Yehweh is a spelling, or some would argue a mis-spelling of Yahweh which is one of the Hebrew names of God in the bible.
With the coming of His Son to the earth, God revealed that He is our Savior by means of His Son (see 1 Tim. 1:1; 1 Tim. 2:3-5; Titus 3:4-6; Jude 24-25; and Rev. 7:10 in the Bible). Also, by this time the Jews had refused to ever say God’s name (“Yehweh”) out of fear that they might use His name in vain. So, God modified His Hebrew name (“YHWH” – “Yehweh”) to reflect that He and His Son were no longer just our God, but also our Savior, by adding the Hebrew word for “Savior” to the end of the abbreviation of His name (“YH” – “Yeh” – “I am”), which makes God’s name now “Yesu,” since this in Hebrew actually means “Yeh(weh)-Savior.” Plus, like human fathers down through the generations, He also gave His name to His Son (see John 17:11-12).