DTC Advanced Diagnostics: P0751
DTC P0751:Shift Solenoid Valve A 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 A 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 A. 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 A from the PCM is on, and the line pressure is applied to shift valve A, it operates against the shift valve A spring. When the signal to shift solenoid valve A from the PCM is off, and the line pressure is discharged, shift valve A 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 A stuck off failure and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status
Execution
Continuous
Sequence
None
Duration
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, S
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, P0752, P0756, 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
[ ]: HDS Parameter

Malfunction Threshold
Symptom 1 occurs:

Symptom
Gear position commanded by the PCM
Actual gear position
1
Driving in 2nd gear
Driving in 5th 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 A stuck off
Shift valve A failure

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, the A/T gear position indicator blinks, and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC
The A/T gear position indicator comes off by pressing the engine start/stop button to select the OFF mode. 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.