What E:18 Means
E:18 is the opposite of the high-pressure code: the machine asked for water and not enough arrived, so it waits, and then ends the programme. Bosch's chart treats low inlet pressure as the cause and then works outward, checking the valve's own resistance, the harness from the power module, and the voltage actually reaching the valve terminals during a fill.
Common Causes of E:18
- Blocked filter screen in the inlet hose coupling
- Shut-off valve partly closed or seized
- Inlet valve coil failed, or no voltage reaching it during fill
🔧 One Safe Check You Can Try
Check that the shut-off valve under the sink is fully open rather than just cracked, then unscrew the inlet hose at the tap end and rinse the small filter screen inside the coupling. A clogged inlet screen is the most common reason a healthy supply arrives as a trickle.
⚠ Why You Shouldn't Go Further Than That
- If the screen and the shut-off are clear, the remaining checks are voltage readings taken at the valve while the machine is filling, which is live work next to water.
- The measurement Bosch specifies compares valve resistance against a model-specific figure, and without it a good coil is easily condemned.
- Undoing the inlet hose without closing the supply first floods the cabinet base, where the power module lives.
- A hose coupling cross-threaded on refitting weeps slowly for weeks before anyone notices the cabinet floor swelling.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.