2000 TOYOTA CAMRY pressure switch

READINESS MONITOR DRIVE PATTERNS ± EG003-02 RevisedMarch 29, 2002
Page 17 of 23
Drive Pattern Preconditions
The monitor will not run unless:

MIL is OFF.

Fuel level is between 1/2 to 3/4 full (for faster completion)
.

Altitude is 7800 feet (2400 m) or less.*

ECT (Coolant Temp) is between 40F and 95F (4.4C ± 35C).

IAT (Intake Air) is between 40F and 95F (4.4C ± 35C).*

Cold Soak Procedure has been completed.
* For 2002 MY and later vehicles: The readiness test can be completed in cold ambient conditions
(less than 40F / 4.4C) and/or at high altitudes (more than 7800 feet / 2400 m) if the complete drive
pattern (including Cold Soak) is repeated a second time after cycling the ignition OFF.
NOTE:
Before starting the engine, the difference between ECT (Coolant Temp) and IAT (Intake
Air) must be less than 13F (7C). (Refer to Examples 1 and 2 on previous page.)
Drive Pattern Procedure

Connect the OBDII Scantool to DLC3 to check monitor status and preconditions.

Release the pressure in the fuel tank by removing and then reinstalling the fuel tank
cap.
2a. Start the engine and allow it to idle until ECT (Coolant Temp) is 167F (75C) or
greater. (See illustration on previous page.)
2b. Race the engine at 3,000 rpm for approximately 10 seconds. (See illustration on
previous page.)
2c. Allow the engine to idle with the A/C ON (to create a slight load) for 15 ± 50
minutes. (See illustration on previous page.)
NOTE:
If the vehicle is not equipped with A/C put a slight load on the engine by doing the
following:

Securely set the parking brake.

Block the drive wheels with wheel chocks.

Allow the vehicle to idle in drive for 15 ± 50 minutes.
NOTE:
The readiness status may not switch to ªcompleteº after the first drive pattern trip if a
Pending Code has been set (first trip for a two±trip DTC).

Pending Codes are available from the DTC Info Menu in Enhanced OBDII.

Pending Codes indicate a POTENTIAL problem was detected. A second trip is
needed to confirm the DTC prior to diagnosis.

Once a second trip is completed, a current DTC will be stored. Readiness
Monitor
Drive
Patterns:
EVAP
Monitors
(Continued)

EVAP SYSTEM OPERATION INFORMATION ± EG005-01 April 27, 2001
Page 3 of 14
ORVR Operation
During refueling, low pressure above the
diaphragm in the onboard recovery valve
lifts allowing fuel vapors into the charcoal
canister. At the same time, the air drain
valve opens and the charcoal absorbs the
fuel vapors (see Figure 2).
Early Type (Non±Intrusive) EVAP System DTCs
EVAP Monitor Leak Operation P0440
The ECM tests for leaks by measuring
EVAP system pressure in the lines,
charcoal canister, and fuel tank. When
the EVAP pressure is higher or lower than
atmospheric pressure, the ECM
concludes that no leaks are present.
EVAP pressure is measured by the vapor
pressure sensor. If either the tank or
canister purge side is at atmospheric
pressure under specific conditions, the
ECM determines there is a leak.
If DTC P0440 is present, the leak is on
the fuel tank side of the EVAP system.
This also includes the lines between the
fuel tank and part of the canister. When
the Vapor Pressure sensor is measuring
tank pressure, the ECM is observing
changes in pressure and comparing tank
pressure to atmospheric pressure. No
difference in pressure indicates a leak.
The ECM may take 20 minutes or more to
complete testing the fuel tank side (see
Figure 3).
Canister Leak Detection P0446
When the ECM switches the vapor
pressure VSV to canister side, the ECM
measures canister pressure. A leak on
the canister side can set multiple DTCs
(see Figure 4).Early Type
System
Description
(Continued)
Figure 2. ORVR Operation
Figure 3. Fuel Tank Side of System
Figure 4. Canister Side of System

EVAP SYSTEM OPERATION INFORMATION ± EG005-01 April 27, 2001
Page 4 of 14
Vapor Purge Flow P0441
The EVAP monitor is designed to detect:
Restricted vapor purge flow when the
purge VSV is open
Inappropriate vapor purge flow when
the purge VSV is closed
Under normal purge conditions, pressure
pulsations generated by the cycling of the
purge VSV are present in the canister
and detected by the Vapor Pressure
sensor.
Three±Way VSV P0446
The three±way VSV is connected to the Vapor Pressure sensor, canister, and fuel tank.
This VSV allows the Vapor Pressure sensor to detect either canister or tank pressure.
There are two modes the ECM can use to determine if the three±way VSV is
malfunctioning. The three±way VSV is judged to be normal if there is pressure difference
between the tank and canister when the three±way VSV is switched to look at the
charcoal canister and fuel tank side of system.
If there isn't any pressure difference between the fuel tank and canister, the ECM looks
for the following conditions:
During purging, pressure pulsations generated by the purge VSV are not present in
the canister as detected by Vapor Pressure sensor, the three±way VSV is judged to
be defective.
If there are pressure pulsations detected by the Vapor Pressure sensor present in the
fuel tank, the three±way VSV is judged to be defective.
Late Type (Intrusive) EVAP System Overview
The Late Type EVAP System, also known as the Intrusive type, was developed to meet
the very stringent, mandated standard of detecting a hole 0.020 inch (0.5 mm). This
system uses many of the same components as the early type EVAP system. Purge,
vacuum relief, pressure relief, and ORVR operations are identical to the early type. Refer
to the Applicable Vehicles chart for applicability information.
The following changes were made to the Late Type EVAP System:
Vapor pressure sensor connected to the fuel tank.
Bypass VSV in the place of the three way VSV.
Canister Closed Valve (CCV) on the air inlet line.Early Type
System
Description
(Continued)
Figure 5. Flow During Purge Operation
Late Type
System
Description

