my son was traveling to Phoenix, rough road and his abs light came on(01' 3/4 quad cab short bed 4x4 6-speed cummins), he had Dodge run a scan, the following codes came up! 74, 67, 65, 23 & 21; he had replaced ther sensor in the rear differential, does anyone have any ideas or can someone direct me to the code definitions, thanks for any help you can provide!! he's been to Iraq and going back, want to get his truck fixed before he leaves again