ick ▁sign alling ▁is ▁multiple x ed ▁on ▁a ▁single ▁wire . ▁The ▁transmission ▁control ▁module ▁outputs ▁a ▁ 5 v ▁signal ▁to ▁the ▁handle ▁and ▁mon itors ▁it ▁for ▁voltage ▁drop ▁The ▁voltage ▁ranges ▁ 0 . 3 - 1 . 6 , 1 . 6 - 2 . 8 , ▁ 2 . 8 - 3 . 8 , ▁and ▁ 3 . 8 - 4 . 8 ▁representing ▁down , ▁up , ▁over drive ▁lock out , ▁and ▁all ▁open ▁respectively . ▁The ▁vehicle ▁dro ps ▁into ▁ 1 st ▁after ▁stopping ▁but ▁can ▁be ▁launched ▁in ▁ 1 st , ▁ 2 nd , ▁or ▁ 3 rd ▁g ear . ▁The ▁speed ▁( or ▁cru ise ) ▁control ▁oper ates ▁only ▁in ▁ 3 rd ▁and ▁ 4 th ▁g ear ▁while ▁in ▁Aut ost ick ▁mode ▁and ▁is ▁de activ ated ▁if ▁shift ed ▁to ▁ 2 nd ▁g ear , ▁just ▁as ▁it ▁would ▁if ▁the ▁driver ▁had ▁bra ked . ▁Sh ifting ▁into ▁ 4 th ▁( aka ▁D ) ▁can c els ▁Aut ost ick ▁single ▁g ear ▁selection ▁mode , ▁and ▁g ears ▁are ▁automatically ▁selected ▁as ▁usual ▁until ▁down ▁or ▁O D ▁lock out ▁is ▁pressed . ▁ ▁System ▁fails af es ▁In ▁modern ▁implementations ▁if ▁the ▁user ▁does ▁not ▁shift ▁while ▁driving ▁in ▁the ▁Aut ost ick ▁mode , ▁the ▁transmission ▁will ▁automatically ▁up - shift ▁at ▁red line ▁( the ▁exception ▁being ▁the ▁P ly mouth / Ch rys ler