Why Is My Bosch Dishwasher Not Cleaning Properly?

You open the door of the dishwasher, and instead of clean and shiny dishes, there are still dirty dishes with food residue and soap stains. Sounds familiar? It is definitely not the best thing, but do not think that your dishwasher is about to break down. It is likely that the problem is caused by trivial reasons that you can eliminate yourself.

Why is my Bosch dishwasher not cleaning properly? The reason why your Bosch dishwasher is not cleaning properly may be the incorrect use of a dishwasher, caused by the food residue stuck in it, incorrect choice of a washing mode, washing at low temperatures (30-40 degrees), overloading of the dishwasher and use of not suitable detergents for washing. Bosch dishwashers may also not clean properly because of the limescale or clogged filters.

Now let’s dive into this to understand and solve this problem.

Why Won’t My Bosch Dishwasher Clean Properly?

Improper use of the Bosch dishwasher:

  • Remains of food and dried food. If you do not remove all this from the dishes, then the washing quality will never be perfect. All manufacturers warn about this rule and it is recommended to follow it.
  • Incorrect mode selection. Economy and short programs are only intended for light soiling, and greasy dishes require the longest cycle at the maximum temperature.
  • Overloading the machine. If the dishwasher does not clean the dishes well, you may be loading too many dishes and other utensils into it. Try putting in fewer dishes next time — chances are your problem will be solved.
  • Incorrect use of detergents. The wrong choice of cleaning chemicals and/or their amount is a common reason why your Bosch dishwasher is not cleaning well. Try to decrease or increase the amount of rinse aid, or even change its brand.
  • Incorrect dishwasher installation. Incorrect installation and connection of the dishwasher can also affect the quality of the wash: for example, the water pressure may be insufficient, or the drain is connected too low.
  • Broken water hardness detector. As a rule, such sensors are installed on expensive models: they monitor salt consumption. The defective sensor will have to be replaced.

If all these manipulations did not lead to a positive result, and your dishwasher still does not wash dishes well, then you will have to look into its internal structure. Some problems appear as a result of regular use of the dishwasher and can well be solved without the involvement of specialists.

Problems with active use of a Bosch dishwasher:

  • Scale. Perhaps this is one of the most insidious enemies of dishwashers. Scale appears due to hard water (even despite the use of special softeners), it is not visible on the plastic parts of the equipment, but inside, where the parts are metal, the scale is slowly doing its job.
    Scale settling on the sprinklers prevents water from spraying, and, as a result, the dishwasher does not wash the dishes well. To eliminate this problem, it is necessary to pour citric acid into the machine instead of the detergent and run it out at the maximum temperature in idle mode.
  • Clogging. The cause of logging is food leftovers, particles of napkins, and other residues that get on the dishes inside the machine. As a rule, filters and sprinklers are most susceptible to this. Therefore, if suddenly your Bosch dishwasher began to wash the dishes poorly after long months of good operation, the first thing to do is check the filters. And continue to clean them after each use of the dishwasher, as recommended by the manufacturers.
    How often does a Bosch dishwasher filter need to be cleaned? Ideally, your Bosch dishwasher filter needs to be cleaned after every washing cycle. If you do not have this opportunity, clean the filters at least once every two weeks.

BOSCH Dishwasher NOT CLEANING — EASY FIX Video Guide

6 Reasons Why Your Bosch Dishwasher Is Not Cleaning Properly and Leaves Residue

ReasonWhat to do
The water heater is out of orderDishwashers are equipped with a water heating device. This element is more susceptible to scale formation than any other, and "burns out" during prolonged use. When the heating element fails, the water does not heat up; therefore, the dishwasher does not wash the dishes well, since most of the dirt cannot be washed off with cold water.

Replacement of heating element is required.
Malfunction in the circulation pumpThe water pump pumps water into the dishwasher. If it fails, then water does not flow to the dishes, respectively, the washing process does not start.

Replacement of the circulation pump is required.
The sprinkler impeller is out of orderAn impeller is a special mechanism that rotates a rocker arm with spray arms. If the impeller breaks down, the sprinklers do not rotate (there may be an interruption in the operation of either one sprinkler or both) and the water does not wash the dishes well.

Impeller replacement required.
Malfunction of the thermal sensor (thermal relay)Thermal sensor - measures the temperature of the water and sends this information to the program module, which gives the command to the heating element for heating. If the information from the thermal sensor does not come, the water does not heat up, and the dishwasher does not wash the dishes well with cold water.

Replacement of the thermal sensor is required.
Failure of the program moduleThe software module sends commands to all technical units of the dishwasher, for example, "heat water", "drain water", "draw water". If the software module fails, the dishwasher starts to work incorrectly or stops working completely.

Module replacement is required.
Malfunction in the water turbidity sensorExpensive dishwasher models are equipped with a turbidity control sensor. Thanks to them, the program module receives information about the state of the water. If it is cloudy, then the dishes are still dirty, and the washing cycle should be continued. When the sensor fails, the software module “does not understand” the current soiling of the dishes, and the dishwasher cannot complete the washing cycle correctly.

The turbidity sensor needs to be replaced.

All these breakdowns can be eliminated only by a qualified technician who has specialized knowledge, experience, and specialized equipment necessary for diagnostics and repair. Attempts to fix the dishwasher yourself can lead to bad consequences.

Problems with detergents.

The next group of reasons why the Bosch dishwasher has become worse at washing dishes is related to detergents. The most common occurrence is the change of dishwashing detergent, such as powder or tablets. But this problem can be easily solved if you wash the dishes again with the detergent that you used previously, or change it to some other option until you find something acceptable and effective.

But if your detergent is fine but the dishwasher still cleans badly, then check the following:

  • If stains appear on the dishes, most likely there is not enough rinse aid. What should be done in this case? It is necessary to change the settings for the supply of the agent, or rather increase it, but not much, because an excess of the agent will lead to the excessive shine of the dishes and its poor rinsing.
  • The reason for the appearance of white streaks on the dishes may be salt that got into the dishwasher tank when pouring it into the dishwasher. It means that the salt compartment lid may not be properly closed.
  • If there are traces of tea, coffee, or lipstick on the cups, then a possible reason may be the lack of bleach in the detergent.
  • Plastic dishes may not be washed due to the low content of a special substance in the detergent.
  • Poor cleaning may be caused by using non-dishwasher detergents. These products may seem effective at first, but over time they will clog the holes in the spray arm, which will reduce the quality of the wash.
  • If you refuse to use special salt, over time, you can also notice that the dishwasher has started cleaning worse. Salt is necessary to restore the ability of the ion exchanger to soften hard water. If the machine is operated for a long time without salt, and the water in the region is hard, then the ion exchanger becomes clogged and may fail altogether.


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