engine TOYOTA AVALON 2001 Service Repair Manual

D07910
C9
O/D OFF
Indicator Light
15
7
G-O163G 3AG-O9
E8ECM
ODLP
2
3F Y-G2
3CY-R13
1B
ECU-IG
No. 2211
1GW
W-B3
1B
4
IG1 RELAY34
1CW-R
I15 Ignition Switch
24
AM1 IG1 W-L 7
IF1 W-L
5 2 AM1
1
5 B
1
2H
12G
B-L
1
F8 F101
ALTF6BFL MAINBattery
IJ W-B 7
7
4A
W-B
O34
*12*1
O3
3
*2G-O
12
E6ODMS
*1: Floor Shift*2: Column Shift1
*2 16
W
O/D Main
Switch IG
Driver Side J/B
Engine Room R/B No. 5
Engine
Room
J/B
A 8
II2
G-O
J9 J/ C 4BJ/B No. 4 J/B No. 3
1 DI-206
- DIAGNOSTICSAUTOMATIC TRANSAXLE
362 Author
: Date
:
2001 AVALON (RM808U)
O/D Main Switch & O/D OFF Indictor Light Circuit
CIRCUIT DESCRIPTION
The O/D main switch is a momentary type switch. When pressing the O/D OFF main switch, the O/D OFF
indicator light lights up and ECM prohibits shifting to O/D, and when pressing it again, the O/D OFF indicator
light goes off and ECM allows shifting to O/D. Turning the IG switch OFF will reset the O/D OFF indicator
light.
WIRING DIAGRAM
DI1KD-08

DI4DO-02
A00022
4-pulse
Combination
MeterECM 4-pulse
From
Speed SensorABS ECU DI-178
- DIAGNOSTICSAUTOMATIC TRANSAXLE
334 Author
: Date
:
2001 AVALON (RM808U)
CIRCUIT INSPECTION
DTC P0500 Vehicle Speed Sensor Malfunction
CIRCUIT DESCRIPTION
The speed sensor for ABS detects the wheel speed and sends the appropriate signals to the ABS ECU.
The ECU converts these signals in to a 4-pulse signal and outputs it to the combination meter.
After this signal is converted into a more precise rectangular waveform by the waveform shaping circuit in-
side the combination meter, it is then transmitted to the ECM. The ECM determines the vehicle speed based
on the frequency of these pulse signals.
DTC No.DTC Detecting ConditionTrouble Area
P0500
Satisfying all of the following conditions, 2 sec. (Intake air tem-
perature: -10 °C or more) or 8 sec. (Intake air temperature:
less than -10 °C) elapsed.
(c) After 2 sec. (the engine coolant temperature: 20 °C or
more) or 30 sec. (the engine coolant temperature: less than
20 °C) with the park/neutral position switch set to P, N posi-
tion.
(d) No abnormality of the throttle position sensor is detected.
(e) After 0.5 sec. or more with the ignition switch turned ON.
(f) No vehicle speed is signal to ECM.
(g) The engine rpm is equal to the speed sensor rpm or more
when the throttle opening angle is as shown below.
1. The throttle opening angle is less than 13° and the engine
rpm is 2,350 or more.
2. The throttle opening angle is less than 21° and the engine
rpm is 2,680 or more.
3. The throttle opening angle is less than 30° and the engine
rpm is 2,835 or more.
4. The throttle opening angle is less than 30° and the engine
rpm is 3,145 or more.

