2001 TOYOTA SEQUOIA fuel pressure

± DIAGNOSTICSENGINE
DI±463
657 Author: Date:
2005 SEQUOIA (RM1146U)Components
Operations
CanisterContains activated charcoal to absorb EVAP (Evaporative Emissions) generated in fuel tank.
Cut±off valveLocated in fuel tank. Valve floats and closes when fuel tank is 100 % full.
Purge VSV (Vacuum
Switching Valve)Opens or closes line between canister and intake manifold. ECM uses purge VSV to control EVAP purge flow. In order
to discharge EVAP absorbed by canister to intake manifold, ECM opens purge VSV. EVAP discharge volume to intake
manifold controlled by purge VSV duty cycle ratio (current±carrying time). (Open: ON, Close: OFF)
Refueling valve
Controls EVAP pressure from fuel tank to canister. Valve consists of diaphragm, spring and restrictor (diameter: 0.08
inch). When fuel vapor and pressure inside fuel tank increase, valve opens. While EVAP purged, valve closes and re-
strictor prevents large amount of vacuum from affecting pressure in fuel tank. Valve opened while refueling. When valve
open, adding fuel into fuel tank possible.
Roll±over valveLocated in fuel tank. Valve closes by its own weight when vehicle overturns to prevent fuel from spilling out.
Service portUsed for connecting vacuum gauge for inspecting EVAP system.
Soak timerBuilt into ECM. To ensure accurate EVAP monitor, measures 5 hours* after ignition switch turned to OFF. This allows
fuel to cool down, stabilizing Fuel Tank Pressure (FTP). When approx. 5 hours
* elapsed, ECM activates.
Pump moduleConsists of (a) to (d) below. Pump module cannot be disassembled.
(a) Vent valve
Vents and closes EVAP system. When ECM turns valve ON, EVAP system closed. When, ECM turns valve OFF, EVAP
system vented. Negative pressure (vacuum) created in EVAP system to check for EVAP leaks by closing purge VSV,
turning on vent valve (closed) and operating vacuum pump (refer to fig. 1).
(b) Pressure sensorIndicates pressure as voltages. ECM supplies regulated 5 V to pressure sensor, and uses feedback from sensor to
monitor EVAP system pressure (refer to fig 2).
(c) Vacuum pumpCreates negative pressure (vacuum) in EVAP system for leak check.
(d) 0.02 inch orificeHas opening with 0.02 inch diameter. Vacuum produced through orifice by closing purge VSV, turning off vent valve and
operating vacuum pump, to monitor 0.02 inch leak pressure. 0.02 inch leak pressure indicates small leak of EVAP.
HINT:
*:If the engine coolant temperature is not below 35C after 5 hours after the ignition switch is turned off, the
monitor check starts 2 hours later. If it is still not below 35C 7 hours after the ignition switch is turned off,
the monitor check starts 2.5 hours later.

A23494
Pump Module (fig. 1):
Condition: Purge FlowCondition: Leak Check
From Refueling Valve
To Air Filter
(Atmosphere)
Vacuum Pump: OFFVent Valve: OFF
(vent)
Pressure Sensor 0.02 Inch Orifice
Canister
: Airflow
Vacuum Pump: ON
Vent Valve: ON
(closed)
A23495
Pressure Sensor Specification (fig. 2)
Output Voltage
Usable Range
4.900 V
4.150 V
1.425 V
0.450 V
Malfunction Area
Pressure
60
kPa11 0
kPa
Malfunction Area
Standard atmospheric pressure is 101.3 kPaHINT:
A23496
Soak Timer Circuit (fig. 3)
Ignition Switch
IGSW
Power
ECM
EFI MAIN
MREL+B
15 ASource IC
Soak Timer IC Main Relay
Control IC
Battery DI±464
± DIAGNOSTICSENGINE
658 Author: Date:
2005 SEQUOIA (RM1146U)

0.02 inch orifice clogged
Pressure sensor voltage lowP043E
P043FP0441 P0451 P0452 P0453 P0455 P0456 P2419P2401
P2402
0.02 inch orifice high±flow
Pressure sensor stuck
Pressure sensor noising
Gross leak
Small leak
Vacuum pump stuck OFF
Vacuum pump stuck ON
Vent valve stuck ON (closed)
Vent valve stuck OFF (vent) Purge VSV stuck open
Purge VSV stuck closed
Pressure sensor voltage high
DTCs
Malfunctioning AreasP2420P0450
DI±466
± DIAGNOSTICSENGINE
660 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
NOTICE:
A hand±held tester is required to conduct the following diagnostic troubleshooting procedure.
HINT:

Using hand±held tester monitor results enables the EVAP (Evaporative Emission) system to be con-
firmed.

