diff --git a/steam/guard.py b/steam/guard.py
index b4169d46..cd75a744 100644
--- a/steam/guard.py
+++ b/steam/guard.py
@@ -54,7 +54,7 @@
 from time import time
 from steam import webapi
 from steam.enums import ETwoFactorTokenType
-from steam.steamid import SteamID
+from steam.exceptions import SteamError
 from steam.core.crypto import hmac_sha1, sha1_hash
 from steam.enums.common import EResult
 from steam.webauth import MobileWebAuth
@@ -127,7 +127,10 @@ def _send_request(self, action, params):
 
         if isinstance(backend, MobileWebAuth):
             if not backend.logged_on:
-                raise SteamAuthenticatorError("MobileWebAuth instance not logged in")
+                raise SteamAuthenticatorError(
+                    message="MobileWebAuth instance not logged in",
+                    eresult=None,
+                )
 
             params['access_token'] = backend.oauth_token
             params['http_timeout'] = 10
@@ -135,22 +138,32 @@ def _send_request(self, action, params):
             try:
                 resp = webapi.post('ITwoFactorService', action, 1, params=params)
             except requests.exceptions.RequestException as exp:
-                raise SteamAuthenticatorError("Error adding via WebAPI: %s" % str(exp))
+                raise SteamAuthenticatorError(
+                    message="Error adding via WebAPI: %s" % str(exp),
+                    eresult=None,
+                )
 
             resp = resp['response']
         else:
             if not backend.logged_on:
-                raise SteamAuthenticatorError("SteamClient instance not logged in")
+                raise SteamAuthenticatorError(
+                    message="SteamClient instance not logged in",
+                    eresult=None,
+                )
 
             resp = backend.send_um_and_wait("TwoFactor.%s#1" % action,
                                             params, timeout=10)
 
             if resp is None:
-                raise SteamAuthenticatorError("Failed. Request timeout")
+                raise SteamAuthenticatorError(
+                    message="Failed. Request timeout",
+                    eresult=None,
+                )
             if resp.header.eresult != EResult.OK:
-                raise SteamAuthenticatorError("Failed: %s (%s)" % (resp.header.error_message,
-                                                                   repr(resp.header.eresult)))
-
+                raise SteamAuthenticatorError(
+                    message="Failed: %s (%s)" % (resp.header.error_message, repr(resp.header.eresult)),
+                    eresult=resp.header.eresult,
+                )
             resp = proto_to_dict(resp.body)
 
             if action == 'AddAuthenticator':
@@ -166,7 +179,10 @@ def add(self):
         :raises: :class:`SteamAuthenticatorError`
         """
         if not self.has_phone_number():
-            raise SteamAuthenticatorError("Account doesn't have a verified phone number")
+            raise SteamAuthenticatorError(
+                message="Account doesn't have a verified phone number",
+                eresult=None,
+            )
 
         resp = self._send_request('AddAuthenticator', {
             'steamid': self.backend.steam_id,
@@ -177,7 +193,10 @@ def add(self):
         })
 
         if resp['status'] != EResult.OK:
-            raise SteamAuthenticatorError("Failed to add authenticator. Error: %s" % repr(EResult(resp['status'])))
+            raise SteamAuthenticatorError(
+                message="Failed to add authenticator. Error: %s" % repr(EResult(resp['status'])),
+                eresult=resp['status'],
+            )
 
         self.secrets = resp
         self.steam_time_offset = int(resp['server_time']) - time()
@@ -203,7 +222,10 @@ def finalize(self, activation_code):
             return
         elif not resp['success']:
             self._finalize_attempts = 5
-            raise SteamAuthenticatorError("Failed to finalize authenticator. Error: %s" % repr(EResult(resp['status'])))
+            raise SteamAuthenticatorError(
+                message="Failed to finalize authenticator. Error: %s" % repr(EResult(resp['status'])),
+                eresult=resp['status'],
+            )
 
         self.steam_time_offset = int(resp['server_time']) - time()
 
@@ -222,9 +244,15 @@ def remove(self, revocation_code=None):
         :raises: :class:`SteamAuthenticatorError`
         """
         if not self.secrets:
-            raise SteamAuthenticatorError("No authenticator secrets available?")
+            raise SteamAuthenticatorError(
+                message="No authenticator secrets available?",
+                eresult=None,
+            )
         if not isinstance(self.backend, MobileWebAuth):
-            raise SteamAuthenticatorError("Only available via MobileWebAuth")
+            raise SteamAuthenticatorError(
+                message="Only available via MobileWebAuth",
+                eresult=None,
+            )
 
         resp = self._send_request('RemoveAuthenticator', {
             'steamid': self.backend.steam_id,
@@ -233,9 +261,11 @@ def remove(self, revocation_code=None):
         })
 
         if not resp['success']:
-            raise SteamAuthenticatorError("Failed to remove authenticator. (attempts remaining: %s)" % (
-                resp['revocation_attempts_remaining'],
-                ))
+            raise SteamAuthenticatorError(
+                message="Failed to remove authenticator. (attempts remaining: %s)" %
+                        (resp['revocation_attempts_remaining'],),
+                eresult=None,
+            )
 
         self.secrets.clear()
 
@@ -466,8 +496,14 @@ def validate_phone_number(self, phone_number):
         return resp
 
 
-class SteamAuthenticatorError(Exception):
-    pass
+class SteamAuthenticatorError(SteamError):
+    def __init__(self, message, eresult=None):
+        Exception.__init__(self, message, eresult)
+        self.message = message
+        self.eresult = EResult(eresult) if eresult is not None else None  #: :class:`.EResult`|:class:`None`
+
+    def __str__(self):
+        return "(%s) %s" % (self.eresult, self.message) if self.eresult is not None else self.message
 
 
 def generate_twofactor_code(shared_secret):