TOYOTA AVALON 2001 Service Repair Manual

DI-132
- DIAGNOSTICSENGINE
288 Author
: Date
:
2001 AVALON (RM808U)
Check and replace ECM (See page IN-30).
4 Check VVT controller assembly.
PREPARATION:
(a) Remove the timing belt (See page EM-15).
(b) Remove the cylinder head cover.
(c) Remove the OCV (See page EM-31).
(d) Drain oil into the VVT controller assembly (See page EM-31).
CHECK:
Check whether the oil into VVT controller assembly is drained or not.
OK:
The oil into VVT controller assembly is drained.
NG Replace VVT controller assembly, and then go
to step 5.
OK
5 Check OCV (See page SF-51).
NG Replace OCV, and then go to step 6.
OK
6 Check blockage of OCV, oil check valve and oil pipe No.1.
NG Repair or replace.
OK
7 Check whether or not DTC P1349/P1354 is stored.
PREPARATION:
(a) Clear the DTC (See page DI-3).
(b) Perform simulation test.

- DIAGNOSTICSENGINE
DI-133
289 Author
: Date
:
2001 AVALON (RM808U)
CHECK:
Check whether or not DTC P1349/P1354 is stored (See page DI-3).
OK:
DTC P1349/P1354 is not stored.
OK VVT system is OK.*
*: DTCs P1349 and P1354 are also output after the foreign ob-
ject is caught in some part of the system in the engine oil and
the system returns to normal in a short time. As ECM controls
so that foreign objects are ejected, there is no problem about
VVT. There is also no problem since the oil filter should get the
foreign object in the engine oil.
NG
Replace ECM.

A11416
Fusible
Link
Block
FL
Main
BatteryStop Light
Switch
ALT
B
F10
F6STOP
R
211D 1B
1E
45
Light
Failure
Sensor 7
2
To Stop LightE8 15ECM
STP
E1 Driver Side J/B
3 11
W
1 1
16
4C 3C
3164F3F 3
5IK1 1D 1
1GG-W
G-WDriver Side J/B
J/B No.3
J/B No.4
G-W
G-W G-W G-W
DI-134
- DIAGNOSTICSENGINE
290 Author
: Date
:
2001 AVALON (RM808U)
DTC P1520 Stop Light Switch Signal Malfunction
CIRCUIT DESCRIPTION
This signal is used to detect when the brakes have been applied. The STP signal voltage is the same as
the voltage supplied to the stop lights.
The STP signal is used mainly to control the fuel cut-off engine speed (The fuel cut-off engine speed is re-
duced slightly when the vehicle is braking.).
DTC No.DTC Detecting ConditionTrouble Area
P1520
Stop light switch does not turn off when repeating driving at 30
km or more 10 time or more after depressing brake (2 trip
detection logic)
Short in stop light switch signal circuit

Stop light switch

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.
1 Check operation of stop light.
CHECK:
Check if the stop lights go on and off normally when the brake pedal is operated and released.
NG Check and repair stop light circuit.
DI088-09

A02037
ON
ON
STP
Brake Pedal
DepressedBrake Pedal
Released
(+)
(-)
- DIAGNOSTICSENGINE
DI-135
291 Author
: Date
:
2001 AVALON (RM808U)
OK
2 Check STP signal.
When using TOYOTA hand-held tester:
PREPARATION:
(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.
CHECK:
Read the STP signal on the TOYOTA hand-held tester.
OK:
Brake PedalSTP Signal
DepressedON
ReleasedOFF
When not using TOYOTA hand-held tester:
PREPARATION:
Turn the ignition switch ON.
CHECK:
Check the voltage between terminal STP of the ECM connector
and body ground.
OK:
Brake PedalVoltage
Depressed7.5 - 14 V
ReleasedBelow 1.5 V
OK Check for intermittent problems
(See page DI-3).
NG
3 Check harness and connector between ECM and stop light switch
(See page IN-30).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN-30).

A11417
Battery FL
Main B
F6 F71 12
81
B Fusible
Link BlockEngine Room J/B
2G 2B E8B-RECM
BATT EFI No.1
II1 10
B-R DI-136
- DIAGNOSTICSENGINE
292 Author
: Date
:
2001 AVALON (RM808U)
DTC P1600 ECM BATT Malfunction
CIRCUIT DESCRIPTION
Battery positive voltage is supplied to terminal BATT of the ECM even when the ignition switch is OFF for
use by the DTC memory and air-fuel ratio adaptive control value memory, etc.
DTC No.DTC Detecting ConditionTrouble Area
P1600Open in back up power source circuit
Open in back up power source circuit

ECM
HINT:
If DTC P1600 appear, the ECM does not store another DTC.
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.
DI089-09

A02038
LOCK
BATT
(+)
(-)
A11423
Engine Room J/B
EFI No.1
Fuse
- DIAGNOSTICSENGINE
DI-137
293 Author
: Date
:
2001 AVALON (RM808U)
1 Check voltage between terminal BATT of ECM connector and body ground.
PREPARATION:
Remove the glove compartment (See page SF-82).
CHECK:
Measure the voltage between terminal BATT of the ECM con-
nector and body ground.
OK:
Voltage: 9 - 14 V
OK Check and replace ECM (See page IN-30).
NG
2 Check EFI No.1 fuse.
PREPARATION:
Remove the EFI No.1 fuse from the engine room J/B.
CHECK:
Check the continuity of the EFI No.1 fuse.
OK:
Continuity
NG Check for short in all harness and components
connected to EFI No.1 fuse.
OK
Check and repair harness or connector be-
tween battery and EFI No.1 fuse, and EFI No.1
fuse and ECM.