Open or short in vehicle speed sensor circuit

ABS speed sensor

Combination meter

ECM

ABS ECU

Automatic transaxle (clutch, brake or gear etc.)
Clutch or brake slips or gear is broken (2-trip detection logic)

DI-192
- DIAGNOSTICSAUTOMATIC TRANSAXLE
348 Author
: Date
:
2001 AVALON (RM808U)
DTC P1520 Stop Light Switch Signal Malfunction
CIRCUIT DESCRIPTION
The purpose of this circuit is to prevent the engine from stalling, while driving in lock-up condition, when
brakes are suddenly applied.
When the brake pedal is operated, this switch sends a signal to ECM. Then the ECM cancels operation of
the lock-up clutch while braking is in progress.
DTC No.DTC Detecting ConditionTrouble Area
P1520No stop light switch signal to ECM during driving.
(2-trip detection logic)
Open or short in stop light switch circuit

Stop light switch

ECM
WIRING DIAGRAM
See page DI-134.
INSPECTION PROCEDURE
See page DI-134.
DI02O-06

Q04869
NC2 Revolution Sensor
D07907
E4
E4 1O1 2
G R
Direct Clutch
Speed Sensor24
NC2+
ECM
NC2
-
23
- DIAGNOSTICSAUTOMATIC TRANSAXLE
DI-193
349 Author
: Date
:
2001 AVALON (RM808U)
DTC P1705 NC2 Revolution Sensor Circuit Malfunction
(Direct Clutch Speed Sensor)
CIRCUIT DESCRIPTION
This sensor detects the rotation speed of the direct clutch drum.
By comparing the direct clutch speed signal with the vehicle
speed sensor signal, the ECM detects the shift timing of the
gears and appropriately controls the engine torque and hydrau-
lic pressure in response to various conditions, thus performing
smooth gear shifting.
DTC No.DTC Detecting ConditionTrouble Area
P1705
The ECM detects conditions (a), (b), (c), (d), (e) and (f) conti-
nuity for 4 secs. or more.
(2-trip detection logic)
(a) Gear change not being performed
(b) Gear position: 1st, 2nd 3rd or O/D
(c) T/M input shaft rpm: 300 rpm or less
(d) T/M output shaft rpm: 1,000 rpm or more
(e) Park/neutral position switch: OFF
(f) Shift solenoid valves No. 1, No. 2, SL and vehicle speed
sensor are in normal operation.

Open or short in direct clutch speed sensor circuit

Direct clutch speed sensor

ECM
WIRING DIAGRAM
DI02P-07

AT5608
Accumulator Control Pressure
High
Electric Current (A) 0
1
D00060
(*) Duty Ratio
The duty ratio is the ratio of the period of continuity in one cycle.
For example, if A is the period of continuity in one cycle, and B is the period of non-continuity, then
D00062
Reference
Waveform between terminals SLN
+
and SLN- when engine is idling.
5 V / Div.
GND Waveform between terminals SLN
+
and SLN- during shift change.
5 V / Div.
GND
1 msec. / Div.1 msec. / Div.
- DIAGNOSTICSAUTOMATIC TRANSAXLE
DI-195
351 Author
: Date
:
2001 AVALON (RM808U)
DTC P1765Linear Solenoid for Accumulator Pressure Control
Circuit Malfunction (Shift Solenoid Valve SLN)
CIRCUIT DESCRIPTION
The shift solenoid valve SLN controls the hydraulic pressure
acting on the accumulator control valve when gears are shifted
and performs smooth gear shifting.
The ECM determines optimum operating pressure according to
the signals from the throttle position sensor, vehicle speed sen-
sor and direct clutch speed sensor and controls the volume of
current flow to the solenoid valve.
The amount of current to the solenoid is controlled by the (*)
duty ratio of ECM output signals, causing a momentary change
to the hydraulic pressure acting on the clutches during gear
shifting.
When the duty ratio is high, the hydraulic pressure acting on the
clutches is low.
DTC No.DTC Detecting ConditionTrouble Area
P1765
After the engine is warmed up, the current flows to the shift
solenoid valve SLN for 1 sec or more under condition (a) or
(b):
(a) Engine speed: 500 rpm or more
(b) Park/neutral position switch: ON (P or N position)

