Dtc P0787 Shift / Timing Solenoid Low (Shift Solenoid Valve St)
DESCRIPTION
MONITOR DESCRIPTION
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
COMPONENT OPERATING RANGE
WIRING DIAGRAM
INSPECTION PROCEDURE
INSPECT TRANSMISSION WIRE (ST)
CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)
INSPECT SHIFT SOLENOID VALVE ST
DTC P0787 Shift / Timing Solenoid Low (Shift Solenoid Valve ST) |
DTC P0788 Shift / Timing Solenoid High (Shift Solenoid Valve ST) |
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, shift solenoid valve ST operates when letting in or out reverse clutch.If the shift solenoid valve ST is broken, the shift shock becomes big.DTC No.
| DTC Detection Condition
| Trouble Area
|
P0787
| ECM detects short in solenoid valve ST circuit 2 times when solenoid valve ST is operated (1-trip detection logic)
| - Short in shift solenoid valve ST circuit
- Shift solenoid valve ST
- ECM
|
P0788
| ECM detects open in solenoid valve ST circuit 2 times when solenoid valve ST is not operated (1-trip detection logic)
| - Open in shift solenoid valve ST circuit
- Shift solenoid valve ST
- ECM
|
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 the MIL comes on. Illuminating the MIL, the ECM performs the fail-safe and turns the other shift solenoid valves in good condition "ON/OFF" (In case of an open or short circuit, the ECM stops sending current to the circuit.).
MONITOR STRATEGY
Related DTCs
| P0787: Shift timing solenoid/Range check (Low resistance)
P0788: Shift timing solenoid/Range check (High resistance)
|
Required sensors/Components
| Shift solenoid valve ST
|
Frequency of operation
| Continuous
|
Duration
| 0.128 seconds
|
MIL operation
| Immediate
|
Sequence of operation
| None
|
TYPICAL ENABLING CONDITIONS
P0787: Range check (Low resistance)The monitor runs whenever the following DTCs are not present
| None
|
Solenoid
| ON
|
Time after solenoid OFF to ON
| More than 0.008 seconds
|
Battery voltage
| 8 V or more
|
Ignition switch
| ON
|
Starter
| OFF
|
P0788: Range check (High resistance)The monitor runs whenever the following DTCs are not present
| None
|
Solenoid
| OFF
|
Time after solenoid ON to OFF
| More than 0.008 seconds
|
Battery voltage
| 8 V or more
|
Ignition switch
| ON
|
Starter
| OFF
|
TYPICAL MALFUNCTION THRESHOLDS
P0787: Range check (Low resistance)Solenoid terminal voltage level
| Low
|
P0788: Range check (High resistance)Solenoid terminal voltage level
| High
|
COMPONENT OPERATING RANGE
Shift solenoid valve ST resistance
| 11 to 15 Ω at 20°C (68°F)
|
WIRING DIAGRAM
INSPECTION PROCEDURE
- NOTICE:
- Perform the universal trip to clear permanent DTCs (COROLLA_ZRE142 RM000000W770S5X.html).
| 1.INSPECT TRANSMISSION WIRE (ST) |
Disconnect the transmission wire connector from the transaxle.
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
Tester Connection
| Condition
| Specified Condition
|
2 - Body ground
| 20°C (68°F)
| 11 to 15 Ω
|
| 2.CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM) |
Connect the transmission wire connector to the transaxle.
Disconnect the ECM connectors.
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
Tester Connection
| Condition
| Specified Condition
|
B31-59 (ST) - Body ground
| 20°C (68°F)
| 11 to 15 Ω
|
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| 3.INSPECT SHIFT SOLENOID VALVE ST |
Remove the shift solenoid valve ST.
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
Tester Connection
| Condition
| Specified Condition
|
Solenoid Connector (ST) - Solenoid Body (ST)
| 20°C (68°F)
| 11 to 15 Ω
|
Connect the positive (+) lead to the terminal of the solenoid connector, and the negative (-) lead to the solenoid body.
- OK:
- The solenoid makes an operating sound.
