2001 TOYOTA AVALON Service Repair Manual

Q30002
(-)(+)
(-)(+)
- DIAGNOSTICSAUTOMATIC TRANSAXLE
DI-181
337 Author
: Date
:
2001 AVALON (RM808U)
DTC P0750, P0755 Shift Solenoid A/B Malfunction
(Shift Solenoid Valve No.1/No.2)
SYSTEM DESCRIPTION
The ECM uses signals from the vehicle speed sensor and direct clutch speed sensor to detect the actual
gear position (1st, 2nd, 3rd or O/D gear).
Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical
trouble of the shift solenoid valves, valve body or automatic transaxle (clutch, brake or gear etc.).
DTC No.DTC Detecting ConditionTrouble Area
P0750
P0755During normal driving, the gear required by the ECM does not
match the actual gear
(2-trip detection logic)
Shift solenoid valve No.1/No.2 is stuck open or closed

Valve body is blocked up or stuck

Automatic transaxle (clutch, brake or gear etc.)
HINT:
Check the shift solenoid valve No.1 when DTC P0750 is output and check the shift solenoid valve No.2 when
DTC P0755 is output.
INSPECTION PROCEDURE
1 Check shift solenoid valve No.1 or No.2 operation.
PREPARATION:
(a) Remove the oil pan.
(b) Remove the shift solenoid valve No.1 or No.2.
CHECK:
(a) Applying 490 kPa (5 kgf/cm2, 71 psi) of compressed air,
check that the solenoid valve does not leak air.
(b) When battery positive voltage is supplied to the shift sole-
noid valve, check that the valve opens.
OK:
(a) Solenoid valve does not leak air.
(b) Solenoid valve opens.
NG Replace the shift solenoid valve No.1 or No.2.
OK
DI02K-08

DI-182
- DIAGNOSTICSAUTOMATIC TRANSAXLE
338 Author
: Date
:
2001 AVALON (RM808U)
2 Check the valve body (See page DI-175).
NG Repair or replace the valve body.
OK
Repair the transaxle.

PositionNORMALSHIFT SOLENOID NO.1
MALFUNCTIONING
Solenoid valve
No.1GearSHIFT SOLENOID NO.2
MALFUNCTIONINGBOTH SOLENOIDS MAL-
FUNCTIONINGGear when shift selector is
manually operated
D
2
L
ON
1st 2nd
3rd
O/D
1st 2nd
3rd
1st
2nd1st
X: MalfunctionsNo.2
ONNo.1 No.2
No.1 No.2 Solenoid valveSolenoid valve
GearGear
OFF
OFF
ON ON
OFF
ON
ONOFF
OFF
OFF
OFFON
ON
ON
ON
ONX
3rd
X
X
X
X
X
X
X
XON
ON
ON
ON
ON
ON
ON3rd
3rd
3rd
3rd
3rd O/D
1st
2ndON
ON
ON
ON OFF
OFFOFF
OFF
OFF
OFF
OFFX
X
X
X
X
X
X
X
X1st
O/D
O/D
O/D
O/D
O/D
1st
1stO/D
O/D
O/D
O/D
O/D
O/D
O/D
1st
1st
- DIAGNOSTICSAUTOMATIC TRANSAXLE
DI-183
339 Author
: Date
:
2001 AVALON (RM808U)
DTC P0753, P0758 Shift Solenoid A/B Electrical Malfunc-
tion (Shift Solenoid Valve No.1/No.2)
CIRCUIT DESCRIPTION
Shifting from 1st to O/D is performed in combination with ON and OFF of the shift solenoid valves No.1 and
No.2 controlled by ECM. If an open or short circuit occurs in either of the shift solenoid valves, the ECM con-
trols the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly (Fail safe func-
tion).
Fail safe function:
If either of the shift solenoid valve circuits develops an open or short, the ECM turns the other shift solenoid
ON and OFF to shift to the gear positions shown in the table below. The ECM also turns the shift solenoid
valve SL OFF at the same time. If both solenoids are malfunctioning, hydraulic control cannot be performed
electronically and must be done manually.
Manual shifting as shown in the following table must be done (In the case of a short circuit, the ECM stops
sending current to the short circuited solenoid).
HINT:
Check the shift solenoid valve No.1 when DTC P0753 is output and check the shift solenoid valve No.2 when
DTC P0758 is output.
DTC No.DTC Detecting ConditionTrouble Area
P0753
P0758
The ECM checks for an open or short circuit in the shift sole-
noid valve No.1 and/or No.2 circuit when it changes.
The ECM records DTC P0753 or P0758 if condition (a) or (b) is
detected once, but it does not light up MIL.
After ECM detects condition (a) or (b) continuously 8 times or
more in a trip and the MIL lights up.
(a) When the solenoid is energized, the solenoid resistance
is 8 W or less and is counted.
(b) When the solenoid is not energized, the solenoid resistance
is 100 kW or more and is counted.

