Bosch NEXXT front-load washer Error Code Er:21: Meaning & How to Fix It

By the ErrorCodePro Editorial Team · Last reviewed October 20, 2026

Bosch NEXXT front-load washer error code Er:21 means: Excessive foam detected. [1] Keep using it? Only if the owner checks below clear the code; if it returns, stop and book a repair. Start with the owner checks below, beginning with: write down the code and model number.

Source: Bosch NEXXT front-load washer error-code chart, via Sears PartsDirect [1].

Quick facts

Code	Er:21
Also shown as	None listed by the manufacturer
Brand / appliance	Bosch NEXXT front-load washer
System	Control / electronics
Meaning (service chart)	Excessive foam detected. [1]
Keep using it?	Only if the owner checks below clear the code; if it returns, stop and book a repair
DIY-safe?	Owner checks only (listed below)
Support	Bosch Customer Support: 1-800-944-2904
Source document	Bosch NEXXT front-load washer error-code chart (via Sears PartsDirect)

On this page: Meaning · Steps · Parts · When to call a technician · Related codes · FAQ

What error code Er:21 means on a Bosch NEXXT front-load washer

Excessive foam detected. [1]

This is a control / electronics code. Codes and wording can vary by model, so check your owner's manual for your model number.

How to fix Bosch NEXXT front-load washer error code Er:21 (safe owner checks)

Safety first: disconnect power before you remove any panel or reach into the sump or drum. Do not touch wiring, the control board or the motor. If you see water near electrical parts, stop and call a technician. These steps are based on the Bosch NEXXT front-load washer error-code chart (via Sears PartsDirect) [1], rewritten for clarity.

Write down the code and model number. Note exactly what the display shows (Er:21) and copy the full model number from the rating label, so you can confirm this chart applies to your NEXXT front-load washer and order the right parts.
Fix the detergent dose. Use the proper amount of high-efficiency (HE) detergent in the washer.
Do a power reset. Unplug the appliance or switch off its breaker for one minute, then restore power and try again. If the code clears and stays away, it may have been a one-off fault.
Test and decide. Run a short cycle or restart and watch the display. If Er:21 comes back after these checks, stop using the washer for this function and call a technician, because the remaining causes need meters or part replacement.

The first and last steps (and the power reset) are general owner checks added by ErrorCodePro; the rest follow the Bosch NEXXT front-load washer error-code chart published by Sears PartsDirect, rewritten for safe owner use.

Parts that may be involved

Exact parts depend on your model number. This page lists part types only, never part numbers.

HE detergent

When to call a technician

Anything involving wiring, the control board, the motor or the water valve electrics
The appliance is under warranty: contact Bosch Customer Support: 1-800-944-2904 first

Frequently asked questions

What does error code Er:21 mean on a Bosch NEXXT front-load washer?

The Bosch NEXXT front-load washer error-code chart lists Er:21 as follows: Excessive foam detected.

Is it safe to keep using the NEXXT front-load washer with Er:21?

Only if the owner checks below clear the code; if it returns, stop and book a repair.

Can I fix Bosch NEXXT front-load washer error Er:21 myself?

Only with the owner checks on this page, starting with: write down the code and model number. If it persists, call a technician or Bosch Customer Support: 1-800-944-2904.

Sources

Sears PartsDirect: Bosch NEXXT front-load washer error-code chart (third-party copy of manufacturer service data)

Last reviewed: October 20, 2026. ErrorCodePro is not affiliated with Bosch.