2001 TOYOTA SEQUOIA ABS

A23664
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
Leak Pressure
sec NegativeONON
Sequence
TimeA
10
sec60
Within 15 minutesON
First 0.02 inch
BCD
OK Malfunction
ON: Open
OFF: Closed
OFF: Vent ON: Closed
10
Standard
sec60
E
sec
EVAP Pressure when Vacuum Pump Stuck OFF: DI±412
± DIAGNOSTICSENGINE
606 Author: Date:
2005 SEQUOIA (RM1146U)
(a) P2401: Vacuum pump stuck OFF
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 is higher than ±1.06 kPa (±7.95 mmHg)*,
or lower than ±4.85 kPa (±36.38 mmHg)*, the ECM interprets this as the vacuum pump being stuck OFF
(not operating). The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
*: The thresholds vary according to the atmospheric pressure measured in operation A. The values de-
scribed above are based on an atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.

A23663
Purge VSV
Vent Valve
Vacuum Pump
EVAP Pressure
Positive
Leak Pressure
sec NegativeONON
Sequence
TimeA
10
sec60
Within 15 minutesON
First 0.02 inch
BCD
OK
Malfunction
ON: Open
OFF: Closed
OFF: VentON: Closed
10
Standard
sec60
E
sec
EVAP Pressure when Vacuum Pump Stuck ON:
± DIAGNOSTICSENGINE
DI±413
607 Author: Date:
2005 SEQUOIA (RM1146U)
(b) P2402: Vacuum pump stuck ON
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 is higher than ±1.06 kPa (±7.95 mmHg)*,
or lower than ±4.85 kPa (±36.38 mmHg)*, the ECM interprets this as the vacuum pump being stuck ON (re-
maining ON all the time). The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
*: The thresholds vary according to the atmospheric pressure measured in operation A. The values de-
scribed above are based on an atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.
HINT:
The detection logic of DTCs P2401 and P2402 is the same because in both cases the 0.02 inch leak pressure
standard measured in operation B is compared to the atmospheric pressure registered in operation A. The
ECM calculates the difference between these pressures by deducting [the 0.02 inch leak pressure standard]
from [the stored atmospheric pressure], and uses this to monitor the EVAP system pressure change.
MONITOR STRATEGY
RltdDTCP2401Vacuum pump stuck OFFRelated DTCsP2402Vacuum pump stuck ON
Required sensors/componentsPump module
Frequency of operationOnce per driving cycles
DurationWithin 2 min.
MIL operation2 driving cycles
Sequence of operationNone

DI±416
± DIAGNOSTICSENGINE
610 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P2419 Evaporate Emission System Switching
Valve Control Circuit Low
DTC P2420 Evaporate Emission System Switching
Valve Control Circuit High
DTC SUMMARY
DTCsMonitoring ItemsMalfunction Detection ConditionsTrouble AreasDetection
TimingsDetection
Logic
P2419Vent 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)

ECMWhile
ignition
switch
OFF
2 trip
P2420Vent 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)

ECMWhile
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

A23665
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
EVAP Pressure when Vent Valve Stuck ON (closed):
OK Malfunction
ON: Open
OFF: Closed
OFF: Vent ON: Closed
10
Standard
sec60
E
sec4
DI±418
± DIAGNOSTICSENGINE
612 Author: Date:
2005 SEQUOIA (RM1146U)
(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.

± DIAGNOSTICSENGINE
DI±445
639 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P043E Evaporate Emission System Reference Ori-
fice Clog Up
DTC P043F Evaporate Emission System Reference Ori-
fice High Flow
DTC SUMMARY
DTCsMonitoring ItemsMalfunction Detection ConditionsTrouble AreasDetection
TimingsDetection
Logic
P043E0.02 inch orifice clogged
Vacuum pump creates negative pressure
through 0.02 inch orifice, and EVAP system
pressure is measured to determine leak
pressure standard. 0.02 inch leak pressure
standard is measured at the start and at the
end of the leak check.
If system pressure lower than ±4.85 kPa
(±36.38 mmHg)*, ECM determines that
0.02 inch orifice has clogging malfunction.

Pump module

Connector/Wire harness
(Pump module ± ECM)

ECM

Leakage from EVAP sys-
tem
While
ignition
switch is
OFF
2 trip
P043F0.02 inch orifice high±flow
Vacuum pump creates negative pressure
through 0.02 inch orifice, and EVAP system
pressure is measured to determine leak
pressure standard. 0.02 inch leak pressure
standard is measured at the start and at the
end of the leak check.
If system pressure higher than ±1.06 kPa
(±7.95 mmHg)*, ECM determines that 0.02
inch orifice has high±flow malfunction.

Pump module

Connector/Wire harness
(Pump module ± ECM)

ECM

Leakage from EVAP sys-
tem
While
ignition
switch is
OFF
2 trip
*: The threshold values vary according to the atmospheric pressure measured at EVAP monitor beginning.
The values described in the table above are based on an atmospheric pressure of 100 kPa (750.1 mmHg)
(absolute pressure).
HINT:
The 0.02 inch orifice is located inside the pump module.
CIRCUIT DESCRIPTION
The circuit description can be found in the EVAP (Evaporative Emission) Inspection Procedure (see page
DI±460).
DID8I±01

A23481
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
EVAP Pressure when 0.02 Inch Orifice Clogged:
OK
Malfunction
ON: Open
OFF: Closed
OFF: Vent ON: Closed
10
Standard
sec60
E
± DIAGNOSTICSENGINE
DI±447
641 Author: Date:
2005 SEQUOIA (RM1146U)
(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 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 0.02 Inch Orifice High±flow malfunction: DI±448
± DIAGNOSTICSENGINE
642 Author: Date:
2005 SEQUOIA (RM1146U)
(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
RltdDTCP043E0.02 inch orifice clog (built±in pump module)Related DTCsP043F0.02 inch orifice high±flow (built±in pump module)
Required sensors/componentsPump module
Frequency of operationOnce per driving cycle
DurationWithin 2 min. (varies with amount of fuel in tank)
MIL operation2 driving cycle
Sequence of operationNone

± 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.