DTC P0751: Shift Solenoid Valve A Stuck OFF: General Description

Shift solenoid valve A is installed in 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. The signal from the PCM is output to apply A/T clutch pressure control solenoid valve pressure to the proper gear clutch according to the gear change schedule. When the signal to shift solenoid valve A from the PCM is ON, and 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 line pressure is discharged, shift valve A is inactive. The PCM monitors the input shaft (mainshaft) speed and the output shaft (countershaft) speed at the gear change determined by the shift schedule. When an improper gear ratio is output compared to the predetermined gear change mode, the PCM detects a shift solenoid valve A OFF failure and stores a DTC.