2001 TOYOTA AVALON Service Repair Manual

DI-130
- DIAGNOSTICSENGINE
286 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
OBD II scan tool (excluding TOYOTA hand-held tester):
1 Check valve timing (See page EM-15).
NG Repair valve timing.
OK

A06076
OCV Connector(a)
(b)
A02397
OCV Signal Waveform
1 msec./Division5 V/
Division
GND
(A) (A) (A)
- DIAGNOSTICSENGINE
DI-131
287 Author
: Date
:
2001 AVALON (RM808U)
2 Check operation of OCV.
PREPARATION:
Start the engine.
CHECK:
(a) Check the engine speed when disconnecting the OCV
connector.
(b) Check the engine speed when applying battery positive
voltage between the terminals of the OCV.
RESULT:
ResultCheck (a)Check (b)
1Normal engine speedRough idle or engine stall
2Except 1
2 Go to step 4.
1
3 Check voltage between terminals OCV+ and OCV- of ECM connector.
Reference: INSPECTION USING OSCILLOSCOPE
Turn the ignition switch ON, check the waveform between termi-
nals OCV+ and OCV- of the ECM connector.
HINT:

The correct waveform is as shown.

The waveform frequency (A) is lengthened as the engine
speed becomes higher.
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

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.