diff --git a/Tools/autotest/arducopter.py b/Tools/autotest/arducopter.py
index 8b9524d355..28daeab809 100644
--- a/Tools/autotest/arducopter.py
+++ b/Tools/autotest/arducopter.py
@@ -2102,7 +2102,7 @@ class AutoTestCopter(AutoTest):
             # ignore the first 20Hz and look for a peak at -15dB or more
             ignore_bins = 20
             freq = psd["F"][numpy.argmax(psd["X"][ignore_bins:]) + ignore_bins]
-            if numpy.amax(psd["X"][ignore_bins:]) < -15 or freq < 200 or freq > 300:
+            if numpy.amax(psd["X"][ignore_bins:]) < -15 or freq < 180 or freq > 300:
                 raise NotAchievedException("Did not detect a motor peak, found %f at %f dB" % (freq, numpy.amax(psd["X"][ignore_bins:])))
             else:
                 self.progress("Detected motor peak at %fHz" % freq)
@@ -2125,10 +2125,11 @@ class AutoTestCopter(AutoTest):
             self.do_RTL()
             psd = self.mavfft_fttd(1, 0, tstart * 1.0e6, tend * 1.0e6)
             freq = psd["F"][numpy.argmax(psd["X"][ignore_bins:]) + ignore_bins]
-            if numpy.amax(psd["X"][ignore_bins:]) < -30:
-                self.progress("Did not detect a motor peak, found %f at %f dB" % (freq, numpy.amax(psd["X"][ignore_bins:])))
+            peakdB = numpy.amax(psd["X"][ignore_bins:])
+            if peakdB < -23:
+                self.progress("Did not detect a motor peak, found %f at %f dB" % (freq, peakdB))
             else:
-                raise NotAchievedException("Detected motor peak at %f Hz" % (freq))
+                raise NotAchievedException("Detected peak %.1f Hz %.2f dB" % (freq, peakdB))
         except Exception as e:
             ex = e