Toyota Celica 2005 Repair Manual page 1022

DTC P0785
CIRCUIT DESCRIPTION
Shift solenoid valve ST is switched ON−OFF by a signal from ECM so that let in or out timing of 2nd brake
is adjusted by operating orifice control valve. Therefore, ST solenoid operates when letting in or out reverse
clutch.
If it is broken, the shift shock becomes big.
DTC No.
ECM memorizes DTC P0785 if (a) or (b) condition below is
detected once or more. (1−trip detection logic)
(a) Solenoid resistance is 8 Ω or lower (short circuit) when
P0785
solenoid energized.
(b) Solenoid resistance is 100 kΩ or higher (open circuit) when
solenoid is not energized.
MONITOR DESCRIPTION
The ECM reduces the gear shift shock when shifting from the N position to the D position and from 3rd gear
to 4th gear by regulating the hydraulic line pressure. To regulate the pressure, the ECM controls shift−sole-
noid ST with a duty−cycle signal that adjusts the line−pressure.
If the ECM detects an open or short in the shift−solenoid ST circuit, it will illuminate the MIL and store the
DTC.
MONITOR STRATEGY
Related DTCs
Required sensors/Components
Frequency of operation
Duration
MIL operation
Sequence of operation
TYPICAL ENABLING CONDITIONS
Item
The monitor will run whenever this DTC is
not present.
Range check (Low resistance)
Shift solenoid valve
Range check (High resistance)
Shift solenoid valve
2005 CELICA (RM1131U)
DIAGNOSTICS
Shift/Timing Solenoid
(Shift Solenoid Valve ST)
DTC Detecting Condition
P0785
Shift solenoid valve ST
Continuous
0.032 sec.
Immediate
None
Minimum
− AUTOMATIC TRANSAXLE (U341E)
S Open or short in shift solenoid valve ST circuit
S Shift solenoid valve ST
S ECM
Shift solenoid valve ST/Range check (Low resistance)
Shift solenoid valve ST/Range check (High resistance)
Specification
See page DI−758
ON
OFF
1021
Trouble Area
Maximum
DI−821
DIAJF−03