Error F21 in the Bosch Stiral Machine

If your Bosch washing machine once showed an error with code F21, and at the same time did not knock out a traffic jam or an automatic machine, you are still very lucky. With such an error, the masters strongly recommend immediately disconnecting the Bosch washer from the mains, and only then call a specialist. An independent search for a solution to the problem, and even with powered equipment, is fraught with electric shock. However, we will not scare you ahead of time, we will deal with this error in order.

Interpretation and description of the code

Error F21 in the Bosch washing machine can appear not only in the form of an alphanumeric code, but also in the form of a set of flashing indicators on the control panel. This is due to the fact that some models of Bosch washing machines do not have a display and, accordingly, the F21 code simply has nowhere to display.

The system of flashing indicators can recognize dozens of errors. Masters do this offhand, because they have extensive experience working with such machines. The user can also do this using a special table of error codes.

In the picture below, we showed how the F21 code is displayed on Boschs without a display. The following happens: the washing machine hangs up, stops responding to button presses and turns of the program selector knob, and at the same time three lights start to light or flash - 1000 revolutions, 800 revolutions and rinsing. If you have an older model of a washing machine that spin at a maximum of eight hundred revolutions, then the indicators of 800 revolutions, 600 revolutions and rinsing will light up.

The interpretation of this error is very simple, but this does not mean that it is also easy to find the reasons for its occurrence. Error code F21 is interpreted by the masters as: there is no possibility to rotate the drum of the Bosch washing machine. In fact, the machine several times tries to start the rotation and if it fails, the code F21 will appear on the control panel. Because of what did this code appear, why was the washing machine unable to start the rotation of the drum?

1. Faulty tachometer. The engine speed information is not transmitted to the control module, which means that it simply stops the Bosch machine and displays the F code
2. The engine is out of order. If the motor is broken, then it is not able to rotate the drum, respectively, the module, after several attempts to start the engine, produces the indicated error.
3. An open circuit that powers the motor or Hall sensor (tacho). In this case, the sensor and the engine are serviceable, but their wiring is disconnected, or the contacts are oxidized.
4. The cause of the F12 error can be a foreign object that accidentally landed in the tank during washing and jammed the drum.
5. The reason for the appearance of the F12 code can also be a voltage drop in the mains.

Hall sensor defective

Having deciphered the error F12 and determining the reasons for its occurrence, we ask ourselves new questions: how to fix the malfunction that generated the code, and most importantly, how to quickly find it and it is desirable, without involving a wizard. There are no universal recipes for troubleshooting, it is necessary in the order convenient for you to start checking all of the above causes until you come across a breakdown.

Let's start with the Hall sensor. Understand correctly, we have chosen this verification procedure not for practical reasons, but in order to more successfully structure the article. You will most likely choose a different order - from simple to complex, and that will be perfectly reasonable. For example, first check whether the rotation of the drum is difficult by foreign objects, then check the voltage in the mains and only then climb into the housing in order to test the engine and the Hall sensor.

However, we will not depart from the topic. Before us, in the first couple, there was a difficulty associated with gaining access to the tachometer and the motor of the Bosch washing machine. How to get to these parts?

• Slowly turn off the washing machine and pull it out somewhere where there is more free space.
• We dismantle the back wall of the washer body, after which we remove the drive belt, which will probably interfere with us.
• We photograph the location of wires and mounts on the phone so that we don’t mix anything up later and remove the engine.

To quickly remove the motor from the Bosch washing machine, you must first disconnect the chips with wires from the engine, then unscrew the retaining bolts, then press on the body of the part so that it moves slightly forward and pull it down.

The tachometer is located directly on the engine body, so we need to remove it and carefully examine it. There may be traces of oxide and grease on the inner surface of the tacho ring; they must be removed. Next, we take a device called a multimeter and check the Hall sensor, if it turns out that the tachogenerator has burned out, you will need to replace it immediately.

Engine problems

The Bosch Maxx 5 washing machine and other models of the Russian assembly are often "noted" in service centers as serious problems with the engine. The simplest thing that can happen to him is the problem with the brushes. Brushes on collector engines are erased quite often and their replacement for the master is a common thing. An amateur with brushes will have to tinker a bit, but still this repair is classified as simple, so you can do it yourself, especially if you read our publication How to change brushes on a Bosch washing machine?

It will be much worse if the motor gives a leakage of current to the housing, or several windings of the winding have been broken through. In this case, 99% need to change the entire motor. At least it will be cheaper to restore the old engine. But let's not talk about sad things, first you need to check everything. We configure our device (multimeter) and check the case for leakage. If there is no leak, then we check each coil of the winding, trying to detect a breakdown. The work is painstaking, but it will allow you to accurately determine whether the engine is working or not.

Other malfunctions

Before we move on to other malfunctions that give rise to the F21 error, let's figure out how to reset the error on the Bosch brand washer. Perhaps you ask, why bother to reset the error, because if you eliminate the cause, the error will disappear by itself? The problem is that the error will not disappear, even if you carry out the repair absolutely correctly. If you do not throw off the settings, the code will hang, preventing the typewriter from starting to work. How to throw a mistake on a Bosch typewriter?

1. Turn the program selector to the off position.
2. Turn the selector to spin. At this stage, you need to wait until the error is displayed again on the control panel.
3. Press and hold for a few seconds the button responsible for switching the speed of the drum, then release it.
4. Turn the program selector switch to the “drain” mode.
5. Press the speed button again and wait a few seconds.

If all the lights blink amicably and the machine sounds loudly, then everything went well, the error has been reset. But if after the last time you released the speed change button, nothing happened, then you need to repeat the above steps, since it was not possible to throw off the error.

We wrote above that the Bosch error F21 can be caused by some foreign object that got into the tank and this, by the way, is not uncommon. What our masters do not extract from the bowels of washing machines: coins, pins, bones from bras, buttons, small details from children's toys.

All this poses a danger to the details of the washing machine, because there were cases when sharp objects stuck between the tank and the drum pierced the tank and provoked a leak.

How to make sure that the drum is jamming a foreign object without dismantling the washer? It is necessary to open the door of the hatch of the previously disconnected machine and twist the drum by hand.If you heard a metal rattle, and the drum wedged during rotation, it means that something really fell into the tank. A foreign object needs to be urgently pulled out, how to do this is described in detail in the article.The bone from the bra got into the washing machine.

If the Bosch machine refuses to wash and issues the F21 code not because of a breakdown of any part and not because of a foreign object, but because of a strong voltage drop in the mains, then more drastic measures will have to be taken. The fact is that if in the village in which you live there are problems with the power grid and fluctuations occur frequently, you need to protect the washer withvoltage stabilizer. Otherwise, another such difference can burn out all the electronics of the machine and this will definitely send your "home assistant" to the trash.

Summing up, we note that the error with the code F21 on the Bosch washer is quite common and its reasons are varied. We tried to describe the main ones. We hope the information provided will be useful to you. Have a good repair!