Why Toro ECX Controller Only Programs Zones 1‑4 and Ignores 5‑6

A user with a 6‑station Toro ECX controller finds that manual operation works for all six zones, but automatic programming only allows zones 1‑4. Swapping wires confirms the valves themselves are functional.

Root Cause

The controller uses plug‑in expansion modules for additional zones. Zones 5‑6 require a second 2‑zone module that plugs into the back of the controller. If that module isn’t fully seated, the controller won’t recognize the extra zones.

Fix

1. Power off the controller.
2. Remove the expansion module for zones 5‑6.
3. Re‑insert it firmly until you hear a click, ensuring full engagement.
4. Restore power and verify that zones 5‑6 now appear in programming.

Note: Start times are limited to four per program, but that’s separate from zone count.