DTC Advanced Diagnostics: P0756
DTC P0756 : Shift Solenoid Valve B Stuck OFF
General Description
Shift solenoid valve B is installed on the valve body assembly. It is controlled by the ON/OFF signal from the transmission control module (TCM) to apply line pressure to the two-way clutch actuator valve. The two-way clutch is operated by driving the two-way clutch actuator valve with shift solenoid valves A, B, and D and clutch pressure control solenoid valve B. The two-way clutch actuator valve stroke sensor which measures the stroke position of the two-way clutch actuator valve is structured by two systems as the sensor characteristics are shown as in the figure. When the stroke value of the two-way clutch actuator valve stroke sensor is approximately 4.7 mm (0.19 in) or more, the two-way clutch is in reverse position, and when it is approximately -4.8 mm (-0.19 in) or less, it is in forward position. For detecting the malfunction, the TCM uses the values of the two-way clutch actuator valve stroke sensor and transmission fluid pressure switch B when the two-way clutch is switch controlled to the reverse position. If the two-way clutch actuator valve stroke sensor value is in abnormal range and transmission fluid pressure switch B is ON for a specified time when the two-way clutch is switch controlled to the reverse position, the TCM detects a shift solenoid valve B stuck off failure and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 1.5 seconds or more |
| DTC Type | Two drive cycles, MIL off, shift position indicator blinks |
Enable Conditions
| Condition | Minimum | Maximum | |
|---|---|---|---|
| Engine speed [Engine Speed] | 500 rpm | - | |
| 12 volt battery voltage [Battery Voltage] | 10 V | - | |
| Clutch C3 command pressure | 1, 050 kPa (10.7 kgf/cm 2, 152.3 psi) | - | |
| Control command to shift solenoid valve A | ON | ||
| Control command to shift solenoid valve B | ON | ||
| Control command to shift solenoid valve D | OFF | ||
| Other | Two-way clutch is in forward position when two-way clutch is started to switch control to reverse position (two-way clutch actuator valve stroke sensor value is -4.8 mm (-0.19 in) or less) | ||
[ ]: HDS Parameter
Malfunction Threshold
The two-way clutch actuator valve stroke sensor value is less than specified value and transmission fluid pressure switch B is ON for at least 1.5 seconds when the two-way clutch is switch controlled to the reverse position.
Possible Cause
- Valve body assembly failure (shift solenoid valve B stuck off)
Confirmation Procedure
Operating Condition
- Start the engine.
- Test-drive the vehicle from 1st gear to 2nd gear, then slow down and stop the vehicle.
- While pressing the brake pedal, shift the transmission to R position/mode.
- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the TCM memory. If the malfunction returns in the next (second) drive cycle, the shift position indicator blinks and a Confirmed DTC and the freeze data are stored. The MIL does not come on.
Conditions for clearing the DTC
The shift position indicator comes off by turning the vehicle to the OFF (LOCK) mode. The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool clear command.