Bosch Washer Error Codes: Complete 2026 Troubleshooting Guide

How Bosch Error Codes Appear on Your Washing Machine

Bosch washing machines have used the same E/F error code system across nearly two decades of models, but how those codes are displayed depends on your series:

• WAT, WAW, WAS Series (2015–present): Error codes appear on the LED or LCD display as E:18, F:17, etc. The colon is Bosch's formatting convention — other guides may show the same code without the colon. E and F codes with the same number are interchangeable; E:18 and F:18 describe the same fault.
• WFMC Series (2004–2012, US market): These older front-loaders use a combination of LED blink sequences and display readouts depending on the sub-model. To retrieve stored fault codes, press and hold the Menu and Select buttons simultaneously, then rotate the cycle selector counterclockwise to the Permanent Press Cold position. Hold until P1:Errors appears. Press the Start/Pause button to display the most recent fault code. The WFMC series stores up to 8 cycle histories.
• Older pre-2004 models: Fault display varies by exact model. Consult the model-specific service manual; codes may appear as a series of LED blinks rather than alphanumeric characters.

On all current WAT/WAW series, pressing Start/Pause and holding for 3 seconds cancels the active program and clears the error display. The code returns if the fault is not resolved.

Complete Bosch Washer Error Code Reference

Drain Error: E18 — Step-by-Step Fix

E18 is the number-one most common fault code on Bosch washing machines. It fires when the drain pump cannot empty the drum within the program's drain cycle time — almost always because the pump filter is clogged with lint, coins, hair ties, or other debris that accumulates over months of use. Bosch recommends cleaning the filter every 3 months; industry data shows a large majority of service calls for E18 are resolved by filter cleaning alone.

Before you begin: The pump filter on all Bosch front-loaders is behind the service panel at the front bottom of the machine (the small door or removable kick plate). There will be standing water in the drum that needs to drain through the small drain hose adjacent to the filter before you unscrew it.

1. Open the front service panel. You will see two items: a small rubber cap on a short hose (the emergency drain hose) and the round filter cap.
2. Place a shallow container (a baking sheet or storage tray works well) directly under the filter area. Pull out the emergency drain hose, remove the rubber cap, and let the residual water drain fully into your container. This step prevents a flood when you unscrew the main filter.
3. Once drainage slows to a drip, turn the main filter cap counterclockwise and pull it straight out. Clean any debris from the filter body under warm running water. Inspect the pump cavity (the recess the filter sits in) for coins, buttons, or small objects stuck in the impeller — remove anything you find.
4. Manually spin the pump impeller (the plastic fan visible at the back of the cavity) with a finger or pen. It should rotate freely. If it is jammed, carefully remove the obstruction.
5. Reinstall the filter cap, replace the emergency drain hose cap, and close the service panel. Run a short spin cycle and confirm the drum empties cleanly.

If E18 returns after filter cleaning: The drain hose itself may be kinked or partially blocked. Trace the corrugated drain hose from the rear of the machine to where it connects to the sink drain or standpipe. A kink at the back of the machine (often caused by the machine being pushed too close to the wall) is a common culprit. The hose should also loop upward to at least 60 cm (24 inches) off the floor before descending to the drain connection — an improperly routed hose allows water to siphon back and can trigger E18 intermittently. If the hose and pump are both clear and E18 persists, the pump motor itself may have failed, which requires part replacement.

Fill Errors: E17 and E23

E17 — Insufficient Water Supply

E17 fires when the machine starts a fill cycle but the water level sensor does not detect the expected rise in drum water level within the time limit. The root cause is almost always upstream of the machine itself.

