Bosch Washing Machine
Error Codes — Complete Guide 2026
Bosch washer just threw a code and stopped? I've fixed hundreds of Bosch machines over the years — and the good news is that most of these errors are either straightforward DIY fixes or quick resets. This guide covers every Bosch washing machine error and fault code, with honest advice on what you can fix yourself and when it's time to call a pro.
Table of Contents
Bosch washing machines have been around since the early 1900s, and their engineering quality is genuinely hard to argue with. The error code system they use today is logical and fairly consistent across their front load lineup — all codes start with either E or F, followed by two digits. In practice, E and F codes for the same number usually refer to the same fault depending on the model generation, so I treat them interchangeably throughout this guide.
From what I've seen in the field, the three codes that account for easily 60% of all Bosch service calls are E18 (drain), E16 (door), and E17 (water supply). All three are usually DIY-solvable with a bit of patience. The other 40% — motor faults, sensor failures, PCB issues — those generally need professional diagnosis before you start ordering parts.
One important thing to know about Bosch washers: they don't have a physical reset button. The reset is done by holding the start button for 3–5 seconds or by unplugging for a few minutes. I'll mention this throughout where relevant.
🔍 Top 10 Most Searched Bosch Washer Error Codes (2026)
These are the Bosch washing machine fault codes searched most worldwide right now. Chances are yours is on this list — and most of them have a DIY fix.
| # | Code | Problem | DIY? | Search Volume |
|---|---|---|---|---|
| 1 | E18 / F18 | Drain pump blocked / drainage failure | ✅ Usually | |
| 2 | E16 / F16 | Door not locked / door open | ✅ Often | |
| 3 | E17 / F17 | Water not filling / inlet fault | ✅ Usually | |
| 4 | E23 / F23 | AquaStop activated / leak detected | ⚠️ Partial | |
| 5 | E19 / F19 | Heating element / temperature failure | ⚠️ Sometimes | |
| 6 | E21 / F21 | Motor fault / low rotation speed | ⚠️ Sometimes | |
| 7 | F43 / E43 | Drum not turning / motor jam | ⚠️ Sometimes | |
| 8 | E32 | Unbalanced load | ✅ Yes | |
| 9 | E90–E92 | PCB / software communication error | ❌ Usually no | |
| 10 | E20 / F20 | Unexpected heating during cycle | ⚠️ Partial |
Primary Error Codes — Most Common Faults
F18
The E18 or F18 is the single most common Bosch washer fault code I deal with. When it appears, the machine has detected that water isn't draining within the allowed time window. In the vast majority of cases — probably 80% — the culprit is a blocked drain pump filter stuffed with lint, coins, hair clips, or small garments that snuck past the drum seal.
Bosch front loaders have a drain pump filter behind a small service flap at the bottom front of the machine. I've seen filters so blocked that nothing could pass through at all. It takes about 5 minutes to clean, and it immediately resolves the E18 in most cases. The drain hose position is the second thing to check — if it's pushed too deep into the standpipe or has a kink, gravity alone can prevent proper drainage.
✓ How to Fix E18 / F18
- Pull the machine slightly away from the wall and check the drain hose at the back for any kinks, pinches, or blockages. The hose should not be inserted more than 15 cm into the standpipe.
- Open the small service flap at the bottom-front of the machine. Place a shallow tray or folded towel underneath — there will be residual water.
- Find the small black emergency drain tube next to the filter cap. Pull it out and let the trapped water drain into the tray first.
- Slowly turn the main filter cap counterclockwise and remove it. Pull out any debris — lint, coins, fabric scraps — and rinse the filter under running water.
- Reinstall the filter firmly (hand-tight), close the service flap, and run a short spin cycle to confirm drainage is working.
F16
The E16 or F16 code means the door interlock switch hasn't confirmed a locked state before the cycle can begin. Bosch's door interlock is an electronic safety device — the machine physically won't run until it receives a confirmed closed-and-locked signal. This protects against water leaking out during the spin cycle.
About half the E16 cases I see are caused by something simple — a small sock or piece of fabric trapped in the door seal creating a gap, or the door not being pushed closed firmly enough. The other half involve a worn latch tongue, a faulty door switch, or in rarer cases, a wiring fault back to the control board.
✓ How to Fix E16 / F16
- Open the door fully and inspect the rubber door gasket (seal) around the entire perimeter — run your fingers around it looking for any trapped clothing or debris creating a gap.
- Check the latch strike plate on the door frame and the latch tongue on the door itself for visible damage, wear, or misalignment.
- Press the door firmly shut — push it until you hear and feel a definite click. Sometimes the latch just needs a firm push.
- Unplug the machine for 2 minutes (this performs a soft reset), plug back in, and try starting a cycle.
- If the door appears closed but E16 persists, check whether the door hinge has any droop or play — an overloaded drum can torque the door out of alignment over time.
F17
The E17 or F17 code fires when the machine can't get enough water into the drum within a set time — typically 3 to 5 minutes. Bosch washers allow this window for the fill cycle, and if the required water level isn't reached, the cycle aborts and E17 is displayed.
