The E04 code on many Bosch washers signals a drainage problem or excessive suds that prevent the machine from pumping water away. The washer detects slow or blocked drainage and stops the cycle to avoid flooding or continued operation under poor conditions.
What Commonly Causes E04
Clogged pump filter, trapped debris in the sump, a kinked or blocked drain hose, or a failing drain pump. Excess foam from too much or wrong detergent can also trigger the code by slowing water flow. Mechanical faults in the pump or electrical faults in the control board are less common but possible.
Quick Checks You Can Do Right Now
Unplug the washer or switch off its breaker before you touch anything. Look for standing water in the drum. Check the drain hose at the back for kinks or bends. If the machine has a small access cover at the front lower corner, you can open it to reach the pump filter. Prepare towels and a shallow container because water often spills when you open the filter.
Step by step: clear common blockages and reset the machine
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Reset power. Unplug the washer or switch off the breaker for 60 seconds, then restore power and try a drain or spin cycle. Small electronic glitches clear this way.
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Inspect the drain hose. Detach the hose and run water through it to confirm flow. Remove kinks and check the external routing for restrictions.
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Clean the pump filter. Open the front access panel, loosen the filter cap slowly, and catch the water. Remove lint, coins, and small debris from the filter and sump area. Refit the cap securely. Many E04 faults clear after this step.
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Run a drain only cycle. After you clean the filter and hose, run a drain or spin program to check if the washer can pump out water.
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Reduce suds and repeat. If you used a lot of detergent or the wrong type, run a rinse and drain cycle with plain water to flush foam. Use HE detergent and the correct dose going forward.
If The Pump Hums But Does Not Pump
If you hear the pump motor humming when the machine runs but water does not flow, the impeller may be jammed or the pump may be failing. Remove the filter and look for trapped items in the impeller area. If nothing blocks the impeller and the pump still does not turn, the pump likely needs replacement. Testing the pump with a multimeter confirms whether the motor windings have continuity.
When to Call a Technician
Call a professional if you find clear pump failure, if the control board shows error patterns that do not clear with reset, or if you are uncomfortable accessing internal parts. Also call a pro if the problem repeats after you clean the filter, since recurring E04 often points to a damaged pump, internal blockage in hoses, or electronic faults.
Prevent the E04 Error from Returning
Use the correct high efficiency detergent and measure doses carefully. Empty pockets and remove debris before washing. Clean the pump filter monthly and inspect the drain hose for kinks. Run a regular maintenance wash on hot with a washer cleaner or two cups of white vinegar to clear residues and reduce foam buildup.
Safety and Final Notes
Always disconnect power before opening panels or handling electrical components. If you must remove the pump or replace parts, follow model specific instructions or hire a certified technician. Proper diagnosis saves time and prevents further damage.
