DTC : P0731 (6-Speed A/T) (2016 2017 2018 2019 2020): General Description
To engage 1st gear, line pressure is supplied to the 1st clutch piston, engaging the 1st clutch, and the secondary shaft and the secondary shaft 1st gear are connected and revolve together. Hydraulic pressure is supplied to the 1st clutch through the ATF strainer → the ATF pump → the main regulator valve → the manual valve → the shift valves → the feed pipe → the 1st clutch piston. (A shift valve failure in the supply route above is detected by the malfunction detection of each shift solenoid valve.) The powertrain control module (PCM) computes the ratio of the input shaft (mainshaft) speed to the output shaft (countershaft) speed. When the ratio is not the 1st gear ratio, the PCM detects a malfunction of the hydraulic circuit or the 1st clutch and stores a DTC.