Toyota AVENSIS 2000 Supplement Manual page 159

DI–28
DTC P0753,P0758
CIRCUIT DESCRIPTION
Shifting from 1st to O/D is performed in combination with ON and OFF of the No. 1 and No. 2 solenoid valves
controlled by Engine and ECT ECU. If an open or short circuit occurs in either of the solenoid valves, the
Engine and ECT ECU controls the remaining normal solenoid valve to allow the vehicle to be operated
smoothly (Fail safe function).
NORMAL
Position
Solenoid valve
No.1 No.2
ON
ON
D
OFF
OFF
ON
2
ON
OFF
ON
L
ON
X: Malfunctions
HINT:
Check the No. 1 solenoid valve when DTC P0753/62 is output and check the No. 2 solenoid valve when
DTC P0758/63 is output.
DTC No.
The Engine and ECT ECU checks for an open or short circuit
in the No. 1 or No. 2 solenoid valve circuit when it changes.
The Engine and ECT ECU records DTC P0753/62 or
P0758/63 if condition (a) or (b) is detected once, but it does not
blink the O/D OFF indicator light.
After Engine and ECT ECU detects condition (a) or (b) continu-
ously 8 times or more in one–trip, it causes the O/D OFF indi-
P0753
cator light to light up until condition (a) or (b) disappears.
P0758
After that, if the Engine and ECT ECU detects condition (a) or
(b) once, it starts lighting up O/D OFF indicator light again.
(a) Solenoid resistance is 8 Ω or less (short circuit) when the
solenoid is energized.
(b) Solenoid resistance is 100 kΩ or more (open circuit) when
the solenoid is not energized.
Fail safe function:
If either of the solenoid valve circuits develops an open or short, the Engine and ECT ECU turns the other
solenoid valve ON and OFF to shift to the gear positions shown in the table above. The Engine and ECT
ECU also turns the ST solenoid valve OFF at the same time. If both solenoids malfunction, hydraulic control
cannot be performed electronically and must be done manually.
Manual shifting as shown in the above table must be done (In the case of a short circuit, the Engine and ECT
ECU stops sending current to the short circuited solenoid).
AVENSIS/CORONA SUP (RM781E)
DIAGNOSTICS
SHIFT SOLENOID NO.1
MALFUNCTIONING
Solenoid valve
Gear
No.1
OFF 1st X
ON 2nd X
ON 3rd X
OFF O/D X
OFF 1st X
ON 2nd X
ON 3rd X
OFF 1st X
ON 2nd X
DTC Detecting Condition
– AUTOMATIC TRANSAXLE (A246E)
Shift Solenoid A/B Electrical Malfunc-
tion (No. 1/No. 2 Solenoid Valve)
SHIFT SOLENOID NO.2
MALFUNCTIONING
Solenoid valve
Gear
No.2 No.1
ON 3rd ON
ON 3rd OFF
ON 3rd OFF
OFF O/D OFF
ON 3rd ON
ON 3rd OFF
ON 3rd OFF
OFF 1st ON
ON 2nd ON
S Open or short in No. 1/No. 2 solenoid valve circuit
S No. 1/No. 2 solenoid valve
S Engine and ECT ECU
BOTH SOLENOID
MALFUNCTIONING
Gear when shift selector is
Gear
manually operated
No.2
X 1st
X O/D
X O/D
X O/D
X 1st
X O/D
X O/D
X 1st
X 1st
Trouble Area
DI1FW–06
O/D
O/D
O/D
O/D
3rd
3rd
3rd
1st
1st