Open or short in shift solenoid valve No.1/No.2 circuit

Shift solenoid valve No.1/No.2

ECM
DI02L-08

D07908
Transaxle
Shift Solenoid Valve No.1
3
6 S1
Shift Solenoid
Valve No.2S2G-YE47
1
E6ECM
S1
S2 P
G-Y
B
BB J8
J/C
From Cruise Control ECU DI-184
- DIAGNOSTICSAUTOMATIC TRANSAXLE
340 Author
: Date
:
2001 AVALON (RM808U)
WIRING DIAGRAM

D06557
S1
S2
D06558Q02283D07489
S1S2
S2 S1
- DIAGNOSTICSAUTOMATIC TRANSAXLE
DI-185
341 Author
: Date
:
2001 AVALON (RM808U)
INSPECTION PROCEDURE
1 Measure resistance between terminal S1 or S2 of ECM and body ground.
PREPARATION:
(a) Remove the glove compartment (See page BO-90).
(b) Disconnect the connector from ECM.
CHECK:
Measure resistance between terminal S1 or S2 of ECM and
body ground.
OK:
Resistance: 11 - 15 W
OK Check and replace the ECM (See page IN-30).
NG
2 Measure resistance of harness and connector between ECM and automatic
transaxle solenoid connector.
PREPARATION:
Disconnect the solenoid connector from the automatic trans-
axle.
CHECK:
Measure resistance of the harness and connector between ter-
minal S1 or S2 of ECM and terminal S1 or S2 of solenoid con-
nector.
OK:
Resistance: 0 W
NG Repair or replace the harness or connector.
OK

D04448
(+)
(-)
DI-186
- DIAGNOSTICSAUTOMATIC TRANSAXLE
342 Author
: Date
:
2001 AVALON (RM808U)
3 Check shift solenoid valve No.1 or No.2.
PREPARATION:
(a) Jack up the vehicle.
(b) Remove the oil pan.
(c) Disconnect the solenoid connector.
(d) Remove the shift solenoid valve No.1 or No.2.
CHECK:
(a) Measure resistance between solenoid connector and
body ground.
(b) Connect the positive
lead to terminal of solenoid con-
nector, negative  lead to solenoid body.
OK:
(a) Resistance: 11 - 15 W
(b) The solenoid makes an operating noise.
NG Replace the solenoid valve.
OK
Repair or replace the solenoid wire.

Q04874
Controlled
Pressure
Drain Controlled
Pressure Line
Pressure
Q08040D02461
(+)
(+)
(-) (-)
- DIAGNOSTICSAUTOMATIC TRANSAXLE
DI-187
343 Author
: Date
:
2001 AVALON (RM808U)
DTC P0770 Shift Solenoid E Malfunction
(Shift Solenoid Valve SL)
SYSTEM DESCRIPTION
The ECM uses the signals from the throttle position sensor, air-
flow meter and crankshaft position sensor to monitor the en-
gagement condition of the lock-up clutch.
Then the ECM compares the engagement condition of the
lock-up clutch with the lock-up schedule in the ECM memory
to detect mechanical trouble of the shift solenoid valve SL,
valve body, torque converter clutch or automatic transaxle
(clutch, brake or gear etc.).
DTC No.DTC Detecting ConditionTrouble Area
P0770

Lock-up does not occur when driving in the lock-up range
(normal driving at 80 km/h [50 mph]), or lock-up remains ON
in the lock-up OFF range.
(2-trip detection logic)

When lock-up is ON, clutch or brake slips or gear is broken.
Shift solenoid valve SL is stuck open or closed

Valve body blocked up or stuck

Lock-up clutch

Automatic transaxle (clutch, brake or gear etc.)
INSPECTION PROCEDURE
1 Check solenoid valve SL operation.
PREPARATION:
(a) Remove the oil pan.
(b) Remove the shift solenoid valve SL.
CHECK:
(a) Applying 490 kPa (5 kgf/cm2, 71 psi) of compressed air,
check that the solenoid valve does not leak air.
(b) When battery positive voltage is supplied to the shift sole-
noid valve, check that the solenoid valve opens.
OK:
(a) Solenoid valve does not leak air.
(b) Solenoid valve opens.
NG Replace the solenoid valve SL.
OK
DI02M-08

DI-188
- DIAGNOSTICSAUTOMATIC TRANSAXLE
344 Author
: Date
:
2001 AVALON (RM808U)
2 Check valve body (See page DI-175).
NG Repair or replace the valve body.
OK
3 Check the torque converter clutch (See page AX-43).
NG Replace the torque converter clutch.
OK
Repair the transaxle (See page AX-33).