Bosch E21 Code: Wash Motor Running Slow or Stuck

Quick Answer

Bosch E21 means the motor started but could not reach full speed. Check the sump for debris first - broken glass from glassware is the most overlooked cause and takes 5 minutes to find. Remove the filters, use a flashlight, and look carefully around the impeller inlet. If the sump is clear and you hear a grinding or rumbling noise during the wash cycle, the motor bearings are worn and the motor assembly needs replacing.

E21 means the wash motor started but could not reach its target speed - this is different from E20 where the motor never starts at all. The most common cause is physical debris in the sump jamming the impeller. Broken glass is a surprisingly common culprit, particularly after washing glassware. If the sump is clear, worn motor bearings are the next suspect. A grinding or rumbling noise accompanying E21 is a reliable indicator of bearing failure. Bosch, Siemens, and Thermador dishwashers share most error codes as all three are manufactured by BSH Group. The same fixes generally apply to Siemens and Thermador units.

BoschDishwasherSeverity: moderateDifficulty: intermediate70% DIY Success

Time to Fix

45–180 min

Difficulty

intermediate

Parts Cost

$120 – $260

Tools Needed

Flashlight, Needle-nose pliers

Wrong code?

Not seeing E21 on your display?

Select what your appliance is actually doing and we'll take you to the right guide.

Motor fails to start or reach RPM

E20

Motor electrical fault detected during run

E01

Water not draining from tub

E24

What Does the E21 Code Mean?

Something might be physically blocking the wash motor, or the motor is wearing out. The good news is that a debris blockage is a free fix. The bad news is that bearing failure means motor replacement.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Foreign object or debris in the sump area jamming the impeller40%

Broken glass fragments lodged around the motor intake24%

Worn motor bearings causing drag and preventing full-speed operation14%

Partial mineral scale buildup around impeller in hard-water areas12%

Damaged impeller vane reducing pumping efficiency10%

Symptoms You May Notice

Dishwasher runs but wash action sounds weak or labored
Grinding or rumbling noise during wash cycle
Dishes not getting clean despite full cycle running
E21 code appears mid-cycle after motor starts
Spray arms moving slower than normal or intermittently stopping

Can you reset a Bosch dishwasher to clear the E21 code?

After clearing debris from the sump, reset the dishwasher by holding Start/Reset for 5 seconds with the door open, then close the door to allow a drain cycle. If E21 was caused by debris, the code should not return. If it returns after the fix, proceed to motor bearing diagnosis.

Tools Required for Diagnosis

FlashlightNeedle-nose pliersFlat-head screwdriverTorx T20 screwdriverWork gloves (for glass removal)

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

Check the sump area for debris and glass

Remove the lower rack and pull out the filter assembly - twist the cylindrical fine filter counterclockwise, then lift out the flat mesh filter underneath it. Use a flashlight to inspect the sump cavity thoroughly. Look specifically for: broken glass fragments (these are easy to miss, especially small shards), food debris compacted around the drain opening, small plastic pieces from broken utensils or items that fell off the rack, and any foreign objects like bottle caps or twist ties. Remove any debris you find using needle-nose pliers. Do not reach in bare-handed if glass is suspected. After clearing debris, reinstall the filter and run a short rinse cycle to see if E21 clears.

Manually rotate the impeller for resistance

Inspect spray arm bearings for drag

Run the motor and listen for bearing noise

Replacement Parts

If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.

Part Name	OEM Number	Estimated Price
Wash motor and circulation pump assembly00654575 · $120–$260	00654575	$120 – $260

Verify part fitment for your Bosch model

Repair vs. Replace Calculator

Appliance Age (Years)7 Yrs

Labor Approach

Our Verdict

BORDERLINE

Estimated Cost: $190 (Parts) vs $650 (New Machine)

Frequently Asked Questions

Can broken glass in the sump cause Bosch E21?

Yes, this is one of the most common causes of E21 and one that many people overlook. A single glass chip or shard lodged around the motor impeller creates enough drag to prevent the motor from reaching target speed. Always use gloves when inspecting the sump if glassware has broken in the dishwasher. Use a flashlight and check carefully because small glass fragments are hard to see. Remove all fragments before testing again.

My Bosch is showing E21 and making a grinding noise - what does that mean?

Grinding noise with E21 is a strong indicator of motor bearing failure. The bearings inside the circulation pump motor wear over time, especially in hard-water areas where mineral deposits work into the bearing race. Once you hear grinding, the motor is on its way out. The bearings are not replaceable separately in Bosch circulation pumps, so motor replacement is the repair. The machine will usually still run intermittently until the bearing fully seizes.

Will cleaning the dishwasher filter fix E21?

Cleaning the filter can fix E21 if debris accumulation around the sump was creating load on the impeller. Remove the filter, clean it thoroughly under running water with a soft brush, and also inspect and clean the sump cavity below the filter. If the filter was extremely clogged and restricting flow, clearing it may resolve the code. However, if the motor bearings are worn, filter cleaning will not help. It is always the right first step because it is free and quick.

What are the symptoms of motor bearing failure on a Bosch dishwasher?

Worn motor bearings typically present with a low rumbling or grinding sound during the wash phase that gets louder over several weeks, E21 codes appearing mid-cycle as the motor struggles to maintain speed, gradually worsening cleaning performance, and eventually complete motor seizure triggering E20. The progression from early bearing noise to full failure can take anywhere from a few weeks to several months depending on how heavily the machine is used.

What is the difference between E21 and E20 on a Bosch dishwasher?

E20 means the motor failed to start at all - zero RPM detected when the control board expected movement. E21 means the motor started but could not reach its target speed. Think of E21 as a motor that is working but struggling, and E20 as a motor that gave up completely. E21 is more likely to be caused by a physical blockage or worn bearings. E20 is more likely to be a complete motor failure or (on older models) a failed start capacitor.

Related Bosch Dishwasher Error Codes

Code: E20Bosch E20 Error: Wash Motor Not Starting Up Code: E01Bosch E01 Error: Wash Motor Electrical Fault Code: E24Bosch E24 Error: Drain Blocked or Not Draining

Same Fix Works on These Brands

Bosch shares the same hardware platform with these brands. The diagnosis and repair steps are identical.

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Models Known to Experience E21 Errors

This repair applies to most Bosch dishwashers with this error code. Common model numbers include:

SHPM88Z75N, SHPM88Z55N, SHPK7ZL55N, SHEM63W55N, SHPM65Z55N, SHE3AR75UC, SHDF78Z55N, SHEM78ZH5N, SHPM98Z75N

Last verified for technical accuracy on March 14, 2026