Bosch dishwashers with electronic controls include a self-test program that can run the main components in sequence. It is useful when you want to confirm whether the machine fills, washes, heats, and drains before deciding if a service call is needed.
This guide covers many Bosch 300, 500, and 800 series dishwashers sold in the US with touch or electronic controls.
Does this affect you?
Diagnostic mode is different from a normal wash cycle. It is designed to step through core systems so you can observe what works and what fails. A technician may use the same kind of test at the start of a repair visit.
Start the self-test program
The exact buttons vary by Bosch series and control-panel generation, but the process is generally the same.
- Empty the dishwasher and clean the bottom filter so water movement is easier to see.
- Close the door completely.
- Press and hold the self-test button combination for your model. On many Bosch models this is two program buttons held together for three to five seconds, but the exact pair must be confirmed in the model manual or service sheet.
- When the display responds, let the dishwasher move through fill, wash pump, heating, and drain stages automatically.
- Watch and listen at every stage. You are checking for water entering without leaks, spray-arm movement or pump sound, heat during the heating stage, and complete draining at the end.
- Most self-tests finish in under 10 minutes. If the test completes without a displayed fault, the main components passed that check.
The test uses water, pumps, and heat. If you open the door to stop the program, open it carefully and do not put your hands into the tub right away because water and interior surfaces may be hot. Do not remove panels, touch wiring, or bypass door switches.
Read the result and match it to an error code
If the dishwasher shows a fault during diagnostic mode, use the exact code as your next step.
- Write down the code exactly as shown, such as E15, E24, or another letter-number combination. Some models clear the display after the door opens.
- Check the code against your specific Bosch manual or Bosch support page. Similar-looking codes can point to different systems by model.
- Common examples include leak-sensor faults and drain faults, but heating, water inlet, and control issues have their own model-specific codes.
- If no code appears but one stage obviously fails, such as no fill sound or standing water after drain, troubleshoot that stage even without a stored fault.
- To exit, open the door or cancel according to the model instructions.
A Bosch self-test checks whether components operate. It does not judge cleaning quality. If dishes are dirty but the diagnostic program passes, look at clogged spray arms, a dirty filter, hard-water scale, detergent use, loading, or low incoming water temperature.
If you clear a code and it immediately returns during diagnostic mode or the next normal cycle, treat that as confirmed. Repeating the reset will not fix a failed valve, pump, heater, sensor, or control board.
Call a technician when the code involves the heating circuit, water valve, main control board, or anything you cannot safely reach from normal user-accessible areas, especially if the dishwasher is still covered by Bosch warranty.
Sources
- Bosch Home Appliances – Dishwasher Self-Diagnosis Guide (2025)
- Bosch Home Appliances – Error Codes and Troubleshooting (2025)
- Bosch Service – Test Program Instructions (2024)