Bosch Washer Error Code E04 — What It Means & How to Fix It

What Does This Error Mean?

The E04 error on your Bosch washer means it detected a water leak. Water has reached the base pan underneath the machine. This is a serious error — the washer shuts down immediately to prevent flooding and electrical damage.

Affected Models

Bosch 300 Series
Bosch 500 Series
Bosch 800 Series
Most Bosch front-load washers

Common Causes

A loose or cracked water inlet hose connection at the back of the washer
The door seal (boot gasket) is torn, cracked, or has come loose
The drain pump seal is leaking water into the base pan
An internal hose inside the washer has come loose or split
The detergent dispenser tray is cracked or its hose is disconnected

How to Fix It

Turn off the washer and unplug it from the wall immediately. Then turn off the water supply valves behind the machine.

Safety first. Water and electricity are a dangerous combination.
Pull the washer away from the wall carefully. Check the water inlet hose connections at the back for any dripping or moisture.

Tighten any loose connections by hand. Replace hoses that are cracked or bulging.
Open the door and inspect the rubber door seal all the way around. Look for tears, cracks, or areas where it has pulled away.

Run your finger along the entire seal. Even a small tear can cause a leak.
Tilt the washer back carefully and check the base pan for standing water. Soak it up with towels.

The leak sensor in the base triggers E04 even from a small amount of water.
If you cannot find an external leak source, an internal hose or seal is likely the cause. Call a technician for further diagnosis.

Internal leaks require removing panels and are not safe for DIY repair.

When to Call a Professional

Because E04 involves water near electrical components, it is best handled by a professional. Do not ignore this error or try to bypass it. A technician can safely inspect all internal hoses and seals. Expect repair costs of $150–$400 depending on the source of the leak.

Frequently Asked Questions

Is the E04 error dangerous?

It can be if ignored. Water near electrical parts creates a shock or fire risk. The washer shuts down as a safety measure. Always unplug the machine before investigating.

Can I reset the E04 error and keep using the washer?

You should not ignore a leak error. Even if you dry the base and reset the washer, the leak source is still there. It will happen again and could cause water damage to your floor. Find and fix the leak first.

How does the Bosch washer detect a leak?

Bosch washers have an AquaStop system. There is a float sensor in the base pan under the machine. When water reaches this sensor, it triggers E04 and shuts everything down. This protects your home from flooding.