DTC P0756
DTC P0756: Shift Solenoid Valve B Stuck OFF
General Description
Hydraulic pressure supply to the clutch by shift solenoid valve output (D position)
| Gear position | Shift solenoid valve | Clutch | ||||||
|---|---|---|---|---|---|---|---|---|
| A | B | 1st | 2nd | 3rd | 4th | 5th | 6th | |
| Neutral-1st | ON | OFF | CPCD | - | - | - | - | - |
| 1st | ON | ON | LINE | CPCA | CPCB | CPCC | - | - |
| 1st-2nd | ON | ON | LINE | CPCA | CPCB | CPCC | - | - |
| 2nd | ON | ON | LINE | CPCA | CPCB | CPCC | - | - |
| 2nd-3rd | ON | ON | LINE | CPCA | CPCB | CPCC | - | - |
| 3rd | OFF | ON | LINE | - | CPCB | CPCC | CPCA | - |
| 3rd-4th | OFF | ON | LINE | - | CPCB | CPCC | CPCA | - |
| 4th | OFF | OFF/(ON) | LINE | - | (CPCB) | CPCC | CPCA | CPCB |
| 4th-5th | OFF | OFF | LINE | - | - | CPCC | CPCA | CPCB |
| 5th | OFF | OFF/(ON) | LINE | - | (CPCB) | CPCC | CPCA | CPCB |
| 5th-6th | OFF | OFF | LINE | - | - | CPCC | CPCA | CPCB |
| 6th | OFF | OFF | LINE | - | - | CPCC | CPCA | CPCB |
LINE : Line pressure
CPCA: A/T clutch pressure control solenoid valve A pressure
CPCB: A/T clutch pressure control solenoid valve B pressure
CPCC: A/T clutch pressure control solenoid valve C pressure
CPCD: A/T clutch pressure control solenoid valve D pressure
Shift solenoid valve B is installed on the transmission housing. It is controlled by the ON/OFF signal from the powertrain control module (PCM) to apply line pressure to shift valve B. A signal from the PCM is output to apply A/T clutch pressure control solenoid valve pressure to the correct gear clutch according to the shift schedule. When the signal to shift solenoid valve B from the PCM is on, and the line pressure is applied to shift valve B, it operates against the shift valve B spring. When the signal to shift solenoid valve B from the PCM is off, and the line pressure is discharged, shift valve B is inactive. The PCM monitors the input shaft (mainshaft) speed and the output shaft (countershaft) speed according to the shift status determined by the shift schedule. When an improper gear ratio is output for the shift schedule, the PCM detects a shift solenoid valve B stuck off failure and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type, OBD Status
| Execution | Continuous | |
| Sequence | None | |
| Duration | Symptom 1 | 4 seconds or more |
| Symptom 2 | 1.5 seconds or more | |
| DTC Type | Two drive cycles, MIL on, A/T gear position indicator blinks | |
| OBD Status | PASSED/FAILED/NOT COMPLETED (STILL TESTING) | |
Enable Conditions
| Condition | Minimum | Maximum | |
|---|---|---|---|
| Vehicle speed [VEHICLE SPEED]* |
4 mph (7 km/h) | - | |
| Battery voltage [BATTERY VOLTAGE] |
11 V | - | |
| Shift lever position | D | ||
| No active DTCs set (prevents monitor from running) | P0122, P0123, P0222, P0223, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0351, P0352, P0353, P0354, P0355, P0356, P0705, P0716, P0717, P0718, P0721, P0722, P0723, P0746, P0747, P0751, P0752, P0757, P0761, P0762, P0776, P0777, P0796, P0797, P0842, P0843, P0847, P0848, P0872, P0873, P0877, P0878, P0962, P0963, P0966, P0967, P0970, P0971, P0973, P0974, P0976, P0977, P0979, P0980, P0989, P0990, P1658, P1659, P1683, P1684, P2101, P2118, P2122, P2123, P2127, P2128, P2135, P2138, P2176, P2648, P2649, P2653, P2654, P2658, P2659, P2714, P2720, P2721 | ||
* : Symptom 2
[ ]: HDS Parameter
Malfunction Threshold
One of these conditions occurs:
- Driving in 2nd or 5th gear after Symptom 1 occurred.
- Symptom 2 occurs.
Symptom 1
| Symptom | Gear position commanded by the PCM | Actual gear position | |
|---|---|---|---|
| 1 | Driving in 1st gear | Neutral | |
Symptom 2
| Symptom | Gear position commanded by the PCM | Actual gear position | |
|---|---|---|---|
| 2 | Driving in 3rd gear | Driving in 6th gear | |
Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- Shift solenoid valve B stuck off
- Shift valve B failure
- Shift valve C failure (Symptom 1)
- 1st gear one-way clutch failure (Symptom 1)
Confirmation Procedure
Operating Condition
- 1.
Start the engine.
- 2.
Drive the vehicle in D until the transmission shifts into 6th gear.
- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
With the HDS
None.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.
Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.