diff --git a/compact/gem_tracker_endcap.xml b/compact/gem_tracker_endcap.xml
index 00357f9f0736e0d8d66235370dca0246d9b2e3bf..0752cfb9a9de62a0f7aacdba30ae17341ff011a0 100644
--- a/compact/gem_tracker_endcap.xml
+++ b/compact/gem_tracker_endcap.xml
@@ -216,7 +216,7 @@
   <readouts>
     <readout name="GEMTrackerEndcapHits">
       <segmentation type="CartesianGridXZ" grid_size_x="50*um" grid_size_z="250*um" />
-      <id>system:8,barrel:2,layer:4,module:12,sensor:2,x:32:-16,y:-16</id>
+      <id>system:8,barrel:2,layer:4,module:12,sensor:2,x:32:-16,z:-16</id>
     </readout>
   </readouts>