2001 TOYOTA AVALON Service Repair Manual

DI-98
- DIAGNOSTICSENGINE
254 Author
: Date
:
2001 AVALON (RM808U)
WIRING DIAGRAM
Refer to DTC P0440 or P0442 on page DI-74.
INSPECTION PROCEDURE
HINT:

If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440 or P0442, first trouble shoot DTC
P0441, P0446 P0450 or P0451. If no malfunction is detected, troubleshoot DTC P0440 or P0442 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 was warmed up or not, the air-fuel
ratio was 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-74, step 9).
NG Check and replace ECM (See page IN-30).
OK
2 Check voltage between terminals PTNK and E2 of ECM connectors (See page
DI-74, step 10).
OK Check and replace ECM (See page IN-30).
NG
3 Check for open and short in harness and connector between vapor pressure sen-
sor
and ECM (See page IN-30).
NG Repair or replace harness or connector.
OK
Replace vapor pressure sensor.

A00022
4-Pulse
Engine
ECM
Multi Display From
Speed Sensor4-Pulse
ABS Actuator
& ECU
A11086
Multi Display
18
M3 E73F V-W V-WECM
SPD5 V
122
3C 1J/B No.3
- DIAGNOSTICSENGINE
DI-99
255 Author
: Date
:
2001 AVALON (RM808U)
DTC P0500 Vehicle Speed Sensor Malfunction
CIRCUIT DESCRIPTION
This sensor is mounted in the combination meter. It contains a magnet which is rotated by the speedometer
cable.
Turning the reed switch ON and OFF 4 times for every revolution of the speedometer.
It is then transmitted to the Engine ECM. The Engine ECM determines the vehicle speed based on the fre-
quency of these pulse signals.
DTC No.DTC Detecting ConditionTrouble Area
No vehicle speed sensor signal to Engine & ECT ECU under
Combination meter
P0500/61
No vehicle speed sensor signal to Engine & ECT ECU under
th f ll i diti (2 t i d t ti l i )

Combination meter
Ohtid iitP0500/61the following conditions: (2 trip detection logic)
Open or short in speed sensor circuitg( g)
Vehicle is being driven
ECM
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
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 was warmed up or not, the air-fuel ratio was lean
or rich, etc. at the time of the malfunction.
DI082-09

A02030
E7 Connector
SPD
A02029
E7 ConnectorON
SPD(-) (+)
DI-100
- DIAGNOSTICSENGINE
256 Author
: Date
:
2001 AVALON (RM808U)
1 Check operation of speedometer.
CHECK:
Drive the vehicle and check if the operation of the speedometer in the combination meter is normal.
HINT:
The vehicle speed sensor is operating normally if the speedometer display is normal.
NG Check speedometer circuit (See page BE-43).
OK
2 Check for short in harness and connector between terminal SPD of ECM and
body ground.
PREPARATION:
(a) Remove the glove compartment (See page SF-83).
(b) Disconnect the E7 connector from the ECM.
CHECK:
Check the continuity between terminal SPD of the ECM con-
nector and body ground.
OK:
No continuity (1 MW or higher)
NG Repair or replace harness or connector.
OK
3 Check voltage between terminal SPD of ECM connector and body ground.
PREPARATION:
(a) Remove the glove compartment (See page SF-83).
(b) Disconnect the E7 connector from the ECM.
(c) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal SPD of the ECM con-
nector and body ground.
OK:
Voltage: 9 - 14 V
NG Check for open in harness and connector be-
tween J/B No.3 and ECM (See page IN-30).

- DIAGNOSTICSENGINE
DI-101
257 Author
: Date
:
2001 AVALON (RM808U)
OK
4 Check for open in harness and connector between J/B No.3 and combination
meter (See page IN-30).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN-30).