EVAP SYSTEM OPERATION INFORMATION ± EG005-01 April 27, 2001
Page 11 of 14
Diagnostic Process Flow Chart
(Continued on following page)
PRELIMINARY CHECK
Fuel level should be between
1/4 and 3/4
Visually inspect for presence
of Fuel/Gas Cap
DO NOT TIGHTEN OR REMOVE!
PRESSURIZE EVAP SYSTEM (System Integrity Check)
This test checks for leaks in the canister and fuel tank sides. The CCV and Air Inlet Lines will be checked
separately.
A) Clamp the air drain hose on the charcoal canister with the supplied hose pliers from the EVAP System
Pressure Test Kit.
B) Locate the vapor pressure sensor. If the vapor pressure sensor has two hoses connected to it,
disconnect the hose between the air drain hose fitting at the vapor pressure sensor and plug the hose.
C) Connect the pressure supply hose from the Pressure Test Kit to the Green EVAP System Service Port
located on the EVAP Purge VSV line in the engine compartment.
D) Using the directions on the inside of the EVAP System Pressure Test Kit lid, pressurize the EVAP
system. Once pressurized, turn off the pump and seal the system (Pressure Hold Switch to ªClosedº
and Vent Switch to ªClosed).
E) After 30 seconds, note the pump pressure gauge reading and the Scan Tool vapor pressure
sensor reading.
F) Compare the readings to one of the four conditions listed below and proceed as directed.
DO NOT PROCEED! NG
OK
SCAN TOOL SETUP
A) Connect Scan Tool to DLC3 on vehicle.
B) Go to the SETUP menu and select UNIT CONVERSION.
C) Under VAPOR PRESSURE, Select ABS for absolute pressure, and mmHg for millimeters of mercury.
This is to match the Repair Manual specifications.
D) Go back to FUNCTION SELECT menu and select ENHANCED OBD II.
E) Select NORMAL MODE. Then select CURRENT DATA and USER SELECT.
F) Using the arrow key, select VAPOR PRESS from the DATA LIST and select YES.
G) Press ENTER. You will now be able to monitor the Vapor Pressure Sensor reading.
START
If vehicle is ECHO, go directly to ªECHO Canister and Tank Leak Checkº on page 14.
If vehicle is not ECHO, follow the flow chart below.
Diagnostic
Tips for Late
Type EVAP
System
(Continued)

EVAP SYSTEM OPERATION INFORMATION ± EG005-01 April 27, 2001
Page 12 of 14
Pump pressure
gauge and vapor
pressure above
atmospheric
pressure (above 762
mmHg). No leak in
canister or tank.Pump pressure
gauge zero, vapor
pressure above
atmospheric
pressure (above 762
mmHg). Leak is on
canister side of
system.Pump pressure
gauge is above
atmospheric
pressure (above
zero), vapor
pressure is at
762 mmHg. Leak is
on the fuel tank side
of system.Pump pressure
gauge at zero,
vapor pressure is
at 762 mmHg. The
leak(s) is/are on the
canister and tank
sides or a leak at a
point common to
both sides of system.
Remove hose pliers
from the air drain
hose on the charcoal
canister before
proceeding with
additional checks.Remove hose pliers
from the air drain
hose on the charcoal
canister before
proceeding with
additional checks.Remove hose pliers
from the air drain
hose on the charcoal
canister before
proceeding with
additional checks.
Go to CCV/Air Inlet
Line Check.Go to ªCanister Leak
Check.º Diagram on
page 13.Go to ªFuel Tank
Leak Check.º
Diagram on page 13.Go to ªFuel Tank
Leak Check.º
Diagram on page 13.
Remove hose pliers
from the air drain
hose on the charcoal
canister before
proceeding with
additional checks.
Go to ªReturn Vehicle to Serviceº on page 14.
CCV and Air Inlet Line Check. (Except ECHO)
A) Disconnect the air inlet line from the charcoal canister.
B) Using the supplied step±down brass adapter (or equivalent) connect the Pressure Supply Hose to
the air inlet line.
C) Using the Scan Tool Active Test, turn on the CCV. This will close the CCV.
D) Pressurize the line. Once pressurized, turn off the pump and seal the line (Pressure Hold Switch to
ªClosedº and Vent Switch to ªClosedº). Pressure should hold. If not, check CCV and connections.
E) Next, using the Scan Tool, turn off the CCV. This will open the CCV. The pressure should decrease.
If not, check the CCV and connections.
F) After completing the test, reconnect air inlet line to charcoal canister. Diagnostic Process Flow Chart (Continued)
(Continued from previous page)
Diagnostic
Tips for Late
Type EVAP
System
(Continued)

