diff --git a/src/ModelingToolkit.jl b/src/ModelingToolkit.jl
index 89dee632f4..16e9ab6548 100644
--- a/src/ModelingToolkit.jl
+++ b/src/ModelingToolkit.jl
@@ -3,7 +3,7 @@ $(DocStringExtensions.README)
 """
 module ModelingToolkit
 using PrecompileTools, Reexport
-@recompile_invalidations begin 
+@recompile_invalidations begin
     using DocStringExtensions
     using Compat
     using AbstractTrees
diff --git a/src/systems/diffeqs/odesystem.jl b/src/systems/diffeqs/odesystem.jl
index 0abf12d26e..76c6c4a58a 100644
--- a/src/systems/diffeqs/odesystem.jl
+++ b/src/systems/diffeqs/odesystem.jl
@@ -386,9 +386,8 @@ function build_explicit_observed_function(sys, ts;
         push!(obsexprs, lhs ← rhs)
     end
 
-    pars = parameters(sys)
     if inputs !== nothing
-        pars = setdiff(pars, inputs) # Inputs have been converted to parameters by io_preprocessing, remove those from the parameter list
+        ps = setdiff(ps, inputs) # Inputs have been converted to parameters by io_preprocessing, remove those from the parameter list
     end
     if ps isa Tuple
         ps = DestructuredArgs.(ps, inbounds = !checkbounds)