Toyota Celica 2005 Repair Manual page 1019

DI−818
Fail safe function:
If either of the solenoid valve circuits develops an open or short, the ECM turns the other solenoid valve ON
and OFF to shift to the gear positions shown in the table on the previous page. The ECM also turns the shift
solenoid valve ST OFF at the same time. If both solenoids malfunction, hydraulic control cannot be per-
formed electronically and must be done manually.
Manual shifting as shown in the table on the previous page must be done (In the case of a short circuit, the
ECM stops sending current to the short circuited solenoid).
MONITOR DESCRIPTION
The ECM commands gearshift by turning the shift solenoid valves "ON/OFF". When there is an open or short
circuit in any shift solenoid valve circuit, the ECM detects the problem and illuminates the MIL and stores
the DTC. And the ECM performs the fail−safe function and turns the other shift solenoid valves in good condi-
tion "ON/OFF" (In case of an open or short circuit, the ECM stops sending current to the circuit.).
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 these
DTCs are not present.
Range check (Low resistance)
Shift solenoid valve
Range check (High resistance)
Shift solenoid valve
TYPICAL MALFUNCTION THRESHOLDS
Detection criteria
Either of the following conditions is met: Range check (Low resistance) or (High resistance)
Range check (Low resistance)
Shift solenoid valve resistance
Range check (High resistance)
Shift solenoid valve resistance
2005 CELICA (RM1131U)
DIAGNOSTICS
P0753
P0758
P0753: Shift solenoid valve S1
P0758: Shift solenoid valve S2
Continuous
0.032 sec.
Immediate
None
Minimum
− AUTOMATIC TRANSAXLE (U341E)
Shift solenoid valve S1/Range check (Low resistance)
Shift solenoid valve S1/Range check (High resistance)
Shift solenoid valve S2/Range check (Low resistance)
Shift solenoid valve S2/Range check (High resistance)
Specification
See page DI−758
ON
OFF
100 kΩ or more
1018
Maximum
Threshold
8 Ω or less