Open or short in shift solenoid valve SLN circuit

Shift solenoid valve SLN

ECM
DI02Q-07

- DIAGNOSTICSAUTOMATIC TRANSAXLE
DI-199
355 Author
: Date
:
2001 AVALON (RM808U)
DTC P1780 Park/Neutral Position Switch Malfunction
CIRCUIT DESCRIPTION
The park/neutral position switch detects the shift lever position and sends signals to the ECM.
The ECM receives signals (NSW, R, 2 and L) from the park/neutral position switch. When the signal is not
sent to the ECM from the park/neutral position switch, the ECM judges that the shift lever is in D position.
DTC No.DTC Detection ConditionTrouble Area
P1780
When driving under conditions (a) and (b) for 30 seconds or
more, the park/neutral position switch is ON (N position).
(2-trip detection logic)
(a) Vehicle speed: 70 km/h (44 mph) or more
(b) Engine speed: 1,500 - 2,500 rpm

Short in park/neutral position switch circuit

Park/neutral position switch

ECM
DI6K8-01

D07909
J5 J/C
A
A77
3A 3GW-B
P1
Park/Neutral
Position switch
W-B
2RL
2L
LLR-B
8
G-Y
3
Y
41
II1
2
II2
II2R-B
G-Y
Y18
3C
3C
3B
7
3C 3C
3D
3D 3C
GR *2
R-L
W-B20
20
15 15
FUSIBLE LINK
BLOCK
IG8
1D
1C
1B 1
1
3C9
Combination Meter
R2L
R-B G-Y
Y 25 6
16
1718 16 17
3F 3F 3G
3D
3A 3D18
16
17R-B
G-Y
Y
R-L
*1
R-L
*2
GR
*22
4D 4C11DIODE D6
3
2
1
GR
*2
ECU-ACC
GAUGE No. 2
2
410
1C
1G
1C1
4 1
3
F10
F8
F7
F6 11
1
1B-L
B2G
2G2H
2C 11
27AM2
BFL MAINBatteryB
5
1AM1
25
W-RW-L7
IF1
W-R W-L W-R W-G
4 3
IG1ACC ST2AM2
8 B-W R-L2020
E7 18
7
6R-B
G-Y
YE6
E6
E6R
2
LECM
NSW
I15
Ignition Switch
7
2 8
14
13
IG1 RELAY R-L
W
4 W-BJ/B No. 3
21
II2
II2
II2
J/B No. 3
J/B No. 3
J/B No. 4II1
Driver Side J/B
ALTEngine Room J/B Engine Room R/B No. 5
IF1 W-B*2
*1: Floor Shift
*2: Column ShiftAM1 DI-200
- DIAGNOSTICSAUTOMATIC TRANSAXLE
356 Author
: Date
:
2001 AVALON (RM808U)
WIRING DIAGRAM

DI02E-08
FI0534
F07887DLC3
TOYOTA hand-held tester
DI-160
- DIAGNOSTICSAUTOMATIC TRANSAXLE
316 Author
: Date
:
2001 AVALON (RM808U)
PRE-CHECK
1. DIAGNOSIS SYSTEM
(a) Description

When troubleshooting OBD II vehicles, the only dif-
ference from the usual troubleshooting procedure
is that you connect to the vehicle an OBD II scan
tool complying with SAE J1987 or TOYOTA hand-
held tester, and read off various data output from
the vehicle's ECM.

OBD II regulations require that the vehicle's on-
board computer lights up the Malfunction Indicator
Lamp (MIL) on the instrument panel when the com-
puter detects a malfunction in the computer itself or
in drive system components which affect vehicle
emissions. In addition to the MIL lighting up when
a malfunction is detected, the applicable DTCs pre-
scribed by SAE J2012 are recorded in the ECM
memory (See page DI-14).
If the malfunction only occurs in 3-trip, the MIL goes
off but the DTCs remain recorded in the ECM
memory.

To check the DTCs, connect an OBD II scan tool or
TOYOTA hand-held tester to DLC3 on the vehicle.
The OBD II scan tool or TOYOTA hand-held tester
also enables you to erase the DTCs and check
freeze frame data and various forms of engine data
(For instruction book).

