Bosch washer error code F21

Bosch Washing Machine Error Code F21


There are some errors in the work of the washing machines, which appear to be really dangerous, so if you see an F21 code on the display of your appliance or a combination of blinking indicators 1000, 800 and rinsing (or 800, 600 and rinsing for the older models), instantly unplug and unfasten your washer from the water supply, and call the repairman.

The error occurs when the drum of the machine can not rotate. The washer tries to fix it with its self-control mechanisms, but after numerous attempts, the drum doesn’t start spinning and the code is indicated on the display.

What causes the F21 Error code?

So your washer didn’t start working, or just stopped rotating the drum while washing process. After the appliance tried to fix the issue and failed, it showed the F21 code on the control panel, and you immediately turned the machine off in order to avoid electric shock. Now its time to find out why this could happen and how big the danger is.

The first and the most simple thing, that can cause the drum cycle issues of the washer is the weak voltage, which has nothing to do with improper exploitation or serious parts damage. But, unfortunately, this is a very rare case.

Another easy solution — there is a foreign object in the tank, which prevents the ro-tation. You can check it by simply spinning the drum manually, and if you hear an abnormal sound — the mystery is solved. Actually, it is pretty dangerous, as sharp objects can pierce the tank or drum and cause the leakage, which can burn the electronic system of the appliance. So make sure you remove the foreign object as soon as you notice it.

Besides the simple explanations, there are a few severe ones, that will definitely need professional intervention. Here is what the explanation of the F21 Error code can be:

  1. The failure of the Hall sensor. This sensor, also known as the rotor position sensor, if the one, that controls the work of the engine during the washing cycle. So when it doesn’t receive data on the speed of the motor — it stops the operation of the machine and indicates the error code on the screen.
  2. The breakage of the motor. When it comes to troubles with the engine, the washer just can’t start running. After a few tries to begin the rotation process it gives up and indicates the error. Possibly, it can be explained by the failure of the engine’s brushes, which is a common thing for the Bosch appliances. Another probability is the motor leakage, in this case, you will have to replace the entire engine.
  3. One more explanation for this error code lays in between the motor and the sensor — in the chain, that powers them. In this case, both RPS and the engine are fine, but the wires of the chain have to be checked and replaced.

How to fix the F21 Error?

Bosch Washing Machine Error Code F21 check engine brushes

As we already mentioned, it is better to call the specialist as soon as your machine’s control panel indicates the F21 Error Code. But if you feel you are experienced enough, you can replace the engine brushes and even try to check the Hall sensor yourself.

After unplugging and disconnecting the machine, take off the rear wall and the transmission belt, in order to get a better entry to the engine.

The RPS is located on the case of the engine, so to get to it you will need to take off the motor. It is recommended to take a few photographs of the proper connections and wired before dividing the motor.

Bosch Washing Machine Error Code F21 checking the RPS with a multimeter

After you subtract the mechanism from the washer, you can take off the Hall sensor and carefully examine it, looking for signs of breakage. The reason may be in the dirt, which you have to clean off. But the most important step is checking the RPS with a multimeter. If it shows that the detector is out of order even after you cleaned it properly — it has to be replaced.

In case you found the reason and performed all the necessary actions, there is one thing about the F21 error code — it won’t disappear even after it is fixed, so you will have to reset the appliance manually, for it to start working normally again.

There are four steps to reset it after you put the program selector bar in the Off mode:

  1. Start spinning the bar, slowly, until you see the error code on the display.
  2. Press the drum rev button for several seconds.
  3. Switch the selector bar to Drain.
  4. Press the spin button.
    If you hear a sound and see the blinking, the system has been reset. If not — repeat all the steps once again.

If none of the above-mentioned steps helped to get rid of the error, you should call the expert, as the F21 can be much more than serious, especially in case of tank leakage.