P01559
Throttle Valve
From
Air
Cleaner
Signal
ECM
ValveIAC Valve
To Cylinders Intake Air Chamber
A11664
From Battery2G1 2
4 EFI
No.1EFI Relay
1 23
52A
2B 2F
J7
J/C IAC Valve
G-B
BR
21
3E4ECM
RSO
E01
EC26
A B-W
L-O
BRA
4EFI
No.2
B
W-B
EDEngine Room J/B
EBA
From
Terminal
MREL of
ECM
DI-102
- DIAGNOSTICSENGINE
258 Author
: Date
:
2001 AVALON (RM808U)
DTC P0505 Idle Control System Malfunction
CIRCUIT DESCRIPTION
The rotary solenoid type IAC valve is located in front of the in-
take air chamber and intake air bypassing the throttle valve is
directed to the IAC valve through a passage.
In this way the intake air volume bypassing the throttle valve is
regulated, controlling the engine speed.
The ECM operates only the IAC valve to perform idle-up and
provide feedback for the target idling speed.
DTC No.DTC Detecting ConditionTrouble Area
P0505Idle speed continues to vary greatly from the target speed (2
trip detection logic)

Open or short in IAC valve circuit

IAC valve is stuck or closed

Open or short in A/C signal circuit

Air induction system

ECM
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
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 was warmed up or not, the air-fuel ratio was lean
or rich, etc. at the time of the malfunction.
DI083-09

A07628
ON
RSOE4 Connector
(+) (-)
- DIAGNOSTICSENGINE
DI-103
259 Author
: Date
:
2001 AVALON (RM808U)
1 Check idle speed.
When using TOYOTA hand-held tester:
PREPARATION:
(a) Warm up the engine to normal operating temperature.
(b) Switch off all the accessories.
(c) Switch off the A/C.
(d) Shift transmission into the N range or neutral position.
(e) Connect the TOYOTA hand-held tester to the DLC3 on the vehicle and select the ACTIVE TEST
mode.
CHECK:
Check the difference of the engine speed between the ones, less than 5 sec. and more than 5 sec. after
switching the TE1 from OFF to ON by the TOYOTA hand-held tester.
OK:
Difference of engine speed: More than 100 rpm
When not using TOYOTA hand-held tester:
PREPARATION:
(a) Warm up the engine to normal operating temperature.
(b) Switch off all the accessories.
(c) Switch off the A/C.
(d) Shift transmission into the N range or neutral position.
(e) Connect the OBDII scan tool to DLC3 on the vehicle.
(f) Using SST, connect terminals TE1 and E1 of the DLC1.
SST 09843-18020
CHECK:
Check the difference of engine speed between the ones, less than 5 sec. and more than 5 sec. after connect-
ing terminals TE1 and E1 of the DLC1.
OK:
Difference of engine speed: More than 100 rpm
OK Go to step 6.
NG
2 Check voltage between terminal RSO of ECM connector and body ground.
PREPARATION:
(a) Remove the glove compartment (See page SF-83).
(b) Disconnect the E4 connector from the ECM.
(c) Turn the ignition switch ON.
CHECK:
Measure the voltage between terminal RSO of the ECM con-
nector and body ground.
OK:
Voltage: 9 - 14 V

DI-104
- DIAGNOSTICSENGINE
260 Author
: Date
:
2001 AVALON (RM808U)
OK Go to step 4.
NG
3 Check IAC valve (See page SF-43).
NG Replace IAC valve.
OK
Check for open and short in harness and connector between engine room J/B and IAC valve, and
IAC valve and ECM (See page IN-30).
4 Check operation of IAC valve (See page SF-46).
NG Repair or replace IAC valve.
OK
5 Check blockage of IAC valve and passage to bypass throttle valve.
NG Repair or replace IAC valve.
OK
Check and replace ECM (See page IN-30).
6 Check for A/C signal circuit (See page DI-824).
NG Repair or replace.

- DIAGNOSTICSENGINE
DI-105
261 Author
: Date
:
2001 AVALON (RM808U)
OK
Check air induction system
(See page SF-1).