TOYOTA PRIUS 2001 Service Repair Manual

B11798
Air Cleaner
Throttle Valve
VSV for
EVAP
Purge Line
VSV for Purge Flow
Switching Valve
Charcoal
Canister
EVAP Line
Fuel Tank Vapor Pressure
Sensor Trap Filter Fresh Air
Valve
Canister Closed
Valve Filler Pipe
EC±4
± EMISSION CONTROLPARTS LAYOUT AND SCHEMATIC DRAWING
2001 PRIUS (RM778U)

EC0HV±01
B04812
Gasket
B06544
Vacuum
Gauge
F12396
TOYOTA Hand±held Tester
B11799
± EMISSION CONTROLEVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM
EC±7
2001 PRIUS (RM778U)
INSPECTION
1. REMOVE EXHAUST TAIL PIPE AND HEATED INSULA-
TOR (See page EM±84)
2. INSPECT LINES AND CONNECTORS
Visually check for loose connections, sharp bends or damage.
3. INSPECT FUEL TANK FILLER PIPE
Visually check for deformation, cracks or fuel leakage.
4. INSPECT FUEL TANK CAP
Visually check if the cap and/or gasket are deformed or dam-
aged.
If necessary, repair or replace the cap.
5. INSPECT EVAP SYSTEM LINE
(a) Warm up the engine and stop the engine.
Allow the engine to warm up to normal operating tempera-
ture.
(b) Install a vacuum gauge (EVAP control system test equip-
ment vacuum gauge) to the EVAP service port on the
purge line.
(c) TOYOTA hand±held tester:
Forced driving of the VSV for the EVAP.
(1) Connect a TOYOTA hand±held tester to the DLC3.
(2) Start the engine.
(3) Push the TOYOTA hand±held tester main switch
ON.
(4) Use the ACTIVE TEST mode on the TOYOTA
hand±held tester to operate the VSV for the EVAP.
(d) If you have no TOYOTA hand±held tester:
Forced driving of the VSV for the EVAP.
(1) Disconnect the VSV connector for the EVAP.
(2) Connect the positive (+) and negative (±) leads from
the battery to the VSV terminals for the EVAP.
(3) Start the engine.

B06545
B11800
B06546
Pressure
Gauge
Pressure EC±8
± EMISSION CONTROLEVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM
2001 PRIUS (RM778U)
(e) Check the vacuum at idle.
Vacuum:
Maintain at 0.368 ± 19.713 in. Hg (5 ± 268 in.Aq) for
over 5 seconds
HINT:
If the vacuum does not change, you can conclude that the hose
connecting the VSV to the service port has come loose or is
blocked, or the VSV is malfunctioning.
(f) If you have TOYOTA hand±held tester:
Conclude forced driving of the VSV for the EVAP.
(1) Stop the engine.
(2) Disconnect the TOYOTA hand±held tester from the
DLC3.
(g) If you have no TOYOTA hand±held tester:
Conclude forced driving of the VSV for the EVAP.
(1) Stop the engine.
(2) Disconnect the positive (+) and negative (±) leads
from the battery, and from the VSV terminals for the
EVAP.
(3) Connect the VSV connector for the EVAP.
(h) Disconnect the vacuum gauge from the EVAP service
port on the purge line.
(i) Connect a pressure gauge to the EVAP service port on
the purge line.
(j) Check the pressure.
(1) Close off the air drain hose at the marked position
of the canister with a hose clipper or similar instru-
ment.
(2) Add the pressure (13.5 ± 15.5 in.Aq) from the EVAP
service port.
Pressure:
2 minutes after the pressure is added, the gauge
should be over 7.7 ± 8.8 in.Aq.
HINT:
If you can't add pressure, you can conclude that the hose con-
necting the VSV±canister±fuel tank has slipped off or the VSV
is open.

