diff --git a/gammapy/datasets/evaluator.py b/gammapy/datasets/evaluator.py
index 160ad4c43..eb4cef4ec 100644
--- a/gammapy/datasets/evaluator.py
+++ b/gammapy/datasets/evaluator.py
@@ -387,8 +387,22 @@ class MapEvaluator:
         if self.model.apply_irf["edisp"]:
             return apply_edisp(npred, self.edisp)
         else:
+            # No edisp application: map from true to reco using identity if needed
             if "energy_true" in npred.geom.axes.names:
-                return apply_edisp(npred, self._edisp_diagonal)
+                if self.edisp is None:
+                    # Create identity EDispKernel from geom energy axes
+                    energy_axis_true = self.geom.axes["energy_true"].copy()
+                    energy_axis = self.geom.axes["energy"].copy()
+                    # If axes differ, we cannot map; assume same binning and rename
+                    if energy_axis_true.nbin != energy_axis.nbin:
+                        # Fallback: reuse one axis for both
+                        energy_axis = energy_axis_true.copy(name="energy")
+                    return apply_edisp(npred,
+                                     EDispKernel.from_diagonal_response(
+                                         energy_axis_true=energy_axis_true,
+                                         energy_axis=energy_axis))
+                else:
+                    return apply_edisp(npred, self._edisp_diagonal)
             else:
                 return npred