Lexus ES300 (2002 year). Service manual - part 369

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-95

248

REPLACE FUEL TANK CAP ASSY

6

INSPECT FUEL TANK INLET PIPE SUB-ASSY

(a)

Remove the fuel tank cap.

(b)

Visually inspect the fuel inlet pipe for damage.

NG

REPLACE FUEL TANK INLET PIPE SUB-ASSY

(1)

Replace to fuel tank inlet pipe sub-assy.

(2)

After replace, perform ”EVAP SYS CHECK” by
hand-held  tester. (Go to step 2.)

OK

REPAIR OR REPLACE VACUUM HOSES(VAPOR PRESSURE SENSOR - FUEL TANK, FUEL TANK
-  VSV FOR PRESSURE SWITCHING VALVE)

(c)

Repair or replace to fuel tank cap assy.

(d)

After repair or replace, perform ”EVAP SYS CHECK” by hand-held tester. (Go to step 2)

7

CHECK FUEL HOSE(VSV FOR PRESSURE SWITCHING VALVE  -  CHARCOAL
CANISTER)

(a)

Check for proper connection of the fuel tank and fuel EVAP pipe (See page 

12-1

), fuel EVAP pipe and

fuel tube under the floor, fuel tube under the floor and charcoal canister.

(b)

Check the hose and tube for cracks, hole and damage.

NG

REPAIR OR REPLACE

OK

8

CHECK CHARCOAL CANISTER ASSY (See page 

12-6

)

NG

REPLACE CHARCOAL CANISTER ASSY

OK

A53763

VC

E2

A53769

E2

PTNK

05-96

-

DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

249

9

INSPECT ECM(CHECK VOLTAGE)

(a)

Turn the ignition switch ON.

(b)

Measure the voltage between terminals VC and E2 of the
ECM connector.
Voltage: 4.5 - 5.5 V

NG

CHECK AND REPLACE ECM

OK

10

INSPECT ECM(CHECK VOLTAGE)

(a)

Remove the fuel tank cap.

(b)

Turn the ignition switch ON.

(c)

Measure the voltage between terminals PTNK of the
ECM E6 connector and E2 of the ECM E10 connector.
Voltage: 3.0 - 3.6 V

OK

Go to step 12

NG

11

CHECK HARNESS AND CONNECTOR(VAPOR PRESSURE SENSOR - ECM)

NG

REPAIR OR REPLACE HARNESS AND
CONNECTOR

OK

REPLACE VAPOR PRESSURE SENSOR ASSY

12

CHECK FUEL TANK AND FUEL TANK OVER FILL CHECK VALVE FOR CRACKS
AND DAMAGE

NG

REPLACE FUEL TANK ASSY

OK

IT IS LIKELY THAT VEHICLE USER DID NOT PROPERLY CLOSE FUEL TANK CAP

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

Fig. 1

VSV for
CCV

VSV
for EVAP

ECM

Vapor Pressure
Sensor

Fuel Tank Over
Fill Check Valve

Fuel Tank

Charcoal Canister

VSV for
Pressure
Switching Valve

A10142

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-97

250

DTC

P0441

EVAPORATIVE EMISSION CONTROL
SYSTEM INCORRECT PURGE FLOW

DTC

P0446

EVAPORATIVE EMISSION CONTROL
SYSTEM VENT CONTROL MALFUNCTION

CIRCUIT DESCRIPTION

The vapor pressure sensor,

 

VSV for canister closed valve (CCV), VSV for pressure switching valve are used

to detect abnormalities in the evaporative emission control system.
The ECM decides whether there is an abnormality in the evaporative emission control system based on the
vapor pressure sensor signal.
DTCs P0441 and P0446 are recorded by the ECM when evaporative emissions leak from the components
within the dotted line in Fig. 1 below, or when there is a malfunction in either the VSV for EVAP, the VSV for
pressure switching valve, or in the vapor pressure sensor itself.

0560M-06

A54287

VSV for CCV

VSV for
Pressure Switching Valve

VSV for EVAP

Cold Start

ECT/IAT near same temp.

Negative
Pressure
Occurs

Tank & Canister
Leak Check

VSV for Pressure
Switching Valve, CCV
Testing

Open

Closed

Open

Closed

Open

Closed

Closed

Closed

Open

Open

P0441

P0440

P0446

05-98

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

251

P0441:

The ECM closes the CCV and opens the VSV for pressure switching valve causing vacuum to increase in
the entire EVAP system.
The ECM continues to operate the VSV for EVAP until the vacuum is increased to a specified point at which
time the ECM closes the VSV for EVAP.
If the vacuum did not increase, or if the vacuum increased beyond the specified limit, the ECM judges the
VSV for EVAP and related components to be faulty.

P0446:

When the vapor pressure rises to a specified point, the ECM opens the VSV for CCV. Pressure will increase
rapidly because of the air allowed into the system. No increase or an increase below specified rate of pressre
increase indicates a restriction on the air inlet side.
The ECM closes the VSV for pressure switching valve. This action blocks air entering the fuel tank side of
system. The pressure rise on the fuel tank side is no longer as great.
If there was no change in pressure, the ECM will conclude the VSV for pressure switching valve did not close.

DTC No.

DTC Detecting Condition

Trouble Area

P0441

Pressure in charcoal canister and fuel tank does not drop dur-
ing purge control (2 trip detection logic)

Vacuum hose cracks, holed blocked, damaged or discon-
nected ((1), (2),

 

(3), (4), (5), (6), (7), (8), (9), (10) and (11) in

Fig 1)

P0441

During purge cut-off, negative pressure incoming in the char-
coal canister and fuel tank will not stop. (2 trip detection logic)

Fig. 1)

Fuel tank cap incorrectly installed

Open or short in vapor pressure sensor

 

circuit

When VSV for pressure switching valve

 

is ON, ECM judges

that there is no continuity between vapor pressure sensor, fuel
tank and charcoal canister (2 trip detection logic)

Vapor pressure sensor

Open or short in VSV circuit for EVAP

VSV for EVAP

Open or short in VSV circuit for CCV

P0446

When VSV for pressure switching valve is turned OFF, pres-
sure in fuel tank is maintained at atmospheric pressure (2 trip
detection logic)

O en or short in VSV circuit for CCV

VSV for CCV

Open or short in VSV circuit for pressure switching valve

VSV for pressure switching valve

Fuel tank cracked holed or damaged

When VSV for CCV is ON, pressure in charcoal canister and
fuel tank is maintained at atmospheric pressure (2 trip detec-
tion logic)

Fuel tank cracked, holed or damaged

Charcoal canister cracked, holed or damaged

Fuel tank over fill check valve cracked damaged

ECM