F12396
TOYOTA
Hand±held Tester
DLC3
B12247
CCV
ECM
B06545
B12239
± EMISSION CONTROLEVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM
EC±9
2001 PRIUS (RM778U)
6. CHECK AIRTIGHTNESS IN FUEL TANK AND FILLER
PIPE
(a) TOYOTA hand±held tester:
Forced driving of the VSV for the canister closed valve
(CCV).
(1) Connect a TOYOTA hand±held tester to the DLC3.
(2) Turn the ignition switch ON.
(3) Push the TOYOTA hand±held tester mode on the
TOYOTA hand±held tester to operate the VSV for
the canister closed valve (CCV).
(b) If you have no TOYOTA hand±held tester:
Forced driving of the canister closed valve (CCV).
(1) Remove the connector cover from the ECM.
(2) Turn the ignition switch ON.
(3) Connect the between terminal CCV of the ECM
connector and body ground.
(c) Add the pressure from the EVAP service port to 1.6 kPa
(16.3 kgf/cm
2, 0.232 psi).
(d) Check that the pressure can be held for 30 seconds.
(e) Visually check the fuel tank and filler pipes.
(f) Check each connection of hoses and pipes.
If there is abnormality, replace the fuel tank and filler pipe.
7. CHECK AIR INLET LINE
(a) Disconnect the air inlet line hose from the fresh air valve.

B11801
B12240
B11803
B11804
B11805
Port APort C
Port B
EC±10
± EMISSION CONTROLEVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM
2001 PRIUS (RM778U)
(b) Disconnect the air inlet hose from the air cleaner case.
(c) Blow air into the air inlet line hose.
(d) Check that the air flows from the air inlet line hose.
(e) Visually check the air inlet line hoses and pipes.
(f) Check each connection of hoses and pipes.
If there is abnormality, replace the air inlet line hose and pipe.
8. REMOVE CHARCOAL CANISTER ASSEMBLY
(a) Remove the fuel tank (See page SF±17)
(b) Disconnect the 3 hoses from the charcoal canister.
(c) Remove the 2 bolts and charcoal canister from the fuel
tank.
(d) Remove the 2 bolts and VSV for purge flow switching from
the charcoal canister.
9. INSPECT CHARCOAL CANISTER
(a) Visually check the charcoal canister for cracks or dam-
age.
(b) While holding port C closed, using low pressure com-
pressed air (4.9 kPa (50 gf/cm
2, 0.71 psi), blow into port
A and check that air flows without resistance from the port
B.

B11806
Port APort C
Port B
B11807
B11808
B11809
B11810
Port A
Port B
± EMISSION CONTROLEVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM
EC±11
2001 PRIUS (RM778U)
(c) Using low pressure compressed air (4.9 kPa (50 gf/cm2,
0.71 psi), blow into port A and check that air flows without
resistance from the other ports.
If a problem is found, replace the charcoal canister.
10. REINSTALL CHARCOAL CANISTER ASSEMBLY
11. REMOVE TRAP FILTER AND FRESH AIR VALVE
(a) Remove the fuel tank (See page SF±17).
(b) Disconnect the air inlet hoses from the VSV for canister
closed valve.
(c) Disconnect the connector from the fresh air valve.
(d) Remove the bolt and disconnect the air opening valve
from the VSV for canister closed valve.
(e) Remove the 2 bolts and VSV for canister closed valve
with the trap filter.
(f) Remove the 2 bolts and trap filter from the VSV for canis-
ter closed valve.
12. INSPECT TRAP FILTER
(a) Visually check the trap filter for cracks or damage.
(b) Inspect the trap filter operation.
Blow air into port A, check that the air flows from port B.
If a problem is found, replace the trap filter.

B11811
Port APort C
Port B
EC±12
± EMISSION CONTROLEVAPORATIVE EMISSION (EVAP) CONTROL SYSTEM
2001 PRIUS (RM778U)
13. INSPECT FRESH AIR VALVE
(a) Visually check the fresh air valve for cracks or damage.
(b) Inspect the fresh air valve operation.
Blow air into port A, check that the air flows from port B
and C.
If a problem is found, replace the fresh air valve.
14. REINSTALL TRAP FILTER AND FRESH AIR VALVE

