Bosch Washer Error Codes — E01, E03, E17, E18, E23, E27 & F-Code Repair Guide

Common Symptoms

• Error code E01, E03, E04, E13, E17, E18, E23, or E27 on the display panel
• F-code (F01–F43) displayed — control board or sensor fault on newer models
• Door won't open after cycle completes — Bosch door lock stuck after E01
• Standing water in drum at end of cycle — E03 or E23
• Washer fills slowly or not at all — E17 or E18
• Cycle stops mid-wash with error code and locked drum

Most Likely Causes

1. 1

   E03 — Drain Pump Filter Blocked (Most Common Bosch Fault)

   E03 means the drain pump ran for 3 minutes without successfully draining the drum. On Bosch front-loaders, the drain pump filter is located behind the bottom-front access panel (snap-off or held by 1–2 screws at the lower left of the machine). The filter is a clockwise-lock design — turn it counterclockwise to remove. Coins, bra underwires, lint compacted into a solid mass, and hair are the most common blockages. Remove the filter, clean it and the housing, check the impeller behind the filter cavity for obstructions, and reinstall. Always place a shallow pan under the filter before opening — up to 2 liters of water will drain out.

2. 2

   E01 — Door Lock Fault (Interlock Failure)

   E01 means the door failed to lock at the start of a cycle, or the lock position sensor did not confirm lock. On Bosch, the door lock (interlock) is a known failure component on older 500 series units — the wax motor thermal actuator degrades over time. After E01 is thrown, the door lock can stick in the locked position, trapping laundry inside. Bosch provides a manual door release: reach behind the kick panel (remove the kick panel at the bottom front) and pull the orange or white release cord downward — this mechanically retracts the lock bolt. The lock assembly itself is accessible from inside the door boot gasket after removing the clamp.

3. 3

   E17 — Slow Water Inlet Fill

   E17 means the washer is filling with water, but the fill rate is below the expected minimum — fill took longer than the timeout allows. Common causes: kinked or restricted supply hose, partially closed water supply valve, clogged inlet screen filter (where the hose threads onto the inlet valve), or low water pressure at the tap. On Bosch models equipped with AquaStop hose (integrated pressure sensor hose): a kinked or old AquaStop hose can restrict flow internally even with the external supply fully open. Unthread the inlet hose from the back of the machine and inspect the inlet screen — a small mesh screen sits inside the valve inlet port and traps sediment. Clean it with a toothbrush under running water.

4. 4

   E18 — Water Inlet Valve Fault

   E18 indicates the water inlet valve did not respond correctly to the fill command — either it did not open (no water flowing) or did not close (overflow risk). Test the inlet valve: unplug the washer and disconnect the wiring harness from the inlet valve. Measure solenoid resistance across each solenoid coil terminal — functional solenoids typically read 200–500Ω. OL (open) means the coil has burned out — replace the valve. Bosch inlet valves are specific to the model series — part numbers vary between 500 and 800 series. The Bosch AquaStop inlet hose connects to the valve with a quick-release fitting; if the hose has a damaged pressure sensor, the AquaStop system itself can prevent water from flowing.

5. 5

   E23 — Drain Pump Failure

   E23 means the drain pump motor has failed outright — as opposed to E03, which indicates the pump is running but the filter is blocked. E23 typically means the pump motor winding has burned out or the pump impeller is seized. With the filter clear and no blockage in the drain hose, if E23 persists, the pump motor needs replacement. Bosch drain pumps are a complete assembly — replace the full pump unit. Access is through the bottom front panel. Unplug the machine, remove the filter, disconnect the hose clamps on the pump body, and disconnect the wiring harness. Part number varies by model (check the serial number plate inside the door) — search by model for exact fitment.

6. 6

   E27 — Voltage Fluctuation / Low Voltage

   E27 indicates the machine detected a significant voltage fluctuation or brownout during the cycle. Bosch washers are more sensitive to power quality than American brands — they operate on tighter voltage tolerances. E27 typically clears on its own after a power reset. If E27 appears regularly, have an electrician check the outlet voltage (should be stable 120V ±5%), verify the outlet is on a dedicated circuit, and inspect the power cord for damage. Repeated E27 without a power issue may indicate a failing main control board.

7. 7

   F01–F43 — Control Board / Sensor Electronic Faults (Newer Models)

   Bosch newer front-load models (WAW325H0UC, WGB142000US, WAWH8660UC) use F-prefix codes for electronic faults on the main board and component sensors. Common F-codes: F01 = main board fault; F02 = motor fault; F04 = pressure sensor fault; F21 = motor speed fault; F22 = motor controller; F43 = motor communication fault. Most F-codes require the tech sheet (available on Bosch's website by model number) for exact diagnosis. Some F-codes clear after a power cycle (unplug 60 seconds). Persistent F-codes after a reset indicate board or sensor replacement is needed.

