diff --git a/qwt/plot.py b/qwt/plot.py
index 298382c..1e46d36 100644
--- a/qwt/plot.py
+++ b/qwt/plot.py
@@ -954,7 +954,7 @@ def updateAxes(self):
                 d.isValid = False
                 minValue = intv_i.minValue()
                 maxValue = intv_i.maxValue()
-                d.scaleEngine.autoScale(d.maxMajor, minValue, maxValue, stepSize)
+                minValue, maxValue, stepSize = d.scaleEngine.autoScale(d.maxMajor, minValue, maxValue, stepSize)
             if not d.isValid:
                 d.scaleDiv = d.scaleEngine.divideScale(
                     minValue, maxValue, d.maxMajor, d.maxMinor, stepSize