diff --git a/psycopg/psycopgmodule.c b/psycopg/psycopgmodule.c
index 36fd1f9c..2a4c9e6a 100644
--- a/psycopg/psycopgmodule.c
+++ b/psycopg/psycopgmodule.c
@@ -770,9 +770,8 @@ sqlstate_errors_init(PyObject *module)
     Dprintf("psycopgmodule: initializing sqlstate exceptions");
 
     if (sqlstate_errors) {
-        PyErr_SetString(PyExc_SystemError,
-            "sqlstate_errors_init(): already called");
-        goto exit;
+		Dprintf("sqlstate_errors_init(): already called");
+        return 0;
     }
     if (!(errmodule = PyImport_ImportModule("psycopg2.errors"))) {
         /* don't inject the exceptions into the errors module */