2001 TOYOTA AVALON Service Repair Manual

A11423
Engine Room J/B
EFI No.2
Fuse
- DIAGNOSTICSENGINE
DI-151
307 Author
: Date
:
2001 AVALON (RM808U)
OK
8 Check EFI No.2 fuse.
PREPARATION:
Remove the EFI No.2 fuse from the engine room J/B.
CHECK:
Check the continuity of the EFI No.2 fuse.
OK:
Continuity
NG Check for short in all harness and components
connected to EFI No.2 fuse.
OK
9 Check EFI main relay (Marking: EFI) (See page SF-60).
NG Replace EFI main relay.
OK
10 Check for open and short in harness and connector between terminal MREL of
ECM and body ground (See page IN-30).
NG Repair or replace harness or connector.
OK
Check and repair harness or connector be-
tween EFI No.1 fuse and battery.

A11425
EFI No.1
FL
MainIG Switch
AM2
BatteryEFI Relay
C/OPN Relay
Fuel Pump
ST
RelayStarter Park/ Neutral
Position SwitchECM
FC
Tr
STA
NE (STA Signal)
(NE Signal) MAINMREL
IGSW
ST DI-152
- DIAGNOSTICSENGINE
308 Author
: Date
:
2001 AVALON (RM808U)
Fuel Pump Control Circuit
CIRCUIT DESCRIPTION
In the diagram below, when the engine is cranked, current flows from terminal ST of the ignition switch to
the starter relay (Marking: ST) coil and also current flows to terminal STA of ECM (STA signal).
When the STA signal and NE signal are input to the ECM, Tr is turned ON, current flows to coil of the circuit
opening relay (Marking: C/OPN), the relay switches on, power is supplied to the fuel pump and the fuel pump
operates.
While the NE signal is generated (engine running), the ECM keeps Tr ON (circuit opening relay ON) and the
fuel pump also keeps operating.
DI6TE-01

A11672
From
Terminal
MREL of
ECM From
Battery1 5
2 B-R3
C/OPN Relay Driver Side R/B No.6
6
66 6 B-R 1
IF1 W-R
W-B
2C
2F13
EFI
No.1 AM2
EFI Relay 5
1B
EDEngine Room J/B
43
22B
1 2G
46 7
2C 2
BK 7 4
IF1ECM
E01
ID2E8
Fuel
Pump
AL-B
W-BJ11
J/CFC
G-B3
5 41
L-B B-O IG SwitchW-B
W-R
L-O
BE6653A02330
A02405
ON
- DIAGNOSTICSENGINE
DI-153
309 Author
: Date
:
2001 AVALON (RM808U)
WIRING DIAGRAM
INSPECTION PROCEDURE
TOYOTA hand-held tester:
1 Connect TOYOTA hand-held tester, and check operation of fuel pump.
PREPARATION:1
(a) Connect the TOYOTA hand-held tester to the DLC3.
(b) Turn the ignition switch ON and push the TOYOTA hand-
held tester main switch ON.
(c) Use the ACTIVE TEST mode to operate the fuel pump.
CHECK:
Check that the pulsation damper screw rises up when the fuel
pump is operated by the TOYOTA hand-held tester.
OK:
The pulsation damper screw rises up.
OK Check for starter signal circuit
(See page DI-142).
NG

A02064
ON
FC
(+) (-)
DI-154
- DIAGNOSTICSENGINE
310 Author
: Date
:
2001 AVALON (RM808U)
2 Check for ECM power source circuit (See page DI-148).
NG Repair or replace.
OK
3 Check circuit opening relay (Marking: C/OPN) (See page SF-63).
NG Replace circuit opening relay.
OK
4 Check voltage between terminal FC of ECM connector and body ground.
PREPARATION:
(a) Remove the glove compartment (See page SF-83).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal FC of the ECM connec-
tor and body ground.
OK:
Voltage: 9 - 14 V
OK Go to step 5.
NG
Check for open in harness and connector between EFI main relay (Marking: EFI) and circuit open-
ing relay (Marking: C/OPN), and circuit opening relay and ECM (See page IN-30).
5 Check fuel pump (See page SF-6).
NG Repair or replace fuel pump.

A02042
ON
FC
- DIAGNOSTICSENGINE
DI-155
311 Author
: Date
:
2001 AVALON (RM808U)
OK
6 Check for open in harness and connector between circuit opening relay (Mark-
ing: C/OPN) and fuel pump, and fuel pump and body ground
(See page IN-30).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN-30).
OBD II scan tool (excluding TOYOTA hand-held tester):
1 Check operation of fuel pump.
PREPARATION:
(a) Remove the glove compartment (See page SF-82).
(b) Turn the ignition switch ON.
CHECK:
(a) Connect between terminal FC of the ECM connector and
body ground.
(b) Check that the pulsation damper screw rises up when
connecting between terminal FC of the ECM connector
and body ground.
OK:
The pulsation damper screw rises up.
OK Check for starter signal circuit
(See page DI-142).
NG
2 Check for ECM power source circuit (See page DI-148).

A02064
ON
FC
(+) (-)
DI-156
- DIAGNOSTICSENGINE
312 Author
: Date
:
2001 AVALON (RM808U)
NG Repair or replace.
OK
3 Check circuit opening relay (Marking: C/OPN) (See page SF-63).
NG Replace circuit opening relay.
OK
4 Check voltage between terminal FC of ECM connector and body ground.
PREPARATION:
(a) Remove the glove compartment (See page SF-83).
(b) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal FC of the ECM connec-
tor and body ground.
OK:
Voltage: 9 - 14 V
OK Go to step 5.
NG
Check for open in harness and connector between EFI main relay (Marking: EFI) and circuit open-
ing relay (Marking: C/OPN), and circuit opening relay and ECM (See page IN-30).
5 Check fuel pump (See page SF-6).
NG Repair or replace fuel pump.
OK

- DIAGNOSTICSENGINE
DI-157
313 Author
: Date
:
2001 AVALON (RM808U)
6 Check for open in harness and connector between circuit opening relay (Mark-
ing: C/OPN) and fuel pump, and fuel pump and body ground
(See page IN-30).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN-30).

A06092
1
3
5
24
6 IACV No.2IACV No.1, No.2 closed (VSV: OFF)
Throttle Valve30°
3,700 rpm
Engine Speed
Throttle Valve
Opening Angle
FI7011 FI6570
IACV No.1
2,700 rpmIACV No.1 open (VSV: ON)
IACV No.2 closed (VSV: OFF)
IACV No.1, No.2 open (VSV: ON)
A11667
From BatteryEngine Room J/B
2B 2G
2F
2B
2
4
1 EFI
No.1EFI Relay
W-B
B-W 9
E01ACISE4 R-Y
2 VSV for ACIS No.1
ED17
L-O B
4 EFI
No.21
2
From
Terminal
MREL of
ECME01
ACI1E5 15
B-W B-WECM
VSV for ACIS No.2W-R 1 2
53
- DIAGNOSTICSENGINE
DI-145
301 Author
: Date
:
2001 AVALON (RM808U)
IACV Control Circuit
CIRCUIT DESCRIPTION
This circuit opens and closes the IACV (Intake Air Control Valve) in response to the engine load in order to
increase the intake efficiency (ACIS: Acoustic Control Induction System).
When the engine speed is 3,700 rpm or less and the throttle valve opening angle is 30° or more, the ECM
turns the two VSV ON or OFF and operate the IACV.
WIRING DIAGRAM
DI08E-09