How can I fix a Bosch dishwasher running with door open or not starting?

If your Bosch dishwasher runs with the door open, won’t start, or behaves randomly, you’re dealing with a safety or sensor issue. These machines are designed to stop instantly when the door opens, so unusual behavior usually points to a fault.

Let’s break it down in a simple, real-user way.

Quick Answer

This problem is most often caused by a triggered flood switch (water in base pan), faulty water inlet valve, or sensor/control board issue. Start by checking for water underneath the unit.

Step-by-step fix for Bosch dishwasher acting oddly

Step 1: Check for water in the base pan (very important)

This is the #1 cause.

• Turn off power
• Remove the bottom kick plate
• Look for water in the base tray

👉 If water is present, the flood switch is triggered, forcing the drain pump to run constantly

Step 2: Dry the base and reset

If water is found:

• Use towels or cloths to dry it completely
• Let it sit for a while
• Restore power

👉 Once dry, the dishwasher should reset and behave normally.

Step 3: Understand the drain behavior

If it keeps draining even with the door open:

• That’s not a bug
• It’s a safety feature triggered by the flood switch

👉 The machine is trying to prevent overflow damage

Step 4: Check the water inlet valve

If the dishwasher fills when it shouldn’t:

• Turn off water supply
• Observe if water still enters

👉 If it does, the inlet valve is faulty and must be replaced.

Step 5: Inspect sensors (E6 / water sensor issues)

If you see errors like E6:

• This relates to turbidity or water sensor
• Dirty or faulty sensors can stop the machine

👉 Sensor issues can make the dishwasher act like the door is open

Step 6: Check for buildup in water inlet system

On the left side of many Bosch units:

• Remove and inspect the inlet housing
• Clean sediment or debris

👉 Blockages here can cause strange noises and errors.

Step 7: Verify door switch (but don’t assume it’s the cause)

Even if symptoms point to it:

• Test with a multimeter
• Ensure proper connection

👉 In many cases, the door switch is fine - the issue is elsewhere.

Step 8: Consider control board only after everything else

If all checks pass:

• Control board may be faulty
• Especially if voltage behaves incorrectly

👉 This is usually the last step due to cost.

Extra tips and best practices

• Always fix leaks immediately to avoid triggering flood switch
• Clean filters and inlet systems regularly
• Avoid running dishwasher with blocked drains
• Ensure proper installation and leveling

Common mistakes to avoid

• Replacing the door switch too quickly
• Ignoring water in the base tray
• Overlooking inlet valve faults
• Jumping straight to control board replacement

FAQ

Why does my dishwasher run even when the door is open?

Because the flood switch is triggered, forcing the drain pump to run as a safety feature.

Why won’t my dishwasher start at all?

It may think there’s an error condition (sensor, water, or safety issue) and refuses to run.

Can a bad inlet valve cause overflowing?

Yes. A faulty valve can allow water in even when it shouldn’t.

Conclusion

If your Bosch dishwasher runs with the door open or won’t start, begin with the basics: check for water in the base pan and inspect the inlet system.

Most cases are caused by flood protection activation or water flow issues, not the door switch. Fix the root cause, and the dishwasher should return to normal operation.

Reference links

https://www.bosch-home.com/us/support
https://www.repairclinic.com/RepairHelp/Dishwasher-Repair-Help