diff --git a/testing/marionette/client/marionette/tests/unit/test_navigation.py b/testing/marionette/client/marionette/tests/unit/test_navigation.py
index 901f92f5774..b70e6b0835e 100644
--- a/testing/marionette/client/marionette/tests/unit/test_navigation.py
+++ b/testing/marionette/client/marionette/tests/unit/test_navigation.py
@@ -97,7 +97,7 @@ class TestNavigate(MarionetteTestCase):
             self.assertTrue(self.marionette.find_element("id", "mozLink"))
             self.fail("Should have thrown a MarionetteException")
         except MarionetteException as e:
-            self.assertEqual(str(e), "Error loading page, timed out")
+            self.assertTrue("Error loading page, timed out" in str(e))
         except Exception as inst:
             import traceback
             print traceback.format_exc()
diff --git a/testing/marionette/marionette-listener.js b/testing/marionette/marionette-listener.js
index 0561736f6bd..dc7fd980a3a 100644
--- a/testing/marionette/marionette-listener.js
+++ b/testing/marionette/marionette-listener.js
@@ -1093,24 +1093,26 @@ function goUrl(msg) {
   let start = new Date().getTime();
   let end = null;
   function checkLoad(){
+    checkTimer.cancel();
     end = new Date().getTime();
     let errorRegex = /about:.+(error)|(blocked)\?/;
     let elapse = end - start;
     if (msg.json.pageTimeout == null || elapse <= msg.json.pageTimeout){
       if (curWindow.document.readyState == "complete"){
+        removeEventListener("DOMContentLoaded", onDOMContentLoaded, false);
         sendOk(command_id);
-        checkTimer.cancel();
       }
       else if (curWindow.document.readyState == "interactive" && errorRegex.exec(curWindow.document.baseURI)){
+        removeEventListener("DOMContentLoaded", onDOMContentLoaded, false);
         sendError("Error loading page", 13, null, command_id);
       }
       else{
-        checkTimer.cancel();
         checkTimer.initWithCallback(checkLoad, 100, Ci.nsITimer.TYPE_ONE_SHOT);
       }
     }
     else{
-      sendError("Error loading page, timed out", 21, null, command_id);
+      removeEventListener("DOMContentLoaded", onDOMContentLoaded, false);
+      sendError("Error loading page, timed out (checkLoad)", 21, null, command_id);
     }
   }
   // Prevent DOMContentLoaded events from frames from invoking this code,
@@ -1124,8 +1126,8 @@ function goUrl(msg) {
   };
 
   function timerFunc(){
-    sendError("Error loading page, timed out", 21, null, command_id);
     removeEventListener("DOMContentLoaded", onDOMContentLoaded, false);
+    sendError("Error loading page, timed out (onDOMContentLoaded)", 21, null, command_id);
   }
   if (msg.json.pageTimeout != null){
     checkTimer.initWithCallback(timerFunc, msg.json.pageTimeout, Ci.nsITimer.TYPE_ONE_SHOT);