EC0HW±01
F12396
TOYOTA
Hand±held Tester
DLC3
B11812
B11813
± EMISSION CONTROLTHREE±WAY CATALYTIC CONVERTER (TWC)
SYSTEMEC±13
1213 Author: Date:
2001 PRIUS (RM778U)
THREE±WAY CATALYTIC
CONVERTER (TWC) SYSTEM
INSPECTION
1. CHECK TWC FOR DENTS OR DAMAGE
If any port of the heat insulator is damaged to the extent that it
contacts the three±way catalytic converter, repair or replace it.
2. CHECK EXHAUST PIPE CONNECTIONS FOR LOOSE-
NESS OR DAMAGE
3. CHECK EXHAUST PIPE CLAMPS FOR WEAKNESS,
CRACKS OR DAMAGE
4. CHECK HEAT INSULATOR FOR DAMAGE
5. CHECK FOR ADEQUATE CLEARANCE BETWEEN
EXHAUST SYSTEM AND HEAT INSULATOR ON THE
BODY
6. INSPECT HC ABSORBER AND CATALYST SYSTEM
(a) Warm up the engine.
(b) TOYOTA hand±held tester:
Forced driving of the VSV for the HC absorber and cata-
lyst system.
(1) Connect a TOYOTA hand±held tester to the DLC3.
(2) Start the engine.
(3) Push the TOYOTA hand±held tester mode on the
TOYOTA hand±held tester to operate the VSV for
the HC absorber and catalyst system.
(c) If you have no TOYOTA hand±held tester:
Forced driving of the VSV for the TOYOTA HC absorption
catalyst system.
(1) Disconnect the VSV connector for the TOYOTA HC
absorption catalyst system.
(2) Connect the positive (+) and negative (±) leads from
the battery to the VSV.
(3) Start the engine.
(d) Check that the rod of the actuator is pulled and the valve
is operating.
If not in operation, check the vacuum hose line or VSV, actuator.

B11814
B11831
EC±14± EMISSION CONTROLTHREE±WAY CATALYTIC CONVERTER (TWC)
SYSTEM
1214 Author: Date:
2001 PRIUS (RM778U)
7. INSPECT ACTUATOR
(a) Remove the front exhaust pipe.
(b) Remove the actuator from the front exhaust pipe.
(c) Connect the MITYVAC (hand±held vacuum pump) to the
actuator port.
(d) Apply vacuum (more than 33.3 kPa, 250 mmHg, 9.83
in.Hg), make sure that the rod is retracted.
If the not, replace the actuator.
(e) Disconnect the MITYVAC (hand±held vacuum pump)
from the actuator port.
8. INSPECT VALVE OPERATION
(a) Turn the valve stay by hand and ensure that it can turn.
If the not, replace the front exhaust pipe.
(b) Install the actuator to the front exhaust pipe.
(c) Install the front exhaust pipe.

SF1KN±01
± SFISFI SYSTEM
SF±1
1215 Author: Date:
2001 PRIUS (RM778U)
SFI SYSTEM
PRECAUTION
1. BEFORE WORKING ON THE FUEL SYSTEM , DIS-
CONNECT THE NEGATIVE (±) TERMINAL CABLE
FROM THE BATTERY AND HV BATTERY SERVICE
PLUG
HINT:
Any diagnostic trouble code retained by the computer will be
erased when the negative (±) terminal cable is removed from
the battery. Therefore, if necessary, read the diagnosis before
removing the negative (±) terminal cable from the battery.
2. DO NOT SMOKE OR WORK NEAR AN OPEN FLAME
WHEN WORKING ON THE FUEL SYSTEM
3. KEEP GASOLINE AWAY FROM RUBBER OR
LEATHER PARTS
4. MAINTENANCE PRECAUTIONS
(a) In event of engine misfire, these precautions should be
taken.
(1) Check proper connection to battery terminals, etc.
(2) After repair work, check that the ignition coil termi-
nals and all other ignition system lines are recon-
nected securely.
(3) When cleaning the engine compartment, be espe-
cially careful to protect the electrical system from
water.
(b) Precautions when handling oxygen sensor.
(1) Do not allow oxygen sensor to drop or hit against an
object.
(2) Do not allow the sensor to come into contact with
water.
If vehicle is Equipped with Mobile Radio System (HAM, CB,
etc.)
If the vehicle is equipped with a mobile communication system,
refer to the precaution in the IN section.
5. AIR INDUCTION SYSTEM
(a) Separation of the engine oil dipstick, oil filler cap, PCV
hose, etc. may cause the engine to run out of turn.
(b) Disconnection, looseness or cracks in the parts of the air
induction system between the throttle body and cylinder
head will allow air suction and cause the engine to run out
of turn.
6. ELECTRONIC CONTROL SYSTEM
(a) Before removing SFI wiring connectors, terminals, etc.,
first disconnect the power by either turning the ignition
switch to LOCK or disconnecting the negative (±) terminal
cable from the battery.
HINT:
Always check the diagnostic trouble code before disconnecting
the negative (±) terminal cable from the battery.