Bosch Dishwasher Intermittent E31 Error in Curlew Mobile Home Park, Palm Harbor
- Symptom
- Intermittent E31 error with no pattern; diagnostic test mode came back clean.
- Cause
- A slow leak from under the zeolite drying container gasket — its plastic nut had degraded — leaving gel-like residue around the float switch.
- Fix
- Replaced the plastic nut with a metal one, cleaned the sump, and tested several cycles.
A regular client at Curlew Mobile Home Park in Palm Harbor has a Bosch dishwasher (model SHP78CP5N/22) that was throwing an E31 error — but only sometimes, with no obvious pattern to which cycle it happened on.
An error that wouldn’t reproduce on demand
Running the dishwasher’s diagnostic test mode came back clean — no fault triggered. The E31 code only showed up in the fault history, not live. That kind of inconsistency usually means the trigger condition is only sometimes being met, so we opened the unit up to look closer.
Inside, we found water that had thickened into a gel-like residue sitting around the float switch — the safety leak switch that trips this error. Because the residue wasn’t always enough to fully lift the float, the error only fired intermittently instead of every cycle.
Tracing the leak to the zeolite container
The source turned out to be the zeolite container — the canister that holds the mineral pellets Bosch uses for its drying system. It was leaking from under the gasket where the container meets the housing.
The container’s original nut was plastic, and it had degraded enough to let the seal fail. The fix was to swap it for a metal replacement nut, which holds the gasket properly compressed and shouldn’t degrade the same way.
Cleaned up and retested
With the new metal nut in place, we cleaned the sump of the built-up residue, reassembled everything, and ran it through multiple cycles to confirm the leak was gone and the float switch was moving freely.
Result
No more E31, no more residue building up near the float switch. If your dishwasher throws an intermittent leak-related error that won’t reproduce in test mode, it’s worth checking whether something is dripping slowly into the base rather than assuming the float switch itself is bad. See our dishwasher repair page for what else we typically check.
FAQ
What does E31 mean on a Bosch dishwasher?
It's a leak-related error from the float (safety leak) switch in the base — water or residue lifting the float triggers it.
Why does the E31 error come and go?
With a slow leak, the residue only sometimes lifts the float enough to trip it, so the error appears intermittently and may not reproduce in test mode.