In most cases it comes down to one of three things: a closed or partially closed water tap, a kinked inlet hose, or clogged mesh filter screens inside the inlet valve connections. These filters catch sediment from the water supply and, in hard water areas especially, they can get completely blocked after a few years without cleaning.
✓ How to Fix E17 / F17
- Check that the cold water tap (and hot water tap if connected) behind the machine is fully open — not just partially turned.
- Inspect the two fill hoses for kinks, pinches, or any damage. Straighten any bends and make sure the hoses aren't compressed against the wall.
- Turn off the water supply. Unscrew the fill hoses from the back of the machine. Inside the inlet valve ports you'll find small mesh filter screens — pull them out with needle-nose pliers and rinse under a tap to remove sediment buildup.
- Reconnect hoses, open the water supply fully, and restart a cycle.
F23
The E23 or F23 code means Bosch's AquaStop flood protection system has kicked in. There is a float switch in the base of the machine — when water collects in the drip tray at the bottom (indicating a leak somewhere inside), this float rises and triggers E23, shutting down the machine to prevent flooding.
This is one of the more serious codes because it means water has actually escaped from where it should be. It could be a loose hose connection, a cracked drum seal, a leaking pump, a split inlet hose, or a faulty detergent drawer seal — finding the actual source requires some investigation.
✓ First Steps for E23 / F23
- Stop the machine immediately and turn off the water supply at the tap.
- Pull the machine forward carefully and look underneath — can you see water on the floor or in the base tray?
- Check all accessible hose connections at the back — inlet hoses and drain hose — for any visible drips or loose connections.
- Inspect the detergent drawer and its housing for any soap buildup or cracking that could be causing dripping.
- Check around the door seal (gasket) for any tears, holes, or areas where the seal has pulled away from the drum opening.
- Once you've found and fixed the leak source, tilt the machine slightly to drain any water from the base tray — the float switch won't reset until the tray is empty.
Heating & Temperature Codes
F19
The E19 or F19 code means the machine started its heating phase but couldn't bring the water up to the selected temperature within the allowed time. This almost always points to the heating element beginning to fail — either a partial break in the element or significant limescale buildup on it that's drastically reducing its efficiency.
In hard water areas, a heating element can develop a thick coating of scale over 3–5 years that insulates it so heavily it can barely heat the water at all. In other cases, the element has simply developed a high-resistance break and is only running at partial output.
✓ How to Respond to E19 / F19
- Unplug the machine and try a power reset — plug back in and start a cool wash to see if the error was a one-time glitch.
- If you're in a hard water area and haven't descaled the machine in over a year, run a descaling cycle with a washing machine descaler — this can dramatically improve heater performance.
- If the error recurs on heated wash programs, the heating element needs testing and likely replacing.
F20
The E20 code is the opposite of E19 — it fires when the machine detects heat building up during a phase where heating isn't supposed to be happening. This typically indicates a stuck heating relay on the control board, or in some cases the NTC temperature sensor giving wrong readings that are confusing the control logic.
✓ How to Fix E20 / F20
- Turn the machine off immediately.
- Unplug for at least 5 minutes to allow a full control board reset.
- Plug back in and try running a cold wash only — if E20 appears even on a no-heat program, the fault is persistent and needs professional diagnosis.
Motor & Rotation Codes
F21
The E21 or F21 code means the drum stalled or ran at a significantly lower speed than commanded. The machine's tachometer (speed sensor) detected the discrepancy and threw the error. This can be caused by a mechanical obstruction, worn motor carbon brushes, or a failing motor altogether.
Carbon brushes are a consumable part in older Bosch motors — they gradually wear down over years of use and eventually lose contact with the motor's commutator. Replacing them is a moderately complex DIY repair involving removing the back panel and motor, but it's significantly cheaper than a full motor replacement.
✓ First Steps for E21 / F21
- Open the door and manually try to rotate the drum by hand — it should turn smoothly with light resistance. Any grinding, binding, or inability to turn indicates a mechanical obstruction or bearing issue.
- Check for clothing trapped between the drum and the door seal — this can jam the drum unexpectedly.
- If the drum turns freely by hand but E21 persists in operation, the carbon brushes or motor tachometer are the likely suspects.
E43
F43 indicates the motor can't rotate the drum at all — more severe than E21 which shows intermittent stalling. Causes include a completely seized motor, worn-out brushes at end-of-life, a broken motor-to-drum belt on belt-driven models, or wiring failure between the motor and control board.
✓ First Steps for F43
- Try rotating the drum manually — if it's completely seized and won't move at all, a mechanical blockage or bearing failure may be the cause.
- Unplug for 5 minutes and try again — occasionally a motor thermal cutout trips and needs time to reset.
- On belt-driven older models, if the drum rotates freely but the motor spins without driving the drum, the drive belt has snapped.
Bosch's E32 is their equivalent of an unbalance detection code. The machine tried to spin and detected that the load was too asymmetrically distributed to safely accelerate to full speed. It will attempt to rebalance a few times automatically by reversing and redistributing, but eventually gives up and shows E32.
This most commonly happens with single heavy items — duvets, large towels, jeans — that bunch together on one side of the drum. It also appears more frequently on machines that aren't perfectly level.
