PartsFinder UK

F21

Error code

high severity Bosch

F21 Error: Your Bosch dishwasher has stopped mid-cycle and is displayin

Your Bosch dishwasher has stopped mid-cycle and is displaying the F21 error code on its display panel. This indicates a drainage fault, meaning water isn't draining properly from the drum once the wash programme has finished. Whilst this sounds concerning, try not to worry—many F21 errors can be resolved without calling an engineer. The most common culprits behind drainage problems are relatively straightforward to investigate yourself. Start by checking the drain filter, which often becomes clogged with food particles and debris. You should also inspect the drain hose running from your dishwasher to your waste pipe, as blockages or kinks frequently restrict water flow. The spray arm can sometimes be obstructed too, preventing proper water circulation during washing. Less commonly, the pump itself may have failed, or there could be an issue with the door latch sensor. Before assuming the worst, however, it's worth spending thirty minutes investigating these components. Most of these checks require only basic tools and common sense. If you do identify a blockage or debris, clearing it often resolves the problem completely. Only if these checks reveal nothing should you consider booking a service visit.

Diagnostic Steps

  1. 1

    Step 1

    Check the pump filter for blockages (located at bottom front of machine)

  2. 2

    Step 2

    Inspect the drain hose for kinks or blockages

  3. 3

    Step 3

    Check the sink drain or standpipe is clear

  4. 4

    Step 4

    Run a spin/drain cycle to test

  5. 5

    Step 5

    If fault persists, the drain pump may require replacement

⚠️ Always disconnect your appliance from mains power before starting any repair. If in doubt, consult a qualified engineer.

Frequently Asked Questions

What does the F21 error mean on a Bosch dishwasher?↓
Your Bosch dishwasher has stopped mid-cycle and is displaying the F21 error code on its display panel. This indicates a drainage fault, meaning water isn't draining properly from the drum once the wash programme has finished. Whilst this sounds concerning, try not to worry—many F21 errors can be resolved without calling an engineer. The most common culprits behind drainage problems are relatively straightforward to investigate yourself. Start by checking the drain filter, which often becomes clogged with food particles and debris. You should also inspect the drain hose running from your dishwasher to your waste pipe, as blockages or kinks frequently restrict water flow. The spray arm can sometimes be obstructed too, preventing proper water circulation during washing. Less commonly, the pump itself may have failed, or there could be an issue with the door latch sensor. Before assuming the worst, however, it's worth spending thirty minutes investigating these components. Most of these checks require only basic tools and common sense. If you do identify a blockage or debris, clearing it often resolves the problem completely. Only if these checks reveal nothing should you consider booking a service visit.
Can I fix the F21 error myself?↓
Many F21 faults can be resolved by a competent DIYer. Always disconnect from mains power first. If unsure, consult a qualified engineer.

Quick Summary

Code
F21
Brand
Bosch
Parts to check
0