Diagnostic sequence (in order of likelihood):

• Supply valves not fully open: The hot and cold water shutoff valves behind the machine must be fully open — even a quarter-turn closed reduces flow enough to trigger E17. Turn each valve counterclockwise as far as it goes.
• Inlet hose screens clogged: Where the fill hoses connect to the back of the machine, there are small mesh screens inside the inlet ports. These catch mineral sediment and can restrict flow significantly after a few years. To clean: shut off the water, disconnect the hoses, and use needle-nose pliers or a toothpick to remove and rinse the screens. Reinstall carefully — the screens must seat flat to prevent sediment from reaching the inlet valve.
• Kinked inlet hose: A hose kinked behind the machine after a service visit or move will restrict fill. Pull the machine forward slightly and inspect both hoses across their length.
• Failed water inlet solenoid valve: If supply pressure and screens are confirmed good and E17 persists, the dual-port solenoid valve inside the machine that controls fill flow may have failed (either stuck closed, or one port failed). Solenoid valve replacement is a common Bosch washer repair in the $120–$200 range for parts and labor.

E23 — Pressure Sensor (Water Level) Fault

E23 indicates the pressure sensor that measures drum water level is not reading correctly. The sensor is connected to the bottom of the drum via a small plastic tube; if this tube becomes kinked, blocked with mold/residue, or disconnects, the sensor cannot read drum level and fires E23.

DIY first step: Locate the pressure sensor tube — it runs from a port near the bottom front of the outer drum up to the pressure sensor mounted on the rear cabinet wall. Disconnect the tube at both ends and blow through it (like a straw) to confirm it is clear. Reconnect firmly. If the tube is cracked or the sensor reads incorrectly with a clear tube, the sensor requires replacement.

Door Lock Error: E16

Bosch washers use an electronic door interlock (a bi-metal or wax-motor actuator) that must engage within a few seconds of pressing Start. E16 fires when the control module does not receive a confirmation signal that the door is locked.

Why E16 fires — ordered by frequency:

• Door physically obstructed: A sock, sleeve, or laundry tag caught between the door gasket and drum rim prevents the door from seating fully. Open the door, check the entire perimeter of the gasket, and retry.
• Door gasket (bellow) folded inward: The rubber door seal on front-loaders can fold back on itself after heavy use. Manually press the gasket back into position around the drum opening and confirm the door closes flush before pressing Start.
• Door latch strike worn or misaligned: The plastic hook on the door catches on the metal strike inside the machine body. If the hook is worn or the door has sagged slightly (common on older hinges), the interlock cannot engage. Examine the door catch and strike for wear; door hinge replacement restores alignment.
• Failed door interlock actuator: If the door closes and latches properly but E16 still appears, the interlock's internal bi-metal or wax motor has failed. This is a part replacement — the interlock sits inside the machine just behind the door opening and is accessible after removing the front panel. Replacement interlocks for most WAT/WAW series cost $35–$70 in parts.

Motor and Spin Code: E21

E21 (also displayed as F21) signals that the drum motor is not reaching the rotation speed commanded by the control module during a spin cycle. The diagnosis and fix depend critically on the age of your machine.

Pre-2015 Models — Carbon Brush Wear

Bosch front-loaders built before approximately 2015 use a brushed universal motor. The carbon brushes that press against the motor commutator are consumable parts designed to wear out — typically after 5–8 years of regular use. Worn brushes are the most common cause of E21 on older machines and produce several characteristic symptoms:

• Drum spins during the wash phase but cannot reach spin speed (800–1400 RPM) during the spin cycle
• Motor makes a scraping or intermittent buzzing sound during acceleration
• Code appears inconsistently — works for a few cycles, then fails again as brushes deteriorate further

Carbon brush replacement is a moderately advanced DIY repair. The brushes are accessible from the rear of the machine after removing the back panel. They slot into holders on each side of the motor and are secured with a retaining clip. New brushes for most Bosch motors cost $15–$30 for a pair and restore full spin performance when the motor commutator itself is not damaged. If the commutator is grooved or burned, the motor requires professional service or replacement.

