Prima dishwasher E4 error code
What E4 means on a Prima dishwasher
Leak detected in the base.
Meaning checked by NAC's engineers, 9 November 2026.
What our engineers say
When a Prima dishwasher shows E4, it means the machine has detected a leak in its base. You may hear beeping or see flashing lights, and the dishwasher may also stop draining.
Engineers sometimes find a faulty water inlet valve that lets water keep flowing into the machine even when it isn't in use. They also sometimes find a split or worn drain hose, either the one inside the machine or the one leading away from it, or a drain pump that has started to leak.
An engineer will usually look over the water inlet valve and the plumbing under the sink, check the hose connections, and run water through the machine to find where it is escaping. The repair is normally a matter of replacing whichever part is at fault, such as the inlet valve, a drain hose or the drain pump, and then testing that the dishwasher fills and drains without leaking. These parts often have to be ordered, so the repair may be finished at a second visit.
Written by our engineers from NAC's own jobs.
Faults this code turns up with
What our engineers found and fixed for each, from NAC's own repair records.
What we fixed. We'll add what our engineers found, the parts they fitted and what customers typically paid once enough of these repairs are confirmed. How we work out our figures.
Before you check anything yourself
- Switch the dishwasher off and unplug it, or turn it off at the isolator switch, before you touch anything. Our guide to safely isolating an appliance walks you through it.
- An error code tells you where to look, not that it's safe to take the dishwasher apart. Don't remove panels or covers to get at the parts it points to: that's an engineer's job.
- If it involves the mains supply, sealed parts, or you're not confident at any point, stop and book a qualified engineer rather than risk injury or further damage.
Rather leave it to us?
- Fixed-price quote before any work starts
- Same or next-day visits where available
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