Page 2745 of 4770

A07147
E2 (±) PTNK (+)
EngineStart
Stop
OFF ON OFF VSV for
ON
Vapor
Pressure
Sensor
VSV for
EVAP
5 sec.
Measure Voltage
± DIAGNOSTICSENGINE (1MZ±FE)
DI±325
560 Author: Date:
14 Check vacuum hoses between charcoal canister and VSV for vapor pressure
sensor, and vapor pressure sensor and VSV for vapor pressure sensor.
CHECK:
(a) Check that the vacuum hose is connected correctly.
(b) Check the vacuum hose for looseness and disconnection.
(c) Check the vacuum hose for cracks, hole, damage and blockage.
NG Repair or replace.
OK
15 Check charcoal canister.
PREPARATION:
(a) Connect the TOYOTA hand±held tester to the DLC3.
(b) Remove the fuel tank cap.
(c) Disconnect the VSV connector for vapor pressure sensor.
(d) Select the ACTIVE TEST mode on the TOYOTA
hand±held tester.
(e) Start the engine.
(f) VSV for EVAP is ON by the TOYOTA hand±held tester
and remains on for 5 sec.
CHECK:
Measure voltage between terminals PTNK and E2 of ECM con-
nectors 5 sec. after switching VSV for EVAP from ON to OFF.
OK:
Voltage: 2.5 V or less
NG Replace charcoal canister.
OK
Page 2746 of 4770
DI±326
± DIAGNOSTICSENGINE (1MZ±FE)
561 Author: Date:
16 Remove charcoal canister and check it (See page EC±6).
NG Replace charcoal canister.
OK
17 Check fuel tank over fill check valve (See page EC±2).
NG Replace fuel tank over fill check valve or fuel
tank.
OK
Check and replace ECM (See page IN±31).
OBD II scan tool (excluding TOYOTA hand±held tester)
1 Check VSV connector for EVAP, VSV connector for vapor pressure sensor and
vapor pressure sensor connector for looseness and disconnection.
NG Repair or connect VSV or sensor connector.
OK
2 Check vacuum hoses (1), (4), (5), (6) (7) and (8) on Page DI±311).
CHECK:
(a) Check that the vacuum hose is connected correctly.
(b) Check the vacuum hose for looseness and disconnection.
(c) Check the vacuum hose for cracks, hole, damage and blockage.
NG Repair or replace.
OK
Page 2747 of 4770
± DIAGNOSTICSENGINE (1MZ±FE)
DI±327
562 Author: Date:
3 Check voltage between terminals VC and E2 of ECM connector
(See page DI±311, step 9).
NG Check and replace ECM (See page IN±31).
OK
4 Check voltage between terminals PTNK and E2 of ECM connectors
(See page DI±311, step 10).
OK Go to step 6.
NG
5 Check for open and short in harness and connector between vapor pressure
sensor and ECM (See page IN±31).
NG Repair or replace harness or connector.
OK
Replace vapor pressure sensor.
Page 2748 of 4770
A07148
ON
EVA1
ON OFF
VSV is ON VSV is OFF
E
FAir Air
E
F
DI±328
± DIAGNOSTICSENGINE (1MZ±FE)
563 Author: Date:
6 Check VSV for EVAP.
PREPARATION:
(a) Remove the glove compartment (See page SF±73).
(b) Turn the ignition switch ON.
CHECK:
Check VSV function.
(1) Connect between terminal EVA1 of the ECM
connector and body ground (ON).
(2) Disconnect between terminal EVP of the ECM con-
nector and body ground (OFF).
OK:
(1) VSV is ON:
Air from pipe E is flowing out through pipe F.
(2) VSV is OFF:
Air does not flow from pipe E to pipe F.
OK Go to step 9.
NG
7 Check operation of VSV for EVAP (See page SF±58).
OK Go to step 9.
NG
Replace VSV and charcoal canister, and then clean the vacuum hoses between throttle body and
VSV for EVAP, and VSV for EVAP and charcoal canister.
Page 2749 of 4770
A07149
ON
TPC
OFFON
VSV is ON
VSV is OFF
Air
E
FG Air
G E
F
± DIAGNOSTICSENGINE (1MZ±FE)
DI±329
564 Author: Date:
8 Check for open and short in harness and connector between EFI main relay
(Marking: EFI) and VSV for EVAP and ECM (See page IN±31).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN±31).
9 Check VSV for vapor pressure sensor.
PREPARATION:
(a) Remove the glove compartment (See page SF±73).
(b) Turn the ignition switch ON.
CHECK:
Check VSV function.
(1) Connect between terminal TPC of the ECM connec-
tor and body ground (ON).
(2) Disconnect between terminal TPC of the ECM
connector and body ground (OFF).
OK:
(1) VSV is ON:
Air from pipe E is flowing out through pipe F.
(2) VSV is OFF:
Air from pipe E flows out through pipe G.
OK Check and replace charcoal canister
(See page EC±6).
NG
Page 2750 of 4770
DI±330
± DIAGNOSTICSENGINE (1MZ±FE)
565 Author: Date:
10 Check operation of VSV for vapor pressure sensor (See page SF±62).
OK Go to step 11.
NG
Replace VSV and clean the vacuum hoses between charcoal canister and VSV for vapor pressure
sensor, and VSV for vapor pressure sensor and vapor pressure sensor, and then check the char-
coal canister.
11 Check for open and short in harness and connector between EFI main relay
(Marking: EFI) and VSV for vapor pressure sensor, and VSV for vapor pressure
sensor and ECM (See page IN±31).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN±31).
12 Check the fuel tank over fill check valve (See page EC±6).
NG Replace fuel tank over fill check valve or fuel
tank.
OK
Check and replace charcoal canister
(See page EC±6).
Page 2751 of 4770

