diff --git a/module_build_service/scm.py b/module_build_service/scm.py
index cace0e8a..123cdd8c 100644
--- a/module_build_service/scm.py
+++ b/module_build_service/scm.py
@@ -134,7 +134,7 @@ class SCM(object):
         if stderr:
             log.warning(stderr)
         if proc.returncode != 0:
-            raise RuntimeError("Failed on %r, retcode %r, out %r, err %r" % (
+            raise UnprocessableEntity("Failed on %r, retcode %r, out %r, err %r" % (
                 cmd, proc.returncode, stdout, stderr))
         return proc.returncode, stdout, stderr
 
@@ -186,7 +186,7 @@ class SCM(object):
         """
         if self.scheme == "git":
             log.debug("Getting/verifying commit hash for %s" % self.repository)
-            output = SCM._run(["git", "ls-remote", self.repository, branch])[1]
+            output = SCM._run(["git", "ls-remote", "--exit-code", self.repository, branch])[1]
             if output:
                 self.commit = output.split("\t")[0]
                 return self.commit
diff --git a/tests/test_scm.py b/tests/test_scm.py
index 2f500a2e..7162a03b 100644
--- a/tests/test_scm.py
+++ b/tests/test_scm.py
@@ -65,8 +65,10 @@ class TestSCMModule(unittest.TestCase):
         scm = module_build_service.scm.SCM(repo_path)
         assert scm.scheme == 'git', scm.scheme
         fname = tempfile.mktemp(suffix='mbs-scm-test')
-        scm.get_latest(branch='master; touch %s' % fname)
-        assert not os.path.exists(fname), "%r exists!  Vulnerable." % fname
+        try:
+            scm.get_latest(branch='master; touch %s' % fname)
+        except UnprocessableEntity:
+            assert not os.path.exists(fname), "%r exists!  Vulnerable." % fname
 
     def test_local_extract_name(self):
         scm = module_build_service.scm.SCM(repo_path)
@@ -115,3 +117,8 @@ class TestSCMModule(unittest.TestCase):
         scm.checkout(self.tempdir)
         scm.verify()
         scm.get_module_yaml()
+
+    @raises(UnprocessableEntity)
+    def test_get_latest_incorect_component_branch(self):
+        scm = module_build_service.scm.SCM(repo_path)
+        scm.get_latest(branch='foobar')