diff --git a/psycopg/error_type.c b/psycopg/error_type.c
index 21b0c4ef..da3056b7 100644
--- a/psycopg/error_type.c
+++ b/psycopg/error_type.c
@@ -90,6 +90,8 @@ error_init(errorObject *self, PyObject *args, PyObject *kwargs)
 static int
 error_traverse(errorObject *self, visitproc visit, void *arg)
 {
+    Py_VISIT(self->pgerror);
+    Py_VISIT(self->pgcode);
     Py_VISIT(self->cursor);
     return ((PyTypeObject *)PyExc_StandardError)->tp_traverse(
         (PyObject *)self, visit, arg);
@@ -101,8 +103,10 @@ error_clear(errorObject *self)
     Py_CLEAR(self->pgerror);
     Py_CLEAR(self->pgcode);
     Py_CLEAR(self->cursor);
+
     PyMem_Free(self->codec);
     CLEARPGRES(self->pgres);
+
     return ((PyTypeObject *)PyExc_StandardError)->tp_clear((PyObject *)self);
 }