The TCM controls engine output torque and reduces transaxle output shaft torque fluctuation during auto shifting, and reduces shock occurring from the vehicle during shifting.
During auto shifting, the TCM sends the torque reduction request signal using the CAN system and temporarily reduces the engine output torque by the engine ignition timing retard control. As a result, transaxle output shaft torque fluctuation is reduced during auto shifting by smooth engagement of the clutch.
In addition, the TCM receives the engine output torque from the PCM via the CAN signal to determine the clutch engagement pressure according to the engine output torque. As a result, the clutch hydraulic control setting accuracy is increased and smooth shift performance is achieved.