2001 TOYOTA HIGHLANDER o2 sensor

A96746
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
G36775
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
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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
(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).

G36776
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 EVAP Pressure when Purge VSV Stuck Closed:
A71563
EVAP Pressure
During Purge Flow Monitor:
VSV
EVAP
PressureOpen
1st
Monitor2nd
Monitor
ON (closed)
Purge
Valve Vent
OK
OK
Malfunction
0.1 kPa
0.5 kPa
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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
(b) Purge VSV stuck closed
In operation D, the pressure sensor measures the EVAP system pressure. The pressure measurement for
purge VSV monitor is begun when the purge VSV is turned ON (open) after the EVAP leak check. When
the measured pressure indicates an increase of 0.3 kPa (2.25 mmHg) or more, the purge VSV is functioning
normally. If the pressure does not increase, the ECM interprets this as the purge VSV being stuck closed.
The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
2. PURGE FLOW MONITOR
The purge flow monitor consists of the two step monitors. The
1st monitor is conducted every time and the 2nd monitor is acti-
vated if necessary.

The 1st monitor
While the engine is running and the purge VSV
(Vacuum Switching Valve) is ON (open), the ECM
monitors the purge flow by measuring the EVAP
pressure change. If negative pressure is not
created, the ECM begins the 2nd monitor.

The 2nd monitor
The vent valve is turned ON (closed) and the EVAP
pressure is then measured. If the variation in the
pressure is less than 0.5 kPa (3.75 mmHg), the
ECM interprets this as the purge VSV being stuck
closed, and illuminates the MIL and sets DTC
P0441 (2 trip detection logic).
Atmospheric pressure check:
In order to ensure reliable malfunction detection, the variation
between the atmospheric pressures, before and after conduc-
tion of the purge flow monitor, is measured by the ECM.

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: Date
:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
OBD II MONITOR SPECIFICATIONS (Key-off Monitor)
Monitor Strategy
Required Sensors/ComponentsPurge VSV and pump module
Frequency of OperationOnce per driving cycle
DurationWithin 15 minutes (varies with fuel in tank)
MIL Operation2 driving cycles
Sequence of OperationNone
Typical Enabling Conditions
The monitor will run whenever these DTCs are not presentSee page 05-16
EVAP key-off monitor runs when all of the following condi-
tions met-
Atmospheric pressure525 to 825 mmHg (70 to 110 kPa)
Battery voltage10.5 V or more
Vehicle speedBelow 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
OFF:Condition 1 and 2
1. Duration that vehicle is driven5 min. or more
2. Purge flowExecuted
ECT4.4 to 35C (40 to 95F)
IAT4.4 to 35C (40 to 95F)
Example of re-start time
First time7 hours
Second time9 hours and 30 min.
Key-of f monitor sequence: 1 to 8
1. Atmospheric pressure
Next sequence is run if following condition met-
Atmospheric pressure change for 10 sec.Within 2.25 mmHg (0.3 kPa) for 1 sec.
2. First reference pressure
Next sequence is run if all of following conditions metCondition 1, 2 and 3
1. FTP when 4 sec. after reference pressure measurement-7.5 mmHg (-1 kPa) or less
2. Reference pressure-36.47 to -7.93 mmHg (-4.85 to -1.057 kPa)
3. Reference pressureSaturated
3. Vent valve stuck closed check
Next sequence is run if following condition met-
FTP change for 10 sec. after vent valve ON (closed)2.25 mmHg (0.3 kPa) or more
4. Vacuum introduction and leak
Next sequence is run if both of following conditions metCondition 1 and 2
1. Vacuum introduction timeWithin 15 min.
2. FTPFTP was saturated
5. Purge VSV stuck closed check
Next sequence is run if following condition met-
FTP change for 10 sec. after purge VSV ON (open)2.25 mmHg (0.3 kPa) or more