DI-138
- DIAGNOSTICSENGINE
294 Author
: Date
:
2001 AVALON (RM808U)
DTC P1656 OCV Circuit Malfunction (bank 1)
DTC P1663 OCV Circuit Malfunction (bank 2)
CIRCUIT DESCRIPTION
Refer to DTC P1349, P1354 on page DI-127.
DTC No.DTC Detecting ConditionTrouble Area
P1656
P1663Open or short in oil control valve circuit

Open or short in OCV circuit

OCV

ECM
WIRING DIAGRAM
Refer to DTC P1349, P1354 on page DI-127.
INSPECTION PROCEDURE
HINT:

If DTC P1656 dysplayed, check left bank OCV circuit.

If DTC P1663 dysplayed, check right bank OCV circuit.

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.
TOYOTA hand-held tester:
1 Check OCV circuit.
PREPARATION:
(a) Start the engine and warmed it up.
(b) Connect the TOYOTA hand-held tester and select the VVT from the ACTIVE TEST menu.
CHECK:
Check the engine speed when operate the OCV by the TOYOTA hand-held tester.
OK:
VVT system is OFF (OCV is OFF): Normal engine speed
VVT system is ON (OCV is ON): Rough idle or engine stalled
OK Check for intermittent problems
(See page DI-3).
NG
DI6TC-01

A06076A11891
- DIAGNOSTICSENGINE
DI-139
295 Author
: Date
:
2001 AVALON (RM808U)
2 Check operation of OCV.
PREPARATION:
(a) Start the engine and warmed it up.
(b) Disconnect the OCV connector.
(c) Apply battery positive voltage between terminals of the
OCV.
CHECK:
Check the engine speed.
OK:
Rough idle or engine stalled.
NG Replace OCV.
OK
3 Check voltage between terminals OCV+ and OCV- of ECM connector (See page
DI-127, step 3).
NG Check and replace ECM (See page IN-30).
OK
4 Check for open and short in harness and connector between OCV and ECM (See
page IN-30).
NG Repair or replace.
OK
Check for intermittent problems (See page
DI-3).

A06076A11891
DI-140
- DIAGNOSTICSENGINE
296 Author
: Date
:
2001 AVALON (RM808U)
OBD II scan tool (excluding TOYOTA hand-held tester):
1 Check operation of OCV.
PREPARATION:
(a) Start the engine and warmed it up.
(b) Disconnect the OCV connector.
(c) Apply battery positive voltage between terminals of the
OCV.
CHECK:
Check the engine speed.
OK:
Rough idle or engine stalled
NG Replace OCV.
OK
2 Check voltage between terminals OCV+ and OCV- of ECM connector (See page
DI-127, step 3).
NG Check and replace ECM (See page IN-30).
OK
3 Check for open and short in harness and connector between OCV and ECM (See
page IN-30).
NG Repair or replace.
OK
Check for intermittent problems (See page
DI-3).

- DIAGNOSTICSENGINE
DI-141
297 Author
: Date
:
2001 AVALON (RM808U)
DTC P1780 Park/Neutral Position Switch Malfunction
CIRCUIT DESCRIPTION
The park/neutral position switch go on when the shift lever is in the N or P shift position. When it goes on,
terminal NSW of the ECM is grounded to body ground via the starter relay, thus the terminal NSW voltage
becomes 0V. When the shift lever is in the D, 2, L or R position, the park/neutral position switch goes off,
so the voltage of ECM. Terminal NSW becomes battery voltage, the voltage of the ECM internal power
source. If the shift lever is moved from the N position to the D position, this signal is used for air-fuel ratio
correction and for idle speed control (estimated control), etc.
DTC No.DTC Detecting ConditionTrouble Area
P1780
When driving under conditions (a) and (b) for 30 sec. or more
the park/neutral position switch is ON (N position): (2 trip
dt ti l i)

Short in park/neutral position switch circuit
P k/ t l iti it hP1780detection logic)
(a) Vehicle speed: 40 km/h (25 mph) or more
(b) Engine speed: 1,500 - 4,000 rpm
Park/neutral position switch

ECM
HINT:
After confirming DTC P1780, use the TOYOTA hand-held tester to confirm the PNP switch signal from the
CURRENT DATA.
WIRING DIAGRAM
Refer to DTC P1780 on page DI-199.
INSPECTION PROCEDURE
Refer to DTC P1780 on page DI-199.
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.
DI08A-09