Read freeze frame data using a hand±held tester Freeze frame data record the engine condition when
malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle
was moving or stationary, if the engine was warmed up or not, if the air±fuel ratio was lean or rich, and
other data, from the time the malfunction occurred.
1 Confirm DTC.
(a) Turn the ignition switch to OFF and wait for 10 seconds.
(b) Turn the ignition switch to ON.
(c) Turn the ignition switch to OFF and wait for 10 seconds.
(d) Connect a hand±held tester to the DLC3.
(e) Turn the ignition switch to ON and turn the tester ON.
(f) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
(g) Confirm DTCs and freeze frame data.
If any EVAP system DTCs are set, the malfunctioning area can be determined using the table below.
NOTICE:
If the 0.02 inch reference pressure difference between the first and second checks is greater than
the specification, the DTCs corresponding to the reference pressure (P043E, P043F, P0441, P0455,
P0456, P2401, P2420) will be all stored.
NEXT

A23497
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
Leak PressureON: Open
NegativeONON
Steps
(Reference)60 Within 15 minutes 10 60ON
First 0.02 inch
2/5 3/5 4/55/5
OFF: Closed
OFF: Vent ON: Closed
EVAP SYSTEM CHECK
sec sec sec
Normal Pressure
10
sec
1/5
Gross Leak
No Leak Small Leak
TimeLeak Pressure
Second 0.02 inch
StandardStandard x 0.2
DI±468
± DIAGNOSTICSENGINE
662 Author: Date:
2005 SEQUOIA (RM1146U)
3 Perform EVAP system manual operation check.
NOTICE:

In the EVAP SYSTEM CHECK (MANUAL OPERATION), the series of 5 EVAP SYSTEM CHECK
steps is performed manually.

Do not perform the EVAP SYSTEM CHECK when the fuel tank is more than 90% full because
the cut±off valve may be closed and making the leak check of the fuel tank unavailable.

Do not run the engine in this step.

When the temperature of the fuel is 35C (95F) or more, a large amount of vapor forms and any
check results become inaccurate. When performing the EVAP SYSTEM CHECK, keep the tem-
perature below 35C
(95F).
(a) Clear DTCs (see page DI±43).
(b) On the hand±held tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / SYS-
TEM CHECK / EVAP SYS CHECK / MANUAL OPERATION.
NEXT

A23502
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
Leak PressureON: Open
NegativeONON
Steps
(Reference)Within 15 minutesON
First 0.02 inch
3/5
OFF: Closed
OFF: Vent ON: Closed
Time Standard
± DIAGNOSTICSENGINE
DI±473
667 Author: Date:
2005 SEQUOIA (RM1146U)
8 Perform EVAP system step 3/5 check.
(a) Wait until the EVAP pressure change is less than 0.1 kPa (0.75 mmHg) for 30 seconds.
(b) Measure the EVAP pressure and record it.
HINT:
A few minutes are required for the EVAP pressure to become saturated. When there is little fuel in the fuel
tank, it takes up to 12 minutes.
NEXT

DI±478
± DIAGNOSTICSENGINE
672 Author: Date:
2005 SEQUOIA (RM1146U)
13 Check fuel tank cap.
CHECK:
(a) Check that the fuel tank cap is correctly installed.
(b) Confirm that the fuel tank cap is tightened until a few click sounds are heard.
HINT:
If an EVAP tester is available, check the fuel tank cap using the tester.
(1) Remove the fuel tank cap and install it onto a fuel tank cap adaptor.
(2) Connect an EVAP tester pump hose to the adaptor, and pressurize to 3.2 to 3.7 kPa (24 to 28
mmHg) using an EVAP tester pump.
(3) Seal the adaptor and wait for 2 minutes.
(4) Check the pressure. If the pressure is 2 kPa (15 mmHg) or more, the fuel tank cap is normal.
(5) Reinstall the fuel tank cap.
PREPARATION:
Test ResultsSuspected Trouble AreasProceed To
Fuel tank cap correctly installed'A
Fuel tank cap loose

Fuel tank cap improperly installed

Defective fuel tank cap

Fuel tank cap does not meet OEM specifications
B
No fuel tank cap'C
A Go to step 29.
B Go to step 27.
C Go to step 28.