A01655
Charcoal CanisterVapor Pressure
Sensor
VSV for Vapor
Pressure Sensor
Fuel Tank VSV
for EVAPECM
Fuel Tank Over
Fill Check Valve
± DIAGNOSTICSENGINE (1MZ±FE)
DI±331
566 Author: Date:
DTC P0450 Evaporative Emission Control System
Pressure Sensor Malfunction
DTC P0451 Evaporative Emission Control System
Pressure Sensor Range/Performance
CIRCUIT DESCRIPTION
The vapor pressure sensor and VSV for vapor pressure sensor are used to detect abnormalities in the evap-
orative emission control system.
The ECM decides whether there is an abnormality in the evaporative emission control system based on the
vapor pressure sensor signal.
DTC P0450 or p0451 is recorded by the ECM when the vapor pressure sensor malfunction.
DTC No.DTC Detecting ConditionTrouble Area
P0450
10 seconds or more after engine starting condition (a) or (b)
continues for 7 seconds or more:
(2 trip detection logic)
(a) Vapor Pressure Sensor Value
< ±3.5 kPa (±26 mmHg,
±1.0 in.Hg)
(b) Vapor Pressure Sensor Value 1.5 kPa (15 mmHg,
0.4 in.Hg)
Open or short in vapor pressure sensor circuit
V
P451
Vapor pressure sensor output extremely changes under
conditions of (a), (b) and (c):
(2 trip detection logic)
(a) Vehicle speed: 0 km/h (0 mph)
(b) Engine speed: Idling
(c) VSV for vapor pressure sensor is ON.Vapor pressure sensor
ECM
DI1K5±03
Page 2752 of 4770

DI±332
± DIAGNOSTICSENGINE (1MZ±FE)
567 Author: Date:
WIRING DIAGRAM
Refer to DTC P0440 (Evaporative Emission Control Malfunction) on page DI±311.
INSPECTION PROCEDURE
HINT:
If DTCs P0441, P0446, P0450 or P0451 is output after DTC P0440, first troubleshoot DTCs P0441,
P0446 ,P0450 or P0451. If no malfunction is detected, troubleshoot DTC P0440 next.
Read freeze frame data using TOYOTA hand±held tester or OBD II scan tool. Because freeze frame
records the engine conditions when the malfunction is detected, when troubleshooting it is useful for
determining whether the vehicle was running or stopped, the engine warmed up or not, the air±fuel
ratio lean or rich, etc. at the time of the malfunction.
When the ENGINE RUN TIME in the freeze frame data is less than 200 seconds, carefully check the
VSV for EVAP, charcoal canister and vapor pressure sensor.
1 Check voltage between terminals VC and E2 of ECM connector
(See page DI±311, step 9).
NG Check and replace ECM (See page IN±31).
OK
2 Check voltage between terminals PTNK and E2 of ECM connectors
(See page DI±311, step 10).
OK Check and replace ECM (See page IN±31).
NG
3 Check for open and short in harness and connector between vapor pressure
sensor and ECM (See page IN±31).
NG Repair or replace harness or connector.
OK
Replace vapor pressure sensor.