diff --git a/nosnoc/model.py b/nosnoc/model.py
index 0709984..dd8ba82 100644
--- a/nosnoc/model.py
+++ b/nosnoc/model.py
@@ -322,8 +322,8 @@ def preprocess_model(self, opts: NosnocOpts):
         self.std_compl_res_fun = ca.Function('std_compl_res_fun', [z, self.p], [std_compl_res])
         if opts.pss_mode == PssMode.STEWART:
             mu00_stewart = casadi_vertcat_list([ca.mmin(g_Stewart_list[ii]) for ii in range(n_sys)])
-            self.mu00_stewart_fun = ca.Function('mu00_stewart_fun', [self.x, self.p], [mu00_stewart])
-            self.g_Stewart_fun = ca.Function('g_Stewart_fun', [self.x, self.p], [g_Stewart])
+            self.mu00_stewart_fun = ca.Function('mu00_stewart_fun', [self.x, self.z, self.p], [mu00_stewart])
+            self.g_Stewart_fun = ca.Function('g_Stewart_fun', [self.x, self.z, self.p], [g_Stewart])
 
     def create_stage_vars(self, opts: NosnocOpts):
         """
diff --git a/nosnoc/solver.py b/nosnoc/solver.py
index 23f97a9..d8f8884 100644
--- a/nosnoc/solver.py
+++ b/nosnoc/solver.py
@@ -285,8 +285,8 @@ def create_function_calculate_vector_field(self, sigma, p=[], v=[]):
                 ca.sum1(theta)-1
             )
         ))
-        def fun(x, u):
-            g  = self.model.g_Stewart_fun(x, p)
+        def fun(x, u, z=[0]):
+            g  = self.model.g_Stewart_fun(x, z, p)
             theta = theta_fun(0, g)[:-1]
             F = self.model.F_fun(x, u, p, v)
             return np.dot(F, theta)
diff --git a/test/test_simple_car_algebraics.py b/test/test_simple_car_algebraics.py
new file mode 100644
index 0000000..56c3d15
--- /dev/null
+++ b/test/test_simple_car_algebraics.py
@@ -0,0 +1,12 @@
+import unittest
+from examples.simple_car_algebraics.simple_car_algebraic import solve_ocp
+
+
+class TestSimpleCarAlgebraics(unittest.TestCase):
+
+    def test_simple_solving(self):
+        solve_ocp()
+
+
+if __name__ == "__main__":
+    unittest.main()