diff --git a/src/fpakc.f90 b/src/fpakc.f90
index 18e27f0..921d4ac 100644
--- a/src/fpakc.f90
+++ b/src/fpakc.f90
@@ -66,7 +66,7 @@ PROGRAM fpakc
     timeStep = t
 
     ! Update Particle boundary models
-    call boundariesParticle_update
+    call boundariesParticle_update()
 
     ! Update EM boundary models
     call boundariesEM_update()