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Bosch F43 on a washing machine

The drum did not reach the speed the board asked for.

The same code appears on Neff and Siemens machines — they share the same control platform.

Verdict

DIY-able with care

Involves dismantling or a part swap — confident DIYers only

Urgency
Fix soon

About 1 hr to work through

Typical cost

Free to £190

DIY: £8–£50 in parts

What F43 actually means

Closely related to F21, but where F21 tends to mean no rotation at all, F43 means rotation that never got up to the commanded speed. An overloaded or badly unbalanced drum is a genuinely common innocent cause, so try a bare-drum spin before assuming a part has failed.

Before you start

  • Electrical safety: If the fault persists with an empty drum, the next checks are inside the cabinet near mains wiring. Unplug before removing any panel.

What causes it, most likely first

  1. Overloaded or badly unbalanced drum

    Most likely

    A single heavy item such as a duvet, or a drum packed past capacity, prevents the machine safely reaching spin speed. The board gives up rather than shake the machine apart.

    How to check: Redistribute the load by hand and run a spin-only cycle. If it now spins, that was the cause.

  2. Worn motor carbon brushes

    Common

    Partly worn brushes deliver enough power to tumble but not enough to spin. A machine that washes fine but leaves clothes soaking is the classic presentation.

    Motor carbon brushes£8–£22 for the partDIY with care

  3. Slipping drive belt

    Common

    A glazed or stretched belt grips well enough at wash speeds and slips as the drum accelerates. Often accompanied by a smell of hot rubber.

    Drive belt£8–£22 for the partDIY with care

  4. Worn shock absorbers

    Occasional

    Dead dampers let the drum swing so far during acceleration that the machine aborts the spin for safety. Usually paired with violent knocking.

    Shock absorbers / dampers£20–£50 for the partDIY with care

  5. Tacho or motor fault

    Occasional

    A degraded speed sensor reports a lower speed than the drum is really doing, so the board keeps pushing and eventually errors out.

    Drive motor£60–£160 for the partEngineer

How to fix it, step by step

  1. Redistribute the load and try again

    Open the door, pull everything apart by hand — wet washing knots into a single mass — and spread it evenly round the drum. Run a spin-only cycle.

    5 min

  2. Try a completely empty spin

    Take everything out and run a spin-only programme on a bare drum. A machine that spins up perfectly empty has a loading problem, not a mechanical one.

    10 min

  3. Check the machine is level and stable

    Push down on each front corner in turn. Any rock means the feet need adjusting. An unstable machine reaches its safety limits far earlier than a level one.

    10 minSpanner for the feet

  4. If a bare drum still fails, suspect brushes or belt

    Both are inexpensive parts behind the rear panel. If you are comfortable working inside an isolated appliance this is a realistic DIY job; if not, it is a short engineer visit and one of the cheaper repairs on a washing machine.

    60 min

Need an engineer for this F43?

We list 83 washing machine repair businesses across the UK, 41 of which are Bosch-authorised. Diagnostic callouts typically start around £55, and many will put that towards the repair if you go ahead.

Find washing machine engineers near you

Parts you might need

Typical UK prices for the part alone, before fitting. Worth knowing before you accept a quote — the part is often a small share of what a repair is priced at.

  • Motor carbon brushes

    Two sacrificial carbon blocks that carry current into a brushed motor. They wear down over years and are a cheap, planned replacement.

    £8–£22

  • Drive belt

    Links the motor pulley to the drum pulley on belt-driven machines. A snapped belt gives you a motor that runs and a drum that does not.

    £8–£22

  • Shock absorbers / dampers

    Damp the drum as it accelerates into a spin. Worn ones let the drum hammer the cabinet on high spin speeds.

    £20–£50

  • Drive motor

    The motor that turns the drum. On most machines a genuine replacement costs enough to trigger a repair-or-replace decision.

    £60–£160

Worth repairing, or replace it?

At the top of this range the repair costs a significant share of a graded replacement, which typically starts around £200. Worth getting the quote first, then deciding — on a machine under about five years old a repair usually still wins.

Work out if it's worth fixingCompare graded washing machines

Related problems

Other Bosch washing machines codes

All Bosch washing machines fault codes