DTCs include SAE controlled codes and Manufac-
turer controlled codes.
SAE controlled codes must be set as prescribed by
the SAE, while Manufacturer controlled codes can
be set freely by the manufacturer within the pre-
scribed limits (See DTC chart on page ).

FI0534
F07887
TOYOTA hand-held tester
DLC3
DI-162
- DIAGNOSTICSAUTOMATIC TRANSAXLE
318 Author
: Date
:
2001 AVALON (RM808U)
2. INSPECT DIAGNOSIS (NORMAL MODE)
(a) Check the MIL.
(1) The MIL comes on when the ignition switch is turned
ON and the engine is not running.
HINT:
If the MIL does not light up, troubleshoot the combination meter
(See page BE-2).
(2) When the engine is started, the MIL should go off.
If the lamp remains on, the diagnosis system has
detected a malfunction or abnormality in the sys-
tem.
(b) Check the DTC.
NOTICE:
TOYOTA hand-held tester only:
When the diagnostic system is switched from normal mode
to check mode, it erases all DTCs and freeze frame data re-
corded in normal mode. So before switching modes, al-
ways check the DTCs and freeze frame data, and note them
down.
(1) Prepare an OBD II scan tool (complying with SAE
J1978) or TOYOTA hand-held tester.
(2) Connect the OBD II scan tool or TOYOTA hand-
held tester to DLC3 at the lower of the instrument
panel.
(3) Turn the ignition switch ON and turn the OBD II scan
tool or TOYOTA hand-held tester switch ON.
(4) Use the OBD II scan tool or TOYOTA hand-held
tester to check the DTCs and freeze frame data and
note them down (For operating instructions, see the
OBD II scan tool's instruction book).
(5) See page DI-172 to confirm the details of the DTCs.
NOTICE:
When simulating symptoms with an OBD II scan tool (ex-
cluding TOYOTA hand-held tester) to check the DTCs, use
normal mode. For codes on the DTCs chart subject to
º2-trip detection logicº, turn the ignition switch OFF after
the symptoms have been simulated the 1st time. Then re-
peat the simulation process again. When the program has
DTCs they are recorded in the ECM.

F07887
TOYOTA hand-held tester
DLC3
BR3904
0.13 sec. 0.13 sec.
ON
OFF
- DIAGNOSTICSAUTOMATIC TRANSAXLE
DI-163
319 Author
: Date
:
2001 AVALON (RM808U)
3. INSPECT DIAGNOSIS (CHECK MODE)
HINT:
TOYOTA hand- held tester only: Compared to the normal
mode, the check mode has high sensing ability to detect mal-
functions. Furthermore, the same diagnostic items which are
detected in Normal mode can also be detected in Check mode.
(a) Check the DTC.
(1) Check the initial conditions.

Battery positive voltage 11 V or more

Throttle valve fully closed

Transaxle in P position

Air conditioning switched OFF
(2) Turn the ignition switch OFF
(3) Prepare a TOYOTA hand-held tester
(4) Connect the TOYOTA hand-held tester to DLC3 at
the lower of the instrument panel.
(5) Turn the ignition switch ON and switch the TOYOTA
hand-held tester ON.
(6) Switch the TOYOTA hand-held tester from Normal
mode to Check mode (Check that the MIL flashes).
(7) Start the engine (MIL goes out after the engine
starts).
(8) Simulate the conditions of the malfunction de-
scribed by the customer.
NOTICE:
Leave the ignition switch ON until you have checked the
DTCs, etc..
(9) After simulating the malfunction conditions, use the
TOYOTA hand-held tester diagnosis selector to
check the DTCs and freeze frame data, etc.
HINT:
Take care not to turn the ignition switch OFF, as turning it off
switches the diagnosis system from Check mode to Normal
mode, so all DTCs, etc. are erased.
(10) After checking the DTC, inspect the applicable cir-
cuit.