1. Duration that vehicle is driven5 min.±
2. Purge flowExecuted
ECT4.4 to 35°C (40 to 95°F)
IAT4.4 to 35°C (40 to 95°F)
Example of re±start time±
First time7 hours
Second time9 hours and 30 min.
Key±off monitor sequence1 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±

± DIAGNOSTICSENGINE
DI±263
457 Author: Date:
2005 SEQUOIA (RM1146U) Battery voltage
10 V±
Purge duty cycle8 %±
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Purge VSV stuck open:
FTP when vacuum introduction was compleatHigher than reference pressure x 0.2
Purge VSV stuck closed:
FTP change for 10 sec. after purge VSV ONLess than 2.25 mmHg (0.3 kPa)
Purge flow:
Both of the following conditions are metCondition 1 or 2
1. FTP change when purge operation is startedLess than 0.75 mmHg (0.1 kPa)
2. FTP change during purge operation when vent valve is
closedLess than 3.75 mmHg (0.5 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±264
± DIAGNOSTICSENGINE
458 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0450 Evaporative Emission Control System Pres-
sure Sensor/Switch
DTC P0451 Evaporative Emission Control System Pres-
sure Sensor/Switch Range/Performance
DTC P0452 Evaporative Emission Control System Pres-
sure Sensor/Switch Low Input
DTC P0453 Evaporative Emission Control System Pres-
sure Sensor/Switch High Input
DTC SUMMARY
DTCMonitoring ItemsMalfunction Detection ConditionsTrouble AreasDetection Tim-
ingsDetection
Logic
P0450Pressure sensor voltage ab-
normal fluctuationSensor output voltage rapidly fluctuates
beyond upper and lower malfunction
thresholds for 0.5 seconds.
Pump module

Connector/Wire harness
(Pump module ± ECM)

ECM
EVAP monitor-
ing (ignition
OFF)

Ignition ON
1 trip
P0451Pressure sensor noisingSensor output voltage fluctuates fre-
quently in certain time period.

Pump module

Connector/Wire harness
(Pump module ± ECM)

ECM
EVAP monitor-
ing (ignition
OFF)

Engine running
2 trip
P0451Pressure sensor stuckSensor output voltage does vary in cer-
tain time period.

Pump module

Connector/Wire harness
(Pump module ± ECM)

ECM
EVAP monitor-
ing (ignition
OFF)
2 trip
P0452Pressure sensor voltage lowSensor output voltage is less than 0.45
V for 0.5 seconds.

Pump module

Connector/Wire harness
(Pump module ± ECM)

ECM
Ignition ON

EVAP monitor-
ing (ignition
OFF)
1 trip
P0453Pressure sensor voltage highSensor output voltage is more than 4.9
V for 0.5 seconds.

Pump module

Connector/Wire harness
(Pump module ± ECM)

ECM
Ignition ON

EVAP monitor-
ing (ignition
OFF)
1 trip
HINT:
The pressure sensor 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).
DID89±01

DI±266
± DIAGNOSTICSENGINE
460 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
P0450Evaporative emission control system pressure
sensor/switch chattering
P0451
Evaporative emission control system pressure
sensor noise
Related DTCs
P0451Evaporative emission control system pressure
sensor stuck
P0452Evaporative emission control system pressure
sensor/switch low input
P0453Evaporative emission control system pressure
sensor/switch high input
Required sensors/componentsPump module
Frequency of operationOnce per driving cycle
Duration0.5 sec.: P0450, P0452, P0453
10 sec.: P0451
MIL operationImmediate: P0450, P0452, P0453
2 driving cycles: P0451
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Pressure sensor noise:
Atmospheric pressure525 to 825 mmHg (70 to 110 kPa)
Battery voltage10.5 V±
IAT4.4 to 35°C (40 to 95°F)
FTP sensor malfunction (P0450, P0452,
P0453)Not detected
Either of the following conditions is metCondition 1 or 2
1. Time after engine stopped5 hours
2. Engine conditionRunning
Example of re±start time±
First time7 hours
Second time9 hours and 30 min.
Pressure sensor stuck:
Battery voltage10.5 V±
IAT4.4 to 35°C (40 to 95°F)
FTP sensor malfunction (P0450, P0452,
P0453)Not detected
Atmospheric pressure525 to 825 mmHg (70 to 110 kPa)
Time after engine stopped5 hours
Example of re±start time±
First time7 hours
Second time9 hours and 30 min.