✓ How to Fix E32
- Open the door and manually redistribute the load — shake out bunched items and spread them around the drum evenly.
- If washing one very heavy item, add 2–3 lighter items to help even out the weight distribution.
- Check that the machine is perfectly level — place a spirit level on top and adjust the leveling feet if needed.
- Close the door and press Start to resume.
Sensor & Pressure Codes
F25
The turbidity sensor monitors water clarity to help the machine determine how much detergent and water is needed per cycle — it's part of Bosch's intelligent load sensing systems. When this sensor malfunctions, the machine can't make accurate cycle decisions and throws E25.
F26
The pressure sensor tells the machine how much water is in the drum. An E26 fault means this sensor is giving incorrect readings — the machine can't reliably control its water fill and drains as a safety measure. On some occasions, a blocked pressure sensor hose (the thin plastic tube connecting the sensor to the drum) causes false E26 readings.
✓ Basic E26 Check
- Unplug the machine for 5 minutes and try a power reset — occasionally resolves a temporary sensor glitch.
- On accessible models, check if the pressure sensor hose (thin tube from sensor to drum base) is clear and not blocked or kinked.
F27 is closely related to E26 — both involve the pressure sensing system. F27 specifically refers to a pressure-related issue often caused by insufficient water supply combined with a sensor that can't confirm the correct level. Check that the water supply is fully open and the inlet filters are clean, then perform a power reset. If F27 persists, professional service is required.
F28
The flow sensor measures how much water is entering the machine. An E28 fault means the sensor is either giving no reading or an out-of-range reading during a fill cycle. This cannot be resolved by the user — it requires a technician to test and replace the flow sensor or its associated wiring.
Advanced & Electrical Fault Codes
Unlike E23 which fires when the base float switch detects water in the drip tray, E36 specifically points to a fault within the AquaStop hose assembly itself or the solenoid valve that's part of it. Bosch's AquaStop hose has a built-in safety valve that shuts off the water supply if the outer hose jacket detects moisture — E36 means this system has detected a fault.
The E56 code indicates an unexpected communication error between the main control board and a secondary module — this could be the motor module, the user interface board, or another subsystem. A power reset sometimes clears this if it was caused by a voltage spike.
✓ How to Address E56
- Turn the machine off and unplug from the wall.
- Wait 5 minutes for the capacitors to discharge fully.
- Plug back in and try starting a cycle.
–E92
The E90 series of codes indicate internal control board errors — software communication faults, PCB overheating, or data corruption. These are among the least DIY-friendly codes on the list. A hard reset sometimes clears a temporary E90 caused by a power surge, but recurring E90 codes almost always mean the main PCB needs replacement or reprogramming.
✓ Basic Reset Attempt
- Unplug the machine for at least 10 minutes.
- Plug back in and attempt to run a cycle.
NTC
The NTC (Negative Temperature Coefficient) thermistor is the temperature probe that monitors water temperature throughout the wash cycle. An E37 code or NTC error indicates this probe has short-circuited — meaning it's returning a zero-resistance reading that tells the control board the water is impossibly hot, causing it to abort the program.
The E38 code indicates a voltage problem that caused the program to be interrupted. This can happen due to a brown-out (temporary voltage drop), a shared circuit with other high-draw appliances, a loose mains connection, or in some cases a faulty power supply within the machine itself.
✓ How to Address E38
- Check the condition of the power cord — look for any damage, kinks, or burn marks near the plug or where it enters the machine.
- Check the wall socket with another appliance to confirm it's delivering consistent power.
- Ideally plug the washer into a dedicated circuit or at minimum ensure it's not sharing with other high-draw appliances.
- Unplug for 2 minutes and restart.
Symbol & Status Indicators — Not Always Errors
✓ How to Deactivate Child Lock
- Make sure the machine is powered on.
- Press and hold the Start button (or the button marked with a key/lock symbol) for 3–5 seconds.
- The machine will beep and the key symbol will disappear, confirming the lock is deactivated.
A flashing tap symbol (faucet icon) on the Bosch display is their visual shorthand for a water supply problem — equivalent to E17 in many situations. The machine started a fill cycle but isn't detecting water entering the drum. Check that the tap is fully open, the hoses aren't kinked, and the inlet filters are clean. See the E17 section above for the full troubleshooting sequence.
Blink
If your Bosch washer doesn't have a digital display, it communicates faults through a pattern of LED flashes on the control panel. The number of flashes corresponds to an error number — for example, 1 flash = Error 1 (door issue), 2 flashes = Error 2 (water supply), 3 flashes = Error 3 (heating), 4 flashes = Error 4 (drain), 5 flashes = Error 5 (motor drive), etc.
Frequently Asked Questions
Bosch Washing Machine Error Codes — Common Questions
Still Getting the Error Code?
If your Bosch washing machine error persists after following the troubleshooting steps above, our certified repair team can diagnose and fix all Bosch washer models — Serie 2, 4, 6, and 8.
Get a Free Repair Quote →Official Bosch sources: Bosch Canada · Bosch UAE
© 2026 WasherFixers.com · All error code information independently verified by certified appliance technicians
Post a Comment