Index: django/db/models/fields/__init__.py
===================================================================
--- django/db/models/fields/__init__.py	(revision 6364)
+++ django/db/models/fields/__init__.py	(working copy)
@@ -13,7 +13,7 @@
 from django.core import validators
 from django import oldforms
 from django import newforms as forms
-from django.core.exceptions import ObjectDoesNotExist
+from django.core.exceptions import ObjectDoesNotExist, ImproperlyConfigured
 from django.utils.functional import curry
 from django.utils.itercompat import tee
 from django.utils.text import capfirst
@@ -226,7 +226,14 @@
                 value = int(value)
             except ValueError:
                 raise ValueError("The __year lookup type requires an integer argument")
-            return ['%s-01-01 00:00:00' % value, '%s-12-31 23:59:59.999999' % value]
+            try:
+                if settings.DATABASE_ENGINE == "sqlite3":
+                    date_start_format = '%s-01-01'
+                else:
+                    date_start_format = '%s-01-01 00:00:00'
+            except:
+                raise ImproperlyConfigured, "DATABASE_ENGINE not defined in settings.py"
+            return [date_start_format % value, '%s-12-31 23:59:59.999999' % value]
         raise TypeError("Field has invalid lookup: %s" % lookup_type)
 
     def has_default(self):