Post-2015 WAT/WAW Models — Brushless Motor

Bosch's current 300/500/800 Series washers use a brushless inverter-driven motor — there are no carbon brushes to replace. E21 on these machines indicates a fault in the motor control module (inverter board), the motor winding itself, or the tachometer that reports drum speed to the control module. All of these repairs require a service technician with diagnostic equipment.

Heating Codes: E02 and E13

E02 — Heating Element or Heater Circuit Fault

E02 means the control module commanded the heating element to activate but did not detect the expected temperature rise within the programmed time. The heating element in a Bosch washer sits at the bottom of the outer drum and is responsible for heating wash water to the selected temperature (30°C, 40°C, 60°C, or 90°C programs).

Testing the element: Disconnect power to the machine, access the element from the rear by removing the back panel, and disconnect the element's two spade connectors. Set a multimeter to resistance (Ω) mode and probe both terminals. A healthy Bosch heating element reads approximately 20–30 Ω. An open circuit (infinite resistance / OL) indicates a burned-out element requiring replacement. Element replacement on a Bosch front-loader typically costs $80–$140 in parts plus labor.

Also test the NTC temperature sensor (see E13 below) — a faulty sensor can falsely report that the element is not heating even when it is working correctly.

E13 — NTC Temperature Sensor Fault

The NTC (negative temperature coefficient) thermistor measures drum water temperature and feeds readings to the control module. E13 fires when the sensor's resistance reading falls outside the expected range — either too high (open circuit / sensor disconnected) or too low (shorted).

At room temperature (~25°C), a healthy Bosch NTC sensor reads approximately 10,000 Ω (10 kΩ). At 60°C wash temperature, resistance drops to roughly 2,500–3,000 Ω. Values far outside these ranges confirm a failed sensor. NTC sensors are inexpensive ($15–$30) and relatively accessible once the rear panel is removed.

Note: E13 on older models and some regional variants can indicate incoming water temperature is too high rather than a sensor fault — if your machine fills from a hot-water line with a very high boiler temperature, the sensor reads correctly but trips the code. Confirm your supply connection.

How to Reset Any Bosch Washer Error Code

The standard reset procedure applies across all current WAT/WAW Bosch washers:

1. Press and hold Start/Pause for approximately 3 seconds. The machine cancels the active program and the display returns to the home screen.
2. Turn the program selector to the Off (0) position, wait 10 seconds, then turn it back to a program. This is the equivalent of a soft power cycle.
3. For board-level faults (E01, E02, E32, E43) that do not clear with the above: unplug the machine from the wall for a full 30 seconds to allow capacitors to discharge completely. Restore power and retry.

Resetting only clears the error display — it does not fix the underlying fault. A code will return when the next cycle reaches the same failure point. If a code clears and does not return for several cycles, the fault may have been transient (e.g., a momentary water pressure drop triggering E17). If it returns consistently at the same point in the cycle, diagnose and repair the cause before using the machine further.

Repair vs. Replace Math for Bosch Washers

Bosch's above-average build quality changes the repair-or-replace calculation. Because these machines routinely reach 12+ years, it is economical to repair them at ages that would make a budget front-loader a replacement candidate.

A comparable Bosch replacement washer (300 Series) retails for $900–$1,100; 500 and 800 Series are $1,100–$1,400. Applying the 50% rule sets the replacement threshold at $450–$700. Most repairs in the table above fall well below that threshold for machines under 10 years old.

Know your machine's true age before committing. The model year printed on a sticker or in marketing materials is not the same as the manufacturing date — a 2023 model-year machine might have been manufactured in late 2021 and sat in a warehouse. Your actual manufacturing date comes from the serial number. Use our Bosch serial number decoder to get the exact production date, then apply the repair-vs-replace math above against the actual age, not the model year.

Also check for open recalls before spending money on a repair. If your model is under an active CPSC recall (Bosch has had several washing machine-related safety notices over the years for door latch issues), the manufacturer may cover parts or labor at no cost. Run your model number through a recall check before scheduling a service call.