Bosch F18 Error Code — What It Means
The F18 code (sometimes shown as E18 on certain models) signals a drainage fault. Your washer’s controller has detected that the pump-out phase exceeded the allowed time limit. In practical terms, the machine is not draining fast enough or is not draining at all. Water remains in the drum longer than the program expects, triggering the fault and stopping the cycle.
Common Causes
- Blocked drain filter or coin trap Lint, coins, buttons, hair grips, and other debris accumulate in the filter housing and prevent water flow.
- Kinked or blocked drain hose The hose may be crushed, routed incorrectly, or obstructed internally, restricting water discharge.
- Foreign object in pump impeller Small items lodge in the pump housing or impeller area and prevent the impeller from spinning freely.
- Failed drain pump motor The pump motor itself may be seized, electrically open-circuit, or mechanically worn out.
- Wiring or control circuit fault A loose connector or failed wiring to the drain pump can prevent the controller from running the pump properly.
Step-by-Step Fix
- Isolate power by unplugging the washer or switching off the circuit breaker before any work.
- Drain standing water using the emergency drain hose (usually behind the service flap) or by slowly opening the pump filter area into a shallow pan.
- Remove and clean the drain filter by unscrewing the coin trap cover at the lower front of the machine and pulling out all debris, hair, and foreign objects.
- Inspect the pump impeller by reaching into the filter cavity and rotating the impeller by hand to confirm it spins freely without obstruction.
- Check the drain hose for kinks, crushing, or blockage by disconnecting it at the back of the washer and flushing it with water in a utility sink.
- Test the pump electrically using a multimeter to check for continuity across the pump motor terminals if the mechanical path is clear but the fault persists.
- Reassemble and test by refitting the filter, reconnecting the hose, restoring power, and running a drain or spin cycle to verify the repair and check for leaks.
Parts Often Needed
| Part | Notes |
|---|---|
| Bosch washer drain pump | Amazon | Match by your washer’s E-Nr or model number if the pump is electrically dead, seized, or noisy. |
| Drain hose | Amazon | Replace if the original is split, permanently kinked, or internally clogged beyond flushing. |
When to Call a Pro
Call a technician if you have cleared the filter and hose, verified the impeller spins freely, and the F18 code still appears. Persistent faults after mechanical cleaning usually point to a failed pump motor or a wiring and control board issue that requires diagnostic tools and part-specific troubleshooting. Also call for help if you are uncomfortable draining the machine, accessing the pump area, or working with electrical testing.