Bosch Washer Won't Drain: How to Troubleshoot
A Bosch washer that ends a cycle with water still in the drum, frequently showing E18, has a blocked or failed drain path. Bosch puts the debris filter behind a small front flap, which makes the first and most common fix easy; the whole diagnosis runs about 20-40 minutes.
E18 means the machine could not pump the water out within its time window. On a Bosch that most often traces to the front-access drain filter catching coins, lint, or a stray sock, but it can also be a jammed pump impeller, a drain hose set too high, or a dead pump motor. Because the filter is right up front, you start there and work inward only if it comes up clean.
There is a reason Bosch made that front filter so easy to reach: it is meant to be cleaned as routine maintenance, and a household that never opens it is almost guaranteed an E18 eventually. Coins, buttons, hairpins, and lint all collect there, and a filter packed solid chokes the drain long before the pump itself wears out. Treat the filter check as the default first move on any Bosch drain complaint, and keep a shallow pan ready, because the trapped drum water always comes out with it.
Tools and parts#
Have a flathead screwdriver, pliers, a shallow pan, towels, a flashlight, and a multimeter if you plan to test the motor. Parts depend on the diagnosis — a drain pump such as BSH 00145787 only if the pump proves dead.
Do You Have the Right Tools?
Bearing puller set ($120), drum spider wrench ($85), multimeter ($85), and diagnostic software. Our technician arrives with $3,000+ in professional tools — your diagnostic is free.
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Safety#
Disconnect power. Water is trapped in the tub — drain through the filter before investigating further.
Diagnose the drain#
- Drain the residual water. Open the lower front flap, set the shallow pan and towels beneath it, and let the drum water run out through the filter drain hose before you unscrew anything — a full tub will flood the floor otherwise.
- Inspect the drain filter. Twist the filter out and clear it of coins, lint, hair, and debris. Check the empty filter housing too, and reach in to feel for anything lodged past it. Most E18 faults end at this step.
- Check the pump impeller. With the filter out, look into the pump housing and turn the impeller by hand; it should spin freely. A shard of glass or a wrapped thread jamming the vanes stops the drain even with a clean filter.
- Check the drain hose. Trace the hose from the machine to the standpipe for a kink or a clog, and confirm it is not looped higher than Bosch specifies — a hose set too tall lets water fall back and defeats the pump.
- Test the pump motor. With power off, meter the pump winding across its terminals; an open or shorted reading condemns the pump, while a healthy winding sends you to the wiring or control.
- Check the control-board signal (advanced). If the pump tests good yet never runs, look for the drive voltage — around 240V on many Bosch drains — reaching the pump connector during the drain step; its absence points at the harness or board rather than the pump.
Safety First — Know the Risks
High-voltage components and pressurized water lines create flood and shock risk. A single loose fitting can cause thousands in water damage. Our techs are licensed and insured — let them handle the risk.
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When to call a pro#
If the filter, impeller, and hose are clear and the pump tests good yet the machine still will not drain, the control board or wiring is driving the fault and is best diagnosed by a technician. Repeated impeller jams also hint at a tub problem shedding debris that is worth a professional look.
Appliance Repair Technician · 11 years experience
Experienced technician with 11 years specializing in Frigidaire and Electrolux refrigerator and dryer repair with a focus on safety.
