DTC : P0729 (6-Speed A/T) (2016 2017 2018 2019 2020): General Description
To engage 6th gear, A/T clutch pressure control solenoid valve pressure is supplied to the 6th clutch piston, engaging the 6th clutch, and the mainshaft and the mainshaft 6th gear are connected and revolve together. Hydraulic pressure is supplied to the 6th clutch through the ATF strainer → the ATF pump → the main regulator valve → the manual valve → the A/T clutch pressure control solenoid valves → the shift valves → the feed pipe → the 6th clutch piston. (An A/T clutch pressure control solenoid valve failure and shift valve failure in the supply route above are detected by the malfunction detection of each 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 6th gear ratio, the PCM detects a malfunction of the hydraulic circuit or the 6th clutch and stores a DTC.