The invention relates to a coupling unit (16) for connecting refrigerant lines (11) of a refrigerant circuit (10), in particular for cooling a vehicle drive module, said coupling unit including an expansion valve (20) accommodated in the coupling unit (16), said expansion valve (20) separating the refrigerant circuit (10) into a first and a second sub-areas (30, 32), said coupling unit (16) being connected directly to a refrigerant feed and a refrigerant return for an evaporator (26), said coupling unit (16) respectively comprising a coupling connection (36, 38) of the refrigerant feed and the refrigerant return, which are detachably connected to the expansion valve (20) via a common fastening device (44), and with the common fastening device (44) having at least one fastening element (48) that is accessible for connecting and disconnecting from a side of the expansion valve (20) that faces away from the coupling connections (36, 38).