EVAP SYSTEM OPERATION INFORMATION ± EG005-01 April 27, 2001
Page 13 of 14
Disconnect
EVAP Hose Here
A. Using the supplied brass step±down adapter, disconnect the EVAP hose from
the charcoal canister side as indicated above. Connect Pressure Supply hose
from Pressure Test Kit to the EVAP hose and pressurize the fuel tank to
30 mmHg (4 kPa / 0.58 psi).
B. Check that the internal pressure of the tank will hold for 1 minute. Check shaded
areas for leaks (soapy water can be used for leak detection). If pressure holds, then
perform the Canister Leak Check.
C. When done, reconnect the EVAP line hose to the charcoal canister. Fuel Tank Leak Check (Except ECHO)
Canister Leak Check (Except ECHO)
A. Connect the Pressure Supply hose from the Pressure Test Kit to the Green EVAP
System Service Port located on the EVAP Purge VSV line in the engine compartment.
B. Using the directions on the inside of the EVAP System Pressure Test Kit lid,
pressurize the EVAP system. Once pressurized, turn off the pump and seal the system
(Pressure Hold Switch to ªClosedº and Vent Switch to ªClosedº)
C. With system pressurized at EVAP Service Port, check shaded areas for leaks (soapy
water can be used for leak detection). Diagnostic
Tips for Late
Type EVAP
System
(Continued)

EVAP SYSTEM OPERATION INFORMATION ± EG005-01 April 27, 2001
Page 14 of 14
ECHO Canister and Tank Leak Check
A. Connect the Pressure Supply hose from the Pressure Test Kit to the Green EVAP
System Service Port located on the EVAP Purge VSV line in the engine
compartment.
B. Using the directions on the inside of the EVAP System Pressure Test Kit lid,
pressurize the EVAP system. Once pressurized, turn off the pump and seal the
system (Pressure Hold Switch to ªClosedº and Vent Switch to ªClosedº)
C. With system pressurized, check shaded areas for leaks (soapy water can be used
for leak detection).
Return Vehicle to Service
A. After performing checks and/or repairs, be sure to reconnect all lines and verify
that all plugs and hose pliers used for diagnosis have been removed.
B. For additional diagnostic procedures and information, refer to the appropriate
Repair Manual. Diagnostic
Tips for Late
Type EVAP
System
(Continued)

Toyota Supports ASE CertificationPage 1 of 5
EG013-02Title:
M.I.L. ON" P0440, P0441 & P0446
Models:
'98 ± '99 Camry & Solara
Technical Service
BULLETIN
July 12, 2002

Under certain driving conditions, some 1998 ± 1999 model year Camry and Solara
vehicles may exhibit a M.I.L. ªONº with DTCs P0440, P0441 and P0446 stored due to an
inoperative Vapor Pressure Sensor 3 way Vacuum Switching Valve (VSV). An improved
Vapor Pressure Sensor VSV has been developed to correct this condition.

1998 ± 1999 model year Camry & Solara vehicles.
PREVIOUS PART NUMBERCURRENT PART NUMBERPART NAMEQTY
90910±1210990910±12271Vapor Pressure Sensor VSV1
TOOLS & MATERIALPART NUMBERQUANTITY
Toyota Diagnostic Tester Kit*
010012711
12 Megabyte Diagnostic Tester Program Card
with version 9.01a Software (or later)*
01002593-0051
Hand Operated Vacuum PumpN/A1
Digital Volt Ohm Meter (DVOM)09082±00050
(Or Equivalent)1
* Essential SSTs.
NOTE:
Additional Diagnostic Tester Kits, Program Cards or SSTs may be ordered by calling
OTC at 1-800-933-8335.
OP CODEDESCRIPTIONTIMEOFPT1T2
178011
R & R Vacuum Switching Valve (4 Cylinder)0.4
90910 121097283178011R & R Vacuum Switching Valve (6 Cylinder)0.290910±121097283
Applicable Warranty*:
This repair is covered under the Toyota Comprehensive Warranty. This warranty is in
effect for 36 months or 36,000 miles, whichever occurs first, from the vehicle's
in-service date.
* Warranty application is limited to correction of a problem based upon a customer's specific complaint.
ENGINE
Introduction
Applicable
Vehicles
Parts
Information
Required Tools
& Material
Warranty
Information