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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
6. Second reference pressure measurement
Next sequence is run if all of following conditions metCondition 1, 2, 3 and 4
1. FTP when 4 sec. after reference pressure measurement-7.5 mmHg (-1 kPa) or less
2. Reference pressure-36.47 to -7.93 mmHg (-4.85 to -1.057 kPa)
3. Reference pressureSaturated
4. Reference pressure difference between first and secondLess than 5.25 mmHg (0.7 kPa)
7. Leak check
Next sequence is run if following condition met-
FTP when vacuum introduction was completeLower than second reference pressure
8. Atmospheric pressure
Monitor is complete if following-
Atmospheric pressure difference between sequence 1 and 8Within 2.25 mmHg (0.3 kPa)
Typical Malfunction Thresholds
Purge VSV stuck open
FTP when vacuum introduction was completeHigher than reference pressure x 0.2
Purge VSV stuck closed
FTP change for 10 seconds after purge VSV ON (open)Less than 2.25 mmHg (0.3 kPa)
OBD II MONITOR SPECIFICATIONS (Purge Flow Monitor)
Monitor Strategy
Required Sensors/ComponentsPurge VSV and pump module
Frequency of OperationOnce per driving cycle
DurationWithin 30 seconds
MIL Operation2 driving cycles
Sequence OperationNone
Typical Enabling Conditions
The monitor will run whenever these DTCs are not presentSee page 05-16
EngineRunning
ECT4.4C (40F) or more
IAT4.4C (40F) or more
FTP sensor malfunctionNot detected
Purge VSVNot operated by scan tool
EVAP system checkNot operated by scan tool
Battery voltage10 V or more
Purge duty cycle8 % or more
Typical Malfunction Thresholds
Both of the following conditions are met:Condition 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)
Refer to page 05-317 for detailed information on Monitor Result.

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DTC P0442 EVAPORATIVE EMISSION CONTROL
SYSTEM LEAK DETECTED (SMALL LEAK)
DTC P0455 EVAPORATIVE EMISSION CONTROL
SYSTEM LEAK DETECTED (GROSS LEAK)
DTC P0456 EVAPORATIVE EMISSION CONTROL
SYSTEM LEAK DETECTED (VERY SMALL
LEAK)
CIRCUIT DESCRIPTION
The circuit description can be found in the EVAP INSPECTION PROCEDURE (see page 05-679).
INSPECTION PROCEDURE
Refer to the EVAP INSPECTION PROCEDURE (see page 05-679).
MONITOR DESCRIPTION
The ECM tests the Evaporative Emissions (EVAP) system using the fuel tank pressure sensor, Canister
Close Valve (CCV), and EVAP VSV. The ECM closes the EVAP system and creates negative pressure (vacu-
um) into it. The ECM then monitors the internal pressure using the fuel tank pressure sensor (refer to the
Leak Check graphic).
P0442, P0455 and P0456
A leak in the evaporative emission system prompts the ECM to set DTC P0442, P0455 or P0456.
The ECM checks if the EVAP has leaks. First, the ECM opens the EVAP VSV while the CCV is closed. After
a sufficient amount of time has passed, a high negative pressure(vacuum) will develop in the fuel tank as
air is drawn into the intake manifold. The EVAP VSV is then closed. The ECM then monitors the pressure
increase (loss of vacuum) in the fuel tank. If the pressure rises beyond a specified amount, the ECM deter-
mines that the system has a leak, turns on the MIL and outputs a DTC.
The ECM has separate DTCs for small and large leaks:
(1) DTC P0442 is set when the internal fuel tank pressure has a large increase and the EVAP system
has a small leak.
(2) DTC P0455 is set when the EVAP system has a very large leak. The ECM tries to create negative
pressure (vacuum) in the fuel tank by opening the EVAP VSV while the CCV is closed. However,
the fuel tank pressure does not decrease beyond a specified threshold.
(3) DTC P0456 is set when the internal fuel tank pressure increases slightly and the EVAP system
has a very small leak.
05MOQ-01

