diff --git a/psycopg/typecast_array.c b/psycopg/typecast_array.c
index 75fa1cfa..4da11b4f 100644
--- a/psycopg/typecast_array.c
+++ b/psycopg/typecast_array.c
@@ -212,8 +212,10 @@ typecast_array_scan(const char *str, Py_ssize_t strlength,
             PyList_Append(array, sub);
             Py_DECREF(sub);
 
-            if (stack_index == MAX_DIMENSIONS)
+            if (stack_index == MAX_DIMENSIONS) {
+                PyErr_SetString(DataError, "excessive array dimensions");
                 return -1;
+            }
 
             stack[stack_index++] = array;
             array = sub;
@@ -224,8 +226,10 @@ typecast_array_scan(const char *str, Py_ssize_t strlength,
         }
 
         else if (state == ASCAN_END) {
-            if (stack_index == 0)
+            if (stack_index == 0) {
+                PyErr_SetString(DataError, "unbalanced braces in array");
                 return -1;
+            }
             array = stack[--stack_index];
         }
 
@@ -253,7 +257,7 @@ typecast_GENERIC_ARRAY_cast(const char *str, Py_ssize_t len, PyObject *curs)
     if (str[0] == '[')
         typecast_array_cleanup(&str, &len);
     if (str[0] != '{') {
-        PyErr_SetString(Error, "array does not start with '{'");
+        PyErr_SetString(DataError, "array does not start with '{'");
         return NULL;
     }
 
diff --git a/tests/test_types_basic.py b/tests/test_types_basic.py
index 737b3770..9a90ccdc 100755
--- a/tests/test_types_basic.py
+++ b/tests/test_types_basic.py
@@ -200,6 +200,13 @@ class TypesBasicTests(unittest.TestCase):
         r = self.execute("SELECT %s AS foo", (ss,))
         self.failUnlessEqual(ss, r)
 
+    def testArrayMalformed(self):
+        curs = self.conn.cursor()
+        ss = ['', '{}}', '{' * 20 + '}' * 20]
+        for s in ss:
+            self.assertRaises(psycopg2.DataError,
+                psycopg2.extensions.STRINGARRAY, b(s), curs)
+
     @testutils.skip_from_python(3)
     def testTypeRoundtripBuffer(self):
         o1 = buffer("".join(map(chr, range(256))))