Bosch F27 Error Code — What It Means
The F27 error code on a Bosch washing machine indicates a pressure sensor fault in the water-level sensing system. Bosch advises not to use the washer until the issue is repaired. The pressure sensor monitors water fill levels, and when it fails or receives incorrect readings, the control board throws F27 and halts operation to prevent overfilling or underfilling.
The fault typically involves the pressure sensor itself, the air tube that connects the sensor to the tub, or a blockage or disconnection in that sensing line. Bosch’s official support pages direct customers to contact Bosch Customer Support or schedule a service appointment rather than publish DIY repair steps for this code.
Common Causes
- Faulty pressure sensor or pressure switch The sensor component itself has failed and no longer accurately reads water-level pressure, triggering the F27 fault.
- Kinked, split, or disconnected pressure hose The air tube running from the tub to the sensor is damaged, pinched, or has come loose, preventing correct pressure transmission.
- Blockage in the pressure-sensing line Lint, detergent residue, or debris has clogged the pressure hose or the port at the tub, causing false readings.
- Loose or corroded electrical connector at the sensor The wiring harness plug at the pressure sensor is not seated properly or has corrosion interrupting the signal to the control board.
- Control board or PCB fault If the sensor circuit is verified and the fault persists, the control board itself may have a failure in the pressure-sensing input, though this is less common.
Step-by-Step Fix
- Confirm the F27 code and stop using the washer. Bosch advises not to operate the machine until the fault is repaired to avoid water-fill issues.
- Unplug the washer and shut off water supply. Disconnect electrical power and turn off both hot and cold inlet valves before opening any panels or handling components.
- Access the pressure sensor and pressure hose. Remove the top or rear panel (consult your model’s service manual for location) to locate the pressure switch and the small-diameter air tube running from the tub to the sensor.
- Inspect the pressure hose for damage or blockage. Check the entire length for kinks, splits, disconnections, or obstructions, and blow through it gently to confirm it is clear.
- Check the sensor electrical connection. Unplug and reseat the wiring harness connector at the pressure sensor, looking for bent pins, corrosion, or loose fit.
- Test or replace the pressure sensor. If the hose and wiring are sound, replace the pressure switch with a new unit matching your Bosch model number, or test the existing sensor if you have appropriate diagnostic tools.
- Reassemble and test the washer. Restore panels, reconnect power and water, and run a short cycle to verify that F27 is cleared and normal water-level sensing resumes.
Parts Often Needed
| Part | Notes |
|---|---|
| Bosch pressure sensor (pressure switch) | Amazon | Verify the part number for your specific Bosch washer model before ordering. |
| Pressure hose (air tube) | Amazon | Replacement hose if the original is split, kinked, or cannot be cleared of blockage. |
When to Call a Pro
Call a Bosch-authorized technician if you are uncomfortable removing panels or handling electrical connectors, if the pressure sensor and hose both check out but the F27 fault remains, or if you suspect a control-board issue. Bosch’s official support pages direct customers to contact Bosch Customer Support or book a service appointment for F27, and a qualified technician will have model-specific diagnostics and access to OEM parts and schematics not published for field service.