A23477SST
Pressure Gauge
Pressure
B06546
± DIAGNOSTICSENGINE
DI±487
681 Author: Date:
2005 SEQUOIA (RM1146U)
27 Correctly reinstall or replace fuel tank cap.
HINT:

When reinstalling the fuel tank cap, tighten it until a few click sounds are heard.

When replacing the fuel tank cap, use a fuel tank cap that meets OEM specifications, and install it until
a few click sounds are heard.
NEXT Go to step 37.
28 Replace fuel tank cap.
HINT:
When installing the fuel tank cap, tighten it until a few click sounds are heard.
NEXT Go to step 37.
29 Repair EVAP leak part.
(a) Prepare a rubber hose with a 15 to 18.5 mm inside diame-
ter.
(b) Reinstall the fuel tank cap.
(c) Disconnect the atmospheric side hose of the pump mod-
ule.
(d) Connect the rubber tube to the pump module.
(e) Using SST, pinch the rubber tube to close the canister
passage to air.
SST 00002±6872A
(f) Connect a pressure gauge (SST) to the service port
(green cap near the air cleaner box).
(g) Pressurize the EVAP system to 3.2 to 3.7 kPa (24 to 28
mmHg).
(h) Apply soapy water to the piping and connecting parts of
the EVAP system. Look for areas where bubbles appear.
This indicates leaking points.
(i) Repair or replace leaking point.
HINT:

If the system has leaks, a whistling sound will be heard.

Disconnect the hose between the canister and the fuel
tank from the canister. Close the canister hose connected
to the fuel tank, and conduct an inspection. In this way, the
fuel tank can be excluded as an area suspected of caus-
ing fuel leaks.
NEXT Go to step 36.

DI±490
± DIAGNOSTICSENGINE
684 Author: Date:
2005 SEQUOIA (RM1146U)
(b) Monitor Conditions
(1) Allow the engine to idle for at least 5 minutes.
(2) Turn the ignition switch to OFF and wait for 6 hours (8 or 10.5 hours).
HINT:
Do not start the engine until checking MONITOR STATUS. If the engine is started, the steps described above
must be repeated.
(c) Monitor Status
(1) Connect a hand±held tester to the DLC3.
(2) Turn the ignition switch to ON and turn the tester ON.
(3) On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / MONITOR
STATUS.
(4) Check the Monitor Status displayed on the tester.
HINT:
If INCMP is displayed, the monitor is not completed. Make sure that the preconditions have been met, and
perform the Monitor Conditions again.
2. PURGE FLOW MONITOR CONFIRMATION (P0441)
HINT:
Perform this monitor confirmation after the Key±Off Monitor Confirmation shows COMPL (complete).
(a) Preconditions
The monitor will not run unless:

The vehicle has been driven for 10 minutes or more (in a city area or on a free way)

The ECT is between 4.4C and 35C (40F and 95F)

The IAT is between 4.4C and 35C (40F and 95F)
(b) Monitor Conditions
(1) Release the pressure from the fuel tank by removing and reinstalling the fuel tank cap.
(2) Warm the engine up until the ECT reaches more than 75C (167F).
(3) Increase the engine speed to 3,000 rpm once.
(4) Allow the engine to idle and turn A/C ON for 1 minute.
(c) Monitor Status
(1) Turn the ignition switch to OFF (where ON or the engine is running).
(2) Connect a hand±held tester to the DLC3.
(3) Turn the ignition switch to ON and turn the tester ON.
(4) On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / MONITOR
STATUS.
(5) Check the Monitor Status displayed on the tester.
HINT:
If INCMP is displayed, the monitor is not completed. Make sure that the preconditions have been met, and
perform the Monitor Conditions again.