Dtc P0973 Shift Solenoid A Control Circuit Low (Shift Solenoid Valve S1)
DESCRIPTION
MONITOR DESCRIPTION
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
COMPONENT OPERATING RANGE
WIRING DIAGRAM
INSPECTION PROCEDURE
INSPECT TRANSMISSION WIRE (S1)
CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)
INSPECT SHIFT SOLENOID VALVE S1
DTC P0973 Shift Solenoid "A" Control Circuit Low (Shift Solenoid Valve S1) |
DTC P0974 Shift Solenoid "A" Control Circuit High (Shift Solenoid Valve S1) |
DESCRIPTION
Shifting from 1st to 4th is performed in combination with "ON" and "OFF" of the shift solenoid valve S1 and S2 controlled by ECM. If an open or short circuit occurs in either of the solenoid valves, the ECM controls the remaining normal solenoid valve to allow the vehicle to be operated smoothly (Fail safe function).DTC No.
| DTC Detection Condition
| Trouble Area
|
P0973
| ECM detects short in solenoid valve S1 circuit 2 times when solenoid valve S1 is operated (1-trip detection logic)
| - Short in shift solenoid valve S1 circuit
- Shift solenoid valve S1
- ECM
|
P0974
| ECM detects open in solenoid valve S1 circuit 2 times when solenoid valve S1 is not operated (1-trip detection logic)
| - Open in shift solenoid valve S1 circuit
- Shift solenoid valve S1
- ECM
|
MONITOR DESCRIPTION
The ECM commands gear shifts 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 condition "ON/OFF" (In case of an open or short circuit, the ECM stops sending current to the circuit.) (COROLLA_ZRE142 RM000000O8L0N1X.html).
MONITOR STRATEGY
Related DTCs
| P0973: Shift solenoid valve S1/Range check (Low resistance)
P0974: Shift solenoid valve S1/Range check (High resistance)
|
Required sensors/Components
| Shift solenoid valve S1
|
Frequency of operation
| Continuous
|
Duration
| 0.128 seconds or more
|
MIL operation
| Immediate
|
Sequence of operation
| None
|
TYPICAL ENABLING CONDITIONS
P0973: 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
|
P0974: 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
|
TYPICAL MALFUNCTION THRESHOLDS
P0973: Range check (Low resistance)Solenoid terminal voltage level
| Low
|
P0974: Range check (High resistance)Solenoid terminal voltage level
| High
|
COMPONENT OPERATING RANGE
Shift solenoid valve S1 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 (S1) |
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
|
5 - 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
|
B31-56 (S1) - Body ground
| 20°C (68°F)
| 11 to 15 Ω
|
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| 3.INSPECT SHIFT SOLENOID VALVE S1 |
Remove the shift solenoid valve S1.
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
Tester Connection
| Condition
| Specified Condition
|
Solenoid Connector (S1) - Solenoid Body (S1)
| 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.
