logo elektroda
logo elektroda
X
logo elektroda

Bosch Dishwasher Tap Error & Rinse Aid LED Flashing: Water Inlet, Rinse Aid, Heating Faults

User question

bosch dishwasher error tap and rinse aid led flashing

Artificial Intelligence Response

Direct answer to the question

• On most recent Bosch dishwashers that have LEDs instead of a text display, a flashing “Tap/Water-Supply” LED combined with a flashing “Rinse-Aid” LED is interpreted by the control board as “the appliance did not succeed in filling within the allowed time.”
• In >90 % of service calls the root cause is restricted or zero water flow (closed tap, kinked or blocked hose, clogged inlet filter, or a failed Aqua-Stop / inlet valve).
• The rinse-aid light merely joins the tap light to “build” the fault code; it almost never means the dispenser is empty—even if it is, the dishwasher will run.
• Therefore start with the water-supply chain, then clear the base pan/float switch (models with leak protection), and finally consider electronic faults if the error persists.


Detailed problem analysis

  1. How the dishwasher decides to show this fault
    • At the beginning of every cycle the electronic controller opens the inlet valve and watches the flow sensor (or counts motor revolutions on circulation-pump-less models).
    • If the programmed volume (≈3–4 litres) is not reached within ~1 min, the controller aborts filling, drains any water already in the sump, and flashes the fault LEDs.
    • On fully-integrated Series 4/6/8 units the same situation would be shown as error E17 (timeout or flow sensor) or E16 (valve cannot close)​; on compact SKS models it is E15 (water detected in base)​​. Without a display Bosch “codes” these errors by combining LEDs, most commonly Tap + Rinse Aid.

  2. Typical hardware culprits
    a) External supply
    – Tap not fully open, service cock scaled-up, or building work temporarily reducing pressure (<0.3 bar).
    – Inlet hose kinked behind the cabinet.
    – Frozen hose in garages/holiday homes.
    b) Inlet filtration
    – Fine-mesh screen in the hose end or Aqua-Stop housing blocked by limescale or rust particles.
    – Secondary screen on the dishwasher’s inlet valve blocked.
    c) Valve & safety devices
    – Aqua-Stop solenoid coil open-circuit or jammed plunger.
    – Internal flow sensor jammed by debris or air-locked.
    – Float switch in the base pan lifted by leaked water ⇒ controller refuses to fill (E15 pattern).
    d) Control electronics
    – Triac or relay on the main board no longer energises the valve.
    – Brown-out/over-voltage corrupting the stored parameters (rare; cleared by hard reset).

  3. Why the Rinse-Aid LED also flashes
    • On non-display models Bosch uses binary coding: different combinations of LEDs ≈ different E-codes.
    • “Tap” on its own would denote any generic water problem; adding “Rinse-Aid” specifies the sub-category (timeout, leak, or sensor depending on model family).


Current information and trends

• Since 2021 Bosch/Siemens have gradually replaced mechanical flow meters with turbine-type Hall sensors; these are more accurate but more sensitive to sludge caused by over-dosing detergent tablets.
• New Aqua-Stop hoses integrate an electronic cycle counter. If the valve exceeds 15 000 open/close cycles a soft lock (“Tap” flashes) can occur; authorised service centres can reset or replace the hose.
• EU ecodesign regulation (EU) 2019/2022 requires dishwashers to survive 10 years of spare-part availability; Bosch now offers retrofit inlet valves for older SMS/SPS lines that tolerate lower mains pressure (down to 0.25 bar).


Supporting explanations and details

Cleaning the two inlet filters:

  1. Isolate mains and water, put a towel under the tap.
  2. Unscrew the hose at the tap. Pop out the stainless-steel mesh with needle-nose pliers, wash in vinegar if calcified.
  3. If fitted with Aqua-Stop, open its plastic bayonet cap and rinse the internal disc filter.
  4. Unscrew hose from dishwasher, locate the tiny cylindrical filter inside the valve body, flush both sides.
  5. Re-assemble, open tap, run a quick rinse cycle.

Entering service mode (example SMS46, may differ):
• Close door, power ON → press and hold “Start” until 0:01 appears, then press “+” three times.
• Error memory will show E-code (E15/E17). Note and clear by holding “Start” 5 s.


Ethical and legal aspects

• Working on a live appliance violates IEC 60364 and many local regulations; always isolate from mains.
• Water leakage interacting with 230 V circuitry is a shock and fire hazard—Bosch’s Aqua-Stop is a mitigative safety feature and must not be bypassed.
• Dispose of limescale remover chemicals according to local wastewater rules.


Practical guidelines (step-by-step)

  1. Hard reset: turn off breaker, wait 5 min, power up ⇒ sometimes clears EEPROM glitch.
  2. Verify external tap fully open; measure static pressure if possible (>0.3 bar).
  3. Pull appliance forward 10–15 cm, remove kick-strip, visually check for water in base pan (torch + mirror).
    – Dry with sponge/hairdryer; if float switch was lifted, error will clear next cycle.
  4. Clean both inlet filters (as above).
  5. Run a “Quick 45 °C” program and observe:
    – Hear valve click? → If silent and 230 V is present (measure), valve coil open ⇒ replace valve/hose.
    – Water trickles slowly? → suspect clogged filters or low pressure.
    – Fills then pumps out and faults again? → faulty flow sensor.
  6. If steps 1-5 fail, contact Bosch service; internal board or sensor parts require special fixture jig and parameter upload (BSH Connect).

Common pitfalls:
• Users mistake salt-re-fill LED for rinse-aid; confirm symbol.
• After kitchen renovation installers sometimes forget to punch out the spigot blank on the sink trap, causing drainback into base ⇒ float triggered.


Possible disclaimers or additional notes

• LED coding tables vary; consult the exact E-NR code (e.g. SMS46MI08E/44).
• Some US/Canada models (SHX series) use different icon combinations.
• A completely empty rinse-aid tank will not prevent a wash; it causes only a steady (not flashing) light.


Suggestions for further research

• Bosch Technical Service Manual “Dishwasher without Display – Fault Diagnosis via LED Coding” (BSH document 9000 986 333).
• Study of Hall-effect flow sensors in domestic appliances (Journal of Sensors, 2023).
• Emerging self-cleaning inlet-filter technology using piezo vibration (Fraunhofer IPK prototype).


Brief summary

A flashing Tap and Rinse-Aid LED on a Bosch dishwasher almost always flags a water-fill timeout. Start outside the machine (tap open, hose unkinked, filters clean), then check the leak float and inlet valve. After clearing the obstruction or replacing the faulty valve, reset the appliance; the LEDs should stop flashing and a normal program will start. If they persist, internal flow-sensor or control-board faults require professional service.

Ask additional question

Wait...(2min)
Disclaimer: The responses provided by artificial intelligence (language model) may be inaccurate and misleading. Elektroda is not responsible for the accuracy, reliability, or completeness of the presented information. All responses should be verified by the user.