diff --git a/dumux/material/fluidsystems/h2o_n2_system.hh b/dumux/material/fluidsystems/h2o_n2_system.hh
index 21d73fefa4e1d09b2497afc217363a98d12f5414..89f289f0f2a5e6a875806f48fe21660a2a12c1ca 100644
--- a/dumux/material/fluidsystems/h2o_n2_system.hh
+++ b/dumux/material/fluidsystems/h2o_n2_system.hh
@@ -386,9 +386,6 @@ public:
                             Scalar pressure,
                             const FluidState &fluidState)
     {
-#warning Diffusion Coefficient switched off!!!
-        return 0;
-
         if (compIIdx > compJIdx)
             std::swap(compIIdx, compJIdx);