diff --git a/openedx/core/djangoapps/heartbeat/default_checks.py b/openedx/core/djangoapps/heartbeat/default_checks.py
index 925afe3a9b..164fb5a221 100644
--- a/openedx/core/djangoapps/heartbeat/default_checks.py
+++ b/openedx/core/djangoapps/heartbeat/default_checks.py
@@ -3,23 +3,27 @@ A set of built-in default checks for the platform heartbeat endpoint
 
 Other checks should be included in their respective modules/djangoapps
 """
+from __future__ import absolute_import
+
 from datetime import datetime, timedelta
 from time import sleep, time
 
+import six
 from django.conf import settings
 from django.core.cache import cache
 from django.db import connection
 from django.db.utils import DatabaseError
-from xmodule.modulestore.django import modulestore
+
 from xmodule.exceptions import HeartbeatFailure
+from xmodule.modulestore.django import modulestore
 
 from .tasks import sample_task
 
-
 # DEFAULT SYSTEM CHECKS
 
 # Modulestore
 
+
 def check_modulestore():
     """ Check the modulestore connection
 
@@ -37,7 +41,7 @@ def check_modulestore():
         modulestore().heartbeat()
         return 'modulestore', True, u'OK'
     except HeartbeatFailure as fail:
-        return 'modulestore', False, unicode(fail)
+        return 'modulestore', False, six.text_type(fail)
 
 
 def check_database():
@@ -54,7 +58,7 @@ def check_database():
         cursor.fetchone()
         return 'sql', True, u'OK'
     except DatabaseError as fail:
-        return 'sql', False, unicode(fail)
+        return 'sql', False, six.text_type(fail)
 
 
 # Caching
@@ -74,7 +78,7 @@ def check_cache_set():
         cache.set(CACHE_KEY, CACHE_VALUE, 30)
         return 'cache_set', True, u'OK'
     except Exception as fail:
-        return 'cache_set', False, unicode(fail)
+        return 'cache_set', False, six.text_type(fail)
 
 
 def check_cache_get():
@@ -92,7 +96,7 @@ def check_cache_get():
         else:
             return 'cache_get', False, u'value check failed'
     except Exception as fail:
-        return 'cache_get', False, unicode(fail)
+        return 'cache_get', False, six.text_type(fail)
 
 
 # Celery
@@ -113,8 +117,8 @@ def check_celery():
         while expires > datetime.now():
             if task.ready() and task.result:
                 finished = str(time() - now)
-                return 'celery', True, unicode({'time': finished})
+                return 'celery', True, six.text_type({'time': finished})
             sleep(0.25)
         return 'celery', False, "expired"
     except Exception as fail:
-        return 'celery', False, unicode(fail)
+        return 'celery', False, six.text_type(fail)
diff --git a/openedx/core/djangoapps/heartbeat/runchecks.py b/openedx/core/djangoapps/heartbeat/runchecks.py
index 82d1e88d34..7d033101a0 100644
--- a/openedx/core/djangoapps/heartbeat/runchecks.py
+++ b/openedx/core/djangoapps/heartbeat/runchecks.py
@@ -1,3 +1,8 @@
+"""
+Code for system checks.
+"""
+from __future__ import absolute_import
+
 from importlib import import_module
 
 from django.conf import settings
diff --git a/openedx/core/djangoapps/heartbeat/tasks.py b/openedx/core/djangoapps/heartbeat/tasks.py
index 058eea8e02..d7ba1f6dff 100644
--- a/openedx/core/djangoapps/heartbeat/tasks.py
+++ b/openedx/core/djangoapps/heartbeat/tasks.py
@@ -1,6 +1,8 @@
 """
 A trivial task for health checks
 """
+from __future__ import absolute_import
+
 from celery.task import task
 
 
diff --git a/openedx/core/djangoapps/heartbeat/tests/test_heartbeat.py b/openedx/core/djangoapps/heartbeat/tests/test_heartbeat.py
index a1282818c9..b1a029916c 100644
--- a/openedx/core/djangoapps/heartbeat/tests/test_heartbeat.py
+++ b/openedx/core/djangoapps/heartbeat/tests/test_heartbeat.py
@@ -1,16 +1,17 @@
 """
 Test the heartbeat
 """
-from __future__ import print_function
+from __future__ import absolute_import, print_function
+
 import json
 
-from django.urls import reverse
 from django.db.utils import DatabaseError
 from django.test.client import Client
-from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
+from django.urls import reverse
 from mock import patch
 
 from xmodule.exceptions import HeartbeatFailure
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 
 
 class HeartbeatTestCase(ModuleStoreTestCase):
diff --git a/openedx/core/djangoapps/heartbeat/urls.py b/openedx/core/djangoapps/heartbeat/urls.py
index 652bbdee46..5d49ace2de 100644
--- a/openedx/core/djangoapps/heartbeat/urls.py
+++ b/openedx/core/djangoapps/heartbeat/urls.py
@@ -1,6 +1,8 @@
 """
 Urls for verifying health (heartbeat) of the app.
 """
+from __future__ import absolute_import
+
 from django.conf.urls import url
 
 from openedx.core.djangoapps.heartbeat.views import heartbeat
diff --git a/openedx/core/djangoapps/heartbeat/views.py b/openedx/core/djangoapps/heartbeat/views.py
index 0224f653d7..b61071c99c 100644
--- a/openedx/core/djangoapps/heartbeat/views.py
+++ b/openedx/core/djangoapps/heartbeat/views.py
@@ -1,6 +1,10 @@
 """
 Views for verifying the health (heartbeat) of the app.
 """
+from __future__ import absolute_import
+
+import six
+
 from util.json_request import JsonResponse
 
 from .runchecks import runchecks
@@ -22,6 +26,6 @@ def heartbeat(request):
                 status_code = 503  # 503 on any failure
     except Exception as e:
         status_code = 503
-        check_results = {'error': unicode(e)}
+        check_results = {'error': six.text_type(e)}
 
     return JsonResponse(check_results, status=status_code)