2001 TOYOTA SEQUOIA fuel pressure

DI±258
± DIAGNOSTICSENGINE
452 Author: Date:
2005 SEQUOIA (RM1146U)
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 to 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 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 35C (95F) 5 hours after the ignition switch is turned off,
the monitor check starts 2 hours later. If it is still not below 35C (95F) 7 hours after the ignition switch is
turned off, the monitor check starts 2.5 hours later.
SequenceOperationsDescriptionsDuration
±ECM activationActivated by soak timer, 5 hours (7 or 9.5 hours) after ignition switch turned to OFF.±
AAtmospheric 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-
mentIn order to determine 0.02 inch leak pressure standard, vacuum pump creates negative pres-
sure (vacuum) through 0.02 inch orifice and then ECM checks if vacuum pump and vent
valve operate normally.
60 seconds
CEVAP 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*
DPurge VSV monitorPurge VSV opened and then EVAP system pressure measured by ECM.
Large increase indicates normal.10 seconds
E
Second 0.02 inch leak
pressure measure-
mentLeak 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
FFinal checkAtmospheric 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.

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, E: 0.02 Inch Leak Pressure Measurement
Negative
Pressure Atmospheric
Pressure Air Filter
Purge VSV: OFFOFF (vent)
ON
OFF
OFF
ON
ON (closed)ON
ON
ON (closed)
Operation C: EVAP System Pressure Measurement
A23483
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
Leak Pressure
sec NegativeONON
Sequence
TimeA
10
sec60
Within 15 minutes
sec ON
First 0.02 inch
BCD
OK Malfunction
ON: Open
OFF: Closed
OFF: Vent ON: Closed
10
Standard
sec60
E EVAP Pressure when Purge VSV Stuck Open:
Leak PressureSecond 0.02 inch
Standard x 0.2
± DIAGNOSTICSENGINE
DI±259
453 Author: Date:
2005 SEQUOIA (RM1146U)
(a) Purge VSV stuck open
In operation C, the vacuum pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission)
system. The EVAP system pressure is then measured by the ECM using the pressure sensor. If the stabilized
system pressure is higher than [second 0.02 inch leak pressure standard 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).

± 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±

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

± 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

B17399
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: OFFOFF (vent)
ON
OFF
OFF
ON
ON (closed)ON
ON
ON (closed)
DI±274
± DIAGNOSTICSENGINE
468 Author: Date:
2005 SEQUOIA (RM1146U)
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 35C (95F) 5 hours after the ignition switch is turned off,
the monitor check starts 2 hours later. If it is still not below 35C (95F) 7 hours after the ignition switch is
turned off, the monitor check starts 2.5 hours later.
SequenceOperationsDescriptionsDuration
±ECM activationActivated by soak timer, 5 hours (7 or 9.5 hours) after ignition switch turned to OFF.±
AAtmospheric 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-
mentIn 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
CEVAP 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*
DPurge VSV monitorPurge VSV opened and then EVAP system pressure measured by ECM.
Large increase indicates normal.10 seconds
E
Second 0.02 inch leak
pressure measure-
mentLeak 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
FFinal checkAtmospheric 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.

A23486
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
Leak Pressure
sec NegativeONON
Sequence
TimeA
10
sec60
Within 15 minutes
sec ON
First 0.02 inch
BCD
P0455
ON: Open
OFF: Closed
OFF: Vent ON: Closed
10
Standard
sec60
E
P0456
OK
EVAP Pressure when EVAP system Leaks:
Leak PressureSecond 0.02 inch
Standard x 0.2
± DIAGNOSTICSENGINE
DI±275
469 Author: Date:
2005 SEQUOIA (RM1146U)
(a) P0455: EVAP (Evaporative Emission) gross leak
In operation C, the vacuum pump creates negative pressure (vacuum) in the EVAP system and the EVAP
system pressure is measured. If the stabilized system pressure is higher than [second 0.02 inch leak pres-
sure standard x 0.2] (near atmospheric pressure), the ECM determines that the EVAP system has a large
leakage, illuminates the MIL and sets the DTC (2 trip detection logic).
(b) P0456: EVAP very small leak
In operation C, the vacuum pump creates negative pressure (vacuum) in the EVAP system and the EVAP
system pressure is measured. If the stabilized system pressure is higher than second 0.02 inch leak pres-
sure standard, the ECM determines that the EVAP system has a small leakage, illuminates the MIL and sets
the DTC (2 trip detection logic).
MONITOR STRATEGY
RltdDTCP0455Gross leak detectedRelated DTCsP0456Very small leak (0.020 inch hole) detected
Required sensors/componentsPurge VSV, Pump module
Frequency of operationOnce per driving cycles
DurationWithin 15 min. (varies with amount of fuel in tank)
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Following values are when atmospheric is
760 mmHg (100 kPa)±
EVAP key±off monitor runs when all of the
following conditions met:±

A16555
AIR INJ CHECK
AIR PUMP............................ON
EASV ............................OPEN
ASV1. .............................OPEN
ASV2...............................OPEN
A/F BANK1......................19.05
A/F BANK2........................14.5
PRESSURE....................17 kPa
PULSATION..............25.39 kPa
AI STATUS...........................OK
Remaining Time 05 sec.
Press [EXIT] to quit
± DIAGNOSTICSENGINE
DI±325
519 Author: Date:
2005 SEQUOIA (RM1146U)
7 Check air switching valve No.2 operation.
PREPARATION:
(a) Start the engine and warm it up.
(b) Turn the ignition switch to OFF.
(c) Connect the hand±held tester to the DLC3.
(d) Start the engine and push the hand±held tester main
switch ON.
CHECK:
(a) Select the following menu items: DIAGNOSIS/EN-
HANCED OBD II/SYSTEM CHECK/ AIR INJ CHECK/
MANUAL OPERATION/OPERATION 5 and 6
HINT:
OPERATION 5: AP:ON, EASV:OPEN, ASV1:OPEN,
ASV2:CLOSE
OPERATION 6: AP:ON, EASV:OPEN, ASV1:CLOSE,
ASV2:OPEN
NOTICE:
This test only allows technicians to operate the AI system
for 5 seconds. Furthermore, the test can be performed 4
times a trip. If the test is repeated, intervals of at least 30
seconds are required between tests.
While the AI system operation using the hand±held tester
is prohibited, the tester displays the prohibition (WAIT or
ERROR). If the ERROR (AI STATUS NG) is displayed on the
tester, stop the engine for 10 minutes and then try again..
(b) Read value of the A/F BANK1 and BANK2 on the hand±
held tester.
RESULT:
Air switching valve No.2 operationAir±fuel ratio
Open18 or more
CloseApproximately 14.5
HINT:

When the ASV No.2 operates normally, the A/F value is 18 or more when the valve is open, and approx-
imately 14.5 when the valve is closed.

Perform the following procedures only on the bank of which the valve is not close.
NEXT