diff --git a/include/cantera/oneD/Sim1D.h b/include/cantera/oneD/Sim1D.h
index 40f147f134..928624a767 100644
--- a/include/cantera/oneD/Sim1D.h
+++ b/include/cantera/oneD/Sim1D.h
@@ -41,7 +41,14 @@ class Sim1D : public OneDim
      */
     //@{
 
-    /// Set initial guess based on equilibrium
+    /// Set initial guess for one component for all domains
+    /**
+     * @param comp component name
+     * @param pos A vector of relative positions, beginning with 0.0 at the
+     *     left of the domain, and ending with 1.0 at the right of the domain.
+     * @param values A vector of values corresponding to the relative position
+     *     locations.
+     */
     void setInitialGuess(const std::string& component, vector_fp& locs,
                          vector_fp& vals);
 
diff --git a/src/oneD/Sim1D.cpp b/src/oneD/Sim1D.cpp
index e4224eb975..7639087e99 100644
--- a/src/oneD/Sim1D.cpp
+++ b/src/oneD/Sim1D.cpp
@@ -71,6 +71,11 @@ doublereal Sim1D::workValue(size_t dom, size_t comp, size_t localPoint) const
 void Sim1D::setProfile(size_t dom, size_t comp,
                        const vector_fp& pos, const vector_fp& values)
 {
+    if (pos.front() != 0.0 || pos.back() != 1.0) {
+        throw CanteraError("Sim1D::setProfile",
+            "`pos` vector must span the range [0, 1]. Got a vector spanning "
+            "[{}, {}] instead.", pos.front(), pos.back());
+    }
     Domain1D& d = domain(dom);
     doublereal z0 = d.zmin();
     doublereal z1 = d.zmax();