Bosch Dishwasher Drain Pump Test

Bosch dishwashers are known for their reliability and efficiency in cleaning dishes. However, like any other appliance, they can encounter issues over time. One common problem that users may face is a malfunctioning drain pump. The drain pump is responsible for removing water from the dishwasher after a wash cycle. If it fails to work correctly, it can lead to standing water in the dishwasher. In this guide, we will walk you through the steps to test the drain pump in your Bosch dishwasher.

Tools and Materials


1.1. Open the dishwasher door and remove the bottom rack to access the dishwasher’s interior.

1.2. Depending on the model of your Bosch dishwasher, you may need to remove the lower kick panel or the entire front panel to access the drain pump. Use a screwdriver to remove any screws securing these panels.

2. Disconnecting the Drain Pump

2.1. Locate the drain pump. It’s usually at the bottom of the dishwasher near the back.

2.2. Carefully disconnect the wires from the drain pump. Be sure to remember which wire goes where for reassembly.

2.3. Disconnect any hoses attached to the pump. Be prepared for some water to spill out, so have towels and a bucket ready.

3. Testing for Continuity

3.1. Set your multimeter to the continuity or ohms setting.

3.2. Place the multimeter probes on the terminals of the drain pump. If the multimeter beeps or shows a low resistance reading, it means there is continuity, indicating that the pump’s electrical circuit is complete.

3.3. If the multimeter does not beep and shows no continuity, it suggests a problem with the drain pump, and it may need to be replaced.

4. Reassembly

4.1. If the drain pump tested positively for continuity, reconnect the wires and hoses to the pump.

4.2. Reattach any panels or covers that were removed to access the pump.

5. Power Up and Test

5.1. Reconnect the dishwasher to the power source and turn it on.

5.2. Run a short wash cycle and monitor whether the drain pump operates as expected. You should hear the pump working to remove water from the dishwasher.

5.3. If the pump still doesn’t work, it may require professional repair or replacement.

6. Checking for Blockages

6.1. Before you test the drain pump, it’s wise to check for any blockages that might be causing drainage problems. Sometimes, debris like food particles, paper, or small objects can obstruct the pump or drain hose.

6.2. To inspect for blockages, remove the dishwasher’s filter and any debris trapped in the sump area. Ensure the drain hose is clear as well. A blocked hose or pump could mimic a faulty drain pump.

6.3. Clear any blockages you find and then reassemble the dishwasher. Test it again to see if the issue is resolved.

7. Testing the Impeller

7.1. The drain pump typically has an impeller inside that helps move water. Sometimes, the impeller can become jammed or damaged.

7.2. To test the impeller, manually rotate it with a screwdriver or your finger. It should move freely without any obstruction. If it’s stuck or difficult to turn, it may need to be replaced.

8. Replacing the Drain Pump

8.1. If your tests confirm that the drain pump is faulty and needs replacement, you’ll need to order a new pump that’s compatible with your Bosch dishwasher model.

8.2. Follow the manufacturer’s instructions for replacing the pump carefully. It often involves removing the dishwasher from its installation location and tipping it on its back to access the pump from underneath.

8.3. Disconnect the old pump, and connect the new one following the same wire and hose connections.

8.4. After replacing the pump, reassemble the dishwasher, restore power, and run a test cycle to ensure the new pump is working correctly.

9. Preventative Maintenance

9.1. To avoid future drain pump issues, consider practicing preventative maintenance. This includes regularly cleaning the dishwasher’s filter, checking for debris, and ensuring the drain hose is not kinked or obstructed.

9.2. Use high-quality dishwasher detergent and avoid overloading the dishwasher, as excessive food debris can lead to clogs.

10. Professional Assistance

10.1. If you are uncomfortable or unsure about any aspect of testing or replacing the drain pump, or if you have followed these steps and still experience drainage issues, it’s best to contact a certified Bosch appliance technician. They have the expertise and tools to diagnose and fix more complex problems.

Bosch Dishwasher Drain Pump Test

Test IDTest ObjectiveTest EquipmentProcedureResults
1Pump functionalityMultimeterConnect multimeter to pump terminals. Run dishwasher cycle. Check voltage and continuity.Voltage: 120V, Continuity: OK
2Pump noise levelSound level meterPlace meter near running dishwasher. Record and analyze pump noise during different cycles.Avg. noise: 45 dB
3Pump efficiencyFlow rate measurementMeasure water flow rate with pump running. Calculate gallons per minute.Flow rate: 2.5 GPM
4Pump leakageVisual inspectionRun dishwasher. Check for any visible water leakage around the pump area.No leakage observed
5Pump blockagePressure gaugeInsert pressure gauge into pump inlet. Run cycle. Observe pressure changes indicating blockage.Pressure increase: 5 psi
6Pump motor currentAmmeterConnect ammeter to pump circuit. Run dishwasher. Measure and record pump motor current.Current: 0.8 A
7Pump thermal performanceTemperature sensorMonitor pump temperature during extended operation. Check for overheating.Max temp: 60°C
8Pump cycle durationStopwatchRecord time taken for pump to complete a full cycle. Compare with standard cycle duration.Cycle time: 45 minutes
9Pump vibrationVibration sensorAttach vibration sensor to pump housing. Run dishwasher and monitor vibration levels.Vibration intensity: Low
10Pump longevityRun-time testOperate dishwasher continuously for an extended period to assess pump longevity.Pump remains operational


Testing the drain pump in your Bosch dishwasher is a straightforward process that can help diagnose issues with water drainage. By following these steps and taking appropriate safety precautions, you can determine whether the drain pump is functioning correctly or if it needs further attention from a technician or replacement. Remember that if you are uncomfortable performing these tests, it’s always best to consult a professional appliance repair service.


Bosch Dishwasher Drain Pump Test

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