Quick DIY Checks

1. 1Write down the exact error code and attempt a fault clear: On Bosch 500/800 series front-load models, press and hold the Start button for 5 seconds to clear the stored fault on most models (check your tech sheet for the exact clear procedure for your series). If the code clears and does not return within 2–3 cycles, the fault was intermittent. If the same code returns immediately or within the first cycle, the root cause is still present and must be diagnosed. Always record the code before clearing — once cleared, some models reset the display and the code is gone.
2. 2E03 — clear the drain pump filter: locate the bottom-front access panel (lower left of the machine, snap-off or held by 1–2 screws). Place a shallow pan or old towels under the panel before opening — up to 2 liters of water will drain. Remove the small drain hose cap (if present) to drain the standing water before unscrewing the main filter cap. Turn the filter counterclockwise to remove. Remove all debris — coins, lint, underwires. Reach into the pump housing with a finger to confirm the impeller spins freely. Reinsert and turn clockwise to lock. Run a short spin cycle — if it drains cleanly, the fix is complete.
3. 3E01 — unlock the door if stuck: if the door is locked after E01, reach behind the bottom kick panel. Remove the kick panel (2 screws or snap-fit at the front bottom of the machine). Look for an orange or white release cord hanging near the door lock mechanism at the door side. Pull the cord firmly downward — this mechanically retracts the door lock bolt and allows the door to open. Then inspect the door lock assembly: unplug the machine, peel back the door boot gasket and release the spring clamp to access the lock body. Inspect the wax motor actuator — if the body feels soft or the actuator is stuck in the extended position, the lock assembly needs replacement.

1. 4E17 / E18 — check inlet water supply and inlet screen: turn off the water supply valves behind the washer. Unthread the hot and cold inlet hoses from the back of the machine. Inside each inlet port on the valve body, there is a small mesh screen filter. Inspect these screens for mineral scale or debris — clean with a toothbrush under running water. Reattach the hoses (hand-tight plus 1/4 turn) and fully open both supply valves. For E18 (valve fault), unplug the machine, disconnect the wiring harness from the inlet valve, and test each solenoid coil for resistance — expected 200–500Ω. OL = failed coil, replace the valve assembly.
2. 5AquaStop hose inspection (E17 / E18 context): on models with the Bosch AquaStop inlet hose (a thicker, double-walled hose with a pressure sensor housing at the machine end), inspect the hose for kinks, crimps, or age-related stiffening. AquaStop hoses older than 10 years should be replaced regardless of visible condition — the internal pressure sensor can degrade and restrict flow or trigger a false AquaStop shutoff. Replacement Bosch AquaStop hoses are available from Bosch parts directly or from appliance parts suppliers — confirm the thread size and connection type for your model.
3. 6i-Dos automatic detergent check (higher-end models with i-Dos): on Bosch 800 series models with i-Dos automatic dosing (WAWH8660UC and similar), the i-Dos system can generate wash cycle errors if the detergent container is empty, the i-Dos nozzle is clogged, or the dosing pump has failed. Check the i-Dos detergent level indicator on the display. If the container is low, refill with Bosch-specified liquid detergent. If the nozzle at the drum inlet appears clogged (white residue), clean it with warm water. An i-Dos fault can also appear as an E-code on the display — consult the model-specific manual for i-Dos error codes.
4. 7F-code persistent after power reset — identify the component: for persistent F-codes (F01, F02, F04, F21, F22, F43) that do not clear after a 60-second unplug, pull the model-specific tech sheet from Bosch's website (bosch-home.com/us, enter model number, select manuals). The tech sheet maps F-codes to specific sensors and board sections. For F01 (main board) and F02 (motor fault), contact Bosch service or an authorized appliance tech — board-level diagnosis requires Bosch-specific diagnostic tools on newer models. For F04 (pressure sensor), locate the pressure hose on the side of the drum tub, check for kinks or blockages, and test the sensor by blowing gently into the hose fitting.

Repair vs Replace

Recommended Tools & Parts

• Bosch Drain Pump Filter (Access Panel Kit)

  Replacement drain pump filter for Bosch 500/800 series front-load washers. The clockwise-lock filter traps lint, coins, and debris. Should be cleaned monthly on heavy-use machines. Includes filter cap and seal. Verify fitment by model number.

  $15–$30

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• Bosch Door Lock Interlock Assembly

  Replacement door lock mechanism for Bosch front-load washers. Fixes E01 error code. Includes wax motor actuator, latch, and mounting hardware. Access via door boot gasket spring clamp. Verify part number against model — varies between 500 and 800 series.

  $30–$70

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• Bosch AquaStop Inlet Hose

  Replacement AquaStop water inlet hose with integrated pressure sensor for Bosch washers. Prevents flooding if the hose bursts. Replace every 10 years regardless of condition. Fixes E17 restricted flow and false AquaStop shutoff. Available in 5-foot and 7-foot lengths.

  $25–$60

  Buy on Amazon →

• Bosch Water Inlet Valve

  Replacement dual-solenoid water inlet valve for Bosch front-load washers. Fixes E18 inlet valve fault. Test solenoid resistance (200–500Ω each) before ordering. Model-specific — verify with your serial number plate inside the door.

  $40–$85

  Buy on Amazon →

• Bosch Drain Pump Motor Assembly

  Replacement drain pump motor assembly for Bosch washers. Fixes E23 pump failure (as opposed to E03 filter blockage). Complete assembly includes pump body, motor, and mounting hardware. Access via bottom front panel after filter removal.

  $60–$120

  Buy on Amazon →

Links are Amazon affiliate links (tag: fixitfastai-20). Prices are estimates.

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