diff --git a/dumux/implicit/cellcentered/tpfa/localresidual.hh b/dumux/implicit/cellcentered/tpfa/localresidual.hh
index 7dbad984c29c769a2023ac93d8fc83b5b055cf4e..5a7b218c4f434ad0fed6ff1d317a1a8448e0ba5c 100644
--- a/dumux/implicit/cellcentered/tpfa/localresidual.hh
+++ b/dumux/implicit/cellcentered/tpfa/localresidual.hh
@@ -66,7 +66,7 @@ public:
 
 protected:
 
-    void computeFlux_(PrimaryVariables &flux, const SubControlVolumeFace &scvFace)
+    PrimaryVariables computeFlux_(const SubControlVolumeFace &scvFace)
     {
         if (!scvFace.boundary() /*TODO: || GET_PROP_VALUE(TypeTag, BoundaryReconstruction)*/)
         {