DI±268
± DIAGNOSTICSENGINE
462 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
NOTICE:

When a vehicle is brought into the workshop, leave it as it is. Do not change the vehicle condi-
tion. For example, do not tighten the fuel tank cap.

Do not disassemble the pump module.

A hand±held tester is required to conduct the following diagnostic troubleshooting procedure.
1 Confirm DTC and EVAP pressure.
PREPARATION:
(a) Connect a hand±held tester to the DLC3.
(b) Turn the ignition switch to ON (do not start the engine).
(c) Turn the tester ON.
CHECK:
(a) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
(b) Read DTCs.
(c) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / VAPOR
PRESS.
(d) Read the EVAP (Evaporative Emission) pressure displayed on the tester.
RESULT:
Display (DTC Output)Test ResultsSuspected Trouble AreasProceed To
P0451'
Pressure sensorC
P0452Less than 45 kpa (430 mmHg)

Wire harness/connector (ECM ± pressure
sensor)

Pressure sensor

Short in ECM circuit
A
P0453More than 120 kPa (900 mmHg)

Wire harness/connector (ECM ± pressure
sensor)

Pressure sensor

Open in ECM circuit
B
B Go to step 4.
C Go to EVAP inspection procedure
(See page DI±460).
A

DI±272
± DIAGNOSTICSENGINE
466 Author: Date:
2005 SEQUOIA (RM1146U)
7 Replace ECM (See page SF±80).
NEXT
8 Check whether DTC output recurs.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch to ON and turn the tester ON.
(c) Wait for at least 60 seconds.
CHECK:
(a) On the tester, select the following menu items: DIAGNOSIS/ENHANCED OBD II/DTC INFO/PEND-
ING CODES.
HINT:
If no pending DTC is displayed on the tester, the repair has been successfully completed.
NEXT
Completed

± DIAGNOSTICSENGINE
DI±273
467 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0455 Evaporative Emission Control System Leak
Detected (Gross Leak)
DTC P0456 Evaporative Emission Control System Leak
Detected (Very Small Leak)
DTC SUMMARY
DTCMonitoring ItemsMalfunction Detection ConditionsTrouble AreasDetection
TimingsDetection
Logic
P0455EVAP gross leak
Vacuum pump creates negative pressure
(vacuum) in EVAP system and EVAP sys-
tem pressure measured. 0.02 inch leak
pressure standard is measured at the start
and at the end of the leak check.
If stabilized pressure higher than [second
0.02 inch leak pressure standard x 0.2],
ECM determines that EVAP system has
large leakage.
Fuel tank cap (loose)

Leakage from EVAP line
(Canister ± Fuel tank)

Leakage from EVAP line
(Purge VSV ± Canister)

Pump module

Leakage from fuel tank

Leakage from canister
While
ignition
switch
OFF
2 trip
P0456EVAP small leak
Vacuum pump creates negative pressure
(vacuum) in EVAP system and EVAP sys-
tem pressure measured. 0.02 inch leak
pressure standard is measured at the start
and at the end of the leak check.
If stabilized pressure larger than second
0.02 inch leak pressure, ECM determines
that EVAP system has small leakage.
Same above
While
ignition
switch
OFF
2 trip
CIRCUIT DESCRIPTION
The circuit description can be found in the EVAP (Evaporative Emission) Inspection Procedure (see page
DI±460).
DID8A±01