What Does Error Code F43 Mean on a Bosch Washing Machine?
Check the drum for a physical obstruction by rotating it by hand with the machine unplugged — if it turns freely, reset the machine by unplugging it for 5 minutes and restarting the cycle to clear a temporary motor fault (takes about 10 minutes).
Fault description
Error code F43 means your Bosch washing machine has detected that the drum is not rotating as it should. The machine monitors motor speed and drum movement throughout every cycle, and when it cannot confirm the drum is turning correctly, it stops the programme and displays F43 to prevent damage to the motor or your laundry.
When this error appears, the wash cycle will halt mid-programme. You may notice the machine is silent where you would normally hear the drum turning, or it may make a humming sound as the motor attempts to run but fails to drive the drum. The door will remain locked while the fault is active.
The underlying cause can range from something as simple as a foreign object jamming the drum to worn motor brushes or a failing motor — so it is worth working through the checks in order before assuming the worst.
Causes
- Foreign object jamming the drum or drum bearing — Coins, bra underwires, or small items of clothing can become lodged between the drum and the door seal or inner tub, physically preventing the drum from rotating. This is one of the most common triggers for F43 and is often the easiest to resolve.
- Worn or failed carbon motor brushes — Bosch washing machines with brushed motors rely on carbon brushes to transfer electrical current to the motor. Over time these brushes wear down and lose contact, causing the motor to lose power intermittently or stop driving the drum altogether.
- Seized or failing drive motor — The motor itself can seize due to overheating, bearing failure, or general wear after years of use. A seized motor will often produce a humming noise as it tries to start but cannot turn the drum shaft.
- Worn or broken drive belt — Many Bosch washing machine models use a drive belt to connect the motor to the drum pulley. If this belt snaps or slips off, the motor will run but the drum will not move, triggering F43.
- Faulty motor control board or wiring — The motor control module regulates power delivery to the motor. A fault on this board, or damaged wiring between the board and the motor, can prevent the motor from receiving the correct signals to run.
- Overloaded drum — An excessively heavy load can place enough strain on the motor to prevent it from reaching the required speed, causing the machine to detect a drum fault. This is more likely to occur on older machines where motor performance has already declined slightly.
Step-by-Step Fix
- 1
Unplug the machine and check for obstructions
Switch the machine off at the wall and unplug it from the mains. Open the door and carefully run your hand around the rubber door seal, feeling for any trapped items such as coins, wires, or fabric. Try rotating the drum by hand — it should turn with moderate resistance. If it feels completely locked or grinds, there is likely a physical obstruction or a seized bearing.
- 2
Reduce the load and restart
If the drum was overloaded, remove roughly half the laundry and redistribute the remaining items evenly. Plug the machine back in, select a short cycle, and observe whether the drum begins to turn normally. An overload is a quick fix that takes only a few minutes to test.
- 3
Perform a power reset
Unplug the washing machine from the mains socket and leave it disconnected for at least 5 minutes. This allows the motor control electronics to fully reset. Plug back in, select a spin-only programme, and watch and listen to confirm whether the drum rotates. This resolves temporary motor control glitches that can trigger F43.
- 4
Inspect the drive belt
To access the drive belt you will need to remove the rear panel of the machine — unscrew the retaining screws around the panel edge and lift it away. Look at the large drum pulley and the motor pulley. If the belt is snapped, lying loose at the bottom of the machine, or visibly cracked and frayed, it needs replacing. Replacement belts are inexpensive and widely available for most Bosch models.
- 5
Check and replace the carbon brushes
With the rear panel removed, locate the motor — the carbon brushes are housed in small plastic holders on either side of the motor body. Slide or unscrew the brush holders out and inspect the brushes. If the carbon tip is shorter than approximately 5–6 mm or is visibly crumbled, the brushes are worn and should be replaced as a pair. New brushes are a low-cost part and fitting them is straightforward with basic tools.
- 6
Inspect motor wiring and connections
While the rear panel is off, check the wiring harness running to the motor for any signs of burning, chafing, or loose connectors. Press each connector firmly to ensure it is fully seated. Damaged wiring should be repaired or replaced before running the machine again, as poor connections can cause intermittent faults and further damage.
- 7
Test the motor directly
If all the above checks pass and the drum still does not turn, the motor itself may have failed. A multimeter can be used to test motor winding resistance — consult your model's service data for the expected values. A reading of zero (short circuit) or infinite resistance (open circuit) confirms a failed motor winding, meaning the motor needs to be replaced.
Affected models
Select your model to see its full troubleshooting page.
When to call a service technician
If you have checked for obstructions, replaced the drive belt, and fitted new carbon brushes but the drum still will not turn, the motor itself has likely failed or the motor control board is faulty. These components require accurate diagnosis with test equipment and, in the case of the control board, careful handling to avoid further damage.
You should also call a service technician if you notice any burning smell coming from the machine, scorch marks around the motor or wiring, or if the machine trips your household circuit breaker when it attempts to start. These are signs of an electrical fault that should not be investigated without professional knowledge.
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Frequently Asked Questions
Can I still use my Bosch washing machine while it shows F43?
No — when F43 is active the machine has stopped the cycle because the drum is not rotating safely. Running it in this state risks overheating the motor or causing further damage. Resolve the fault before using the machine again.
How do I know if it is the brushes or the motor that has failed?
Worn brushes typically cause the drum to turn intermittently or only at certain speeds before failing completely, and the machine may have been cutting out more frequently in the weeks before F43 appeared. A fully seized motor usually produces a humming sound with no drum movement at all from the first attempt. Inspecting the brush length is a quick visual check — if they are worn down, replace them first before assuming the motor is at fault.
How long do carbon brushes last in a Bosch washing machine?
Carbon brushes typically last between 5 and 10 years depending on how frequently the machine is used and the types of programmes selected. High-spin cycles place more demand on the motor and can accelerate brush wear. Replacing them proactively around the 7-year mark is a sensible precaution.
Will a new drive belt fix F43 if the drum turns freely by hand?
If the drum turns freely by hand but the machine shows F43, a broken belt is a strong possibility — the motor is running but not driving the drum. However, if the drum is stiff or locked, the belt is unlikely to be the sole cause and you should also check for obstructions and inspect the motor and bearings.
Is F43 on a Bosch washing machine an expensive repair?
It depends on the cause. Carbon brushes and drive belts are inexpensive parts, typically costing between £5 and £25, and can be fitted at home with basic tools. A replacement motor is more costly, usually £60–£150 for the part alone, and fitting it adds labour time. A motor control board replacement is the most expensive outcome and may not be economical on an older machine.