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2005 HIGHLANDER REPAIR MANUAL (RM1144U)DTC No.
DTC Detection ConditionTrouble Area
P0442
P0455
P0456
Cold engine start.
EVAP VSV has been operated and turned OFF, sealing nega-
tive pressure (vacuum) in system.
ECM begins to monitor fuel tank pressure increase and one
of the following occurs (2 trip detection logic):
(a) Rapid, sharp increase in pressure occurs, indicating small
leak in EVAP system. DTC P0442 is set.
(b) Negative pressure (vacuum) is not strong enough, indicat-
ing large hole in EVAP system. DTC P0455 is set.
(c) Increase in pressure above expected amount occurs, indi-
cating small leak in EVAP system. DTC P0456 is set.
Vacuum hose has cracks, holes, or is blocked, damaged or
disconnected
Fuel tank cap incorrectly installed
Fuel tank cap has cracks or is damaged
Open or short in vapor pressure sensor circuit
Vapor pressure sensor
Open or short in EVAP VSV circuit
EVAP VSV
Open or short in CCV circuit
 CCV
Fuel tank has cracks, holes, or is damaged
Charcoal canister has cracks, holes, or is damaged
Fuel tank over fill check valve cracks, or is damaged
ECM

A76973
ECM
Fuel Tank
Charcoal
Canister EVAP VSV
Vapor Pressure
Sensor
CCV EVAP Service
PortIntake Air
Throttle
Valve
Fuel Tank Cap
Air Cleaner Case
Charcoal Canister Filter Charcoal Filter
Intake Manifold
Purge Line
Air Inlet Line EVAP Line Purge Line
Diaphragm
(Atmospheric Pressure)
Restrictor
Passage
When EVAP VSV is opened, partial vacuum is created
When CCV is
opened, air is
drawn or released
Leak Detection Area
(Purge Valve)
Air Cleaner Filter
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MONITOR STRATEGY
Related DTCs
P0442: EVAP 0.04 inch leak
P0455: EVAP gross leak
P0456: EVAP 0.02 inch leak
Required sensors / components (Main)CCV, EVAP canister, EVAP hose, Fuel cap, Fuel tank and Purge VSV
Required sensors / components (Related)ECT sensor, FTP sensor, IAT sensor, MAF meter, Vehicle speed sensor
Frequency of operationOnce per driving cycle
DurationWithin 90 seconds
MIL operation2 driving cycles
Sequence operationNone
TYPICAL ENABLING CONDITIONS
All:
The monitor will run whenever these DTCs are not presentSee page 05-377
AltitudeLess than 7,870 ft. (2,400 m)
Battery voltage11 V or more
Throttle position learningCompleted
IAT at engine start - ECT at engine start-7 to 11.1C (-12.6 to 20F)
EVAP VSV and CCVNot operated test by scan tool
Either of the following conditions is metCondition 1 or 2
1. Purge duty cycle8% or more (vary with MAF)
2. Purge concentration for 30 seconds-5 %/% or more when vehicle speed is less than 10 km/h (6.25 mph)
RefuelNot refueled with engine running
FTP12.75 mmHg (-1.7 kPa) or more
EVAP 0.02 inch leak P0456:
ECT at engine start4.4 to 32C (39.9 to 89.6F)
IAT at engine start4.4 to 32C (39.9 to 89.6F)
IAT4.4C (39.9F) or more
Vehicle speed changeVehicle is driven by steady speed
Fuel sloshNo sloshing (i.e. fairly smooth road)
Time after engine startWithin 50 minutes
FTP change before vacuum introductionMinimum change
Fuel levelLess than 90 %
0.04 inch leakNot detected
CCV malfunctionNot detected
Vehicle speedLess than 81.25 mph (130 km/h)
Purge VSV malfunctionNot detected
Others:
ECT at engine start4.4 to 35C (39.9 to 95F)
IAT at engine start4.4 to 35C (39.9 to 95F)
IAT4.4C (39.9F) or more
Vehicle speed changeVehicle is driven by steady speed
Fuel sloshNo sloshing (i.e. fairly smooth road)
Time after engine startWithin 50 minutes
FTP change before vacuum introductionMinimum change
Fuel levelLess than 90 %