Reversing a Failed Start on Bosch WAT28400

A washer that will not start can be frustrating, especially when it appears to do nothing after you press the power button. For the Bosch WAT28400, a “failed start” typically shows up as an error code on the display or simply a blank screen that never lights up. This guide walks you through diagnosing the problem, reversing a failed start, and restoring your machine to full working order.

Understanding the Symptoms

When a Bosch WAT28400 refuses to start, you may notice one or more of the following:

• Blank or flickering display – the digital panel may remain dark or blink intermittently.
• Error code “01” or “02” – a short‑coded message indicating a mechanical or electrical fault.
• Unresponsive start button – pressing the button does not trigger any audible click or change in indicator lights.
• No water fill or motor spin – the machine does not draw water or rotate the drum even after you select a cycle.

These symptoms usually point to either an internal software glitch or a hardware failure such as a faulty motor controller, relay, or sensor. The most common cause is a temporary software error that can be resolved with a reset or by clearing the error state. However, if the problem persists, a deeper inspection of the motor or control board may be required.

Safety First

Before you start any repair or reset procedure, it is crucial to take the following safety precautions:

1. Disconnect the Power – Unplug the washer from the mains outlet. The Bosch WAT28400 is designed to operate with a standard 240 V supply, and touching any internal components while powered can cause serious injury.
2. Drain the Water – If water remains in the tub, use a hose or a wet/dry vacuum to drain it. Excessive water inside the control panel can damage electronic components.
3. Ground Yourself – Wear an anti‑static wrist strap or regularly touch a grounded metal object to prevent static discharge from damaging the control board.
4. Read the Manual – Refer to the user manual for any specific instructions about electrical safety or troubleshooting for your model.

These steps protect both you and the machine during the troubleshooting process.

Step‑by‑Step Guide to Reverse a Failed Start

Below is a structured, step‑by‑step approach to diagnose and reverse a failed start on the Bosch WAT28400. Each step builds on the previous one, ensuring a thorough investigation of the most likely issues.

1. Verify the Power Supply

• Check the Outlet – Use a voltage tester to confirm that the outlet is delivering 240 V. A dead outlet or tripped breaker will keep the machine from powering on.
• Inspect the Cable – Look for visible damage, fraying, or kinks in the power cord. Replace any compromised cable.
• Test with Another Appliance – Plug a known‑working device into the same outlet to ensure it is functional.

If the outlet or cable fails this check, replace the faulty component before proceeding.

2. Examine the Door/Lid Switch

• Locate the Door Sensor – The WAT28400 has a door lock sensor that must detect a closed door to start.
• Manual Closure – Close the door firmly and press the start button. If the machine still refuses to start, the door switch may be stuck or defective.
• Use a Multimeter – Test the door switch for continuity. If it reads open, replace the sensor.

A faulty door switch is a frequent culprit in failed starts.

3. Check the Control Board and Reset Switch

• Open the Front Panel – Remove the front access panel by unscrewing the screws that secure it to the cabinet.
• Locate the Reset Switch – On most Bosch models, a small reset button is near the control board. It may be labeled “RST” or simply “Reset.”
• Press the Reset – Hold the reset button for about five seconds. The display may flicker or show a brief diagnostic mode.

If the reset clears the error code and the machine starts normally, the issue was a temporary software glitch. If not, proceed to the next step.

4. Inspect the Motor and Its Relays

• Identify the Motor Relay – The WAT28400 uses a relay to drive the motor. A burnt or stuck relay can prevent the machine from starting.
• Visual Inspection – Look for scorch marks, melted plastic, or a burnt smell around the relay and motor.
• Test the Relay – Use a multimeter to check for continuity across the relay terminals. If the relay does not cycle, replace it.

Motor failures may require a technician’s expertise, especially if the motor itself is damaged.

5. Examine the Water Inlet Valves

• Check Valve Operation – A failed start can occur if the machine thinks the water supply is blocked. Open the valve manually to confirm it moves freely.
• Test with a Multimeter – Measure resistance across the valve’s contacts. A reading of infinite ohms indicates a broken valve.

If the water inlet valve is defective, replace it before attempting to start the washer again.

6. Reset the Control Unit via the Main Power

• Unplug the Washer – Disconnect the power cord from the outlet.
• Wait – Leave the washer unplugged for at least 60 seconds. This allows any residual charge to dissipate.
• Reconnect – Plug the machine back in and press the start button. The control board should power up normally.

This “hard reset” often resolves software anomalies that a simple reset button cannot fix.

7. Verify the Display and Light Indicators

• Power‑On Test – When you plug the washer back in, the LED display should show the home screen or the selected cycle. If it remains blank, the display board might be faulty.
• Check for Error Codes – Any displayed code can be looked up in the Bosch service manual. For example, code “05” usually relates to a motor stall.
• Replace the Display Board – If diagnostics confirm a display issue, you will need to order a replacement part from an authorized Bosch distributor.

8. Confirm No Mechanical Obstructions

• Open the Drum – If the drum is stuck due to a mechanical obstruction, the motor will fail to start.
• Inspect for Foreign Objects – Look for lint, coins, or small items that might be wedged inside the drum or the agitator.
• Clear the Obstruction – Carefully remove any objects. If the drum does not rotate freely, consult a professional for further inspection.

If the Washer Still Won’t Start

After completing all of the above steps, a stubborn failure may indicate a deeper issue:

• Control Board Failure – A defective main board will prevent any operation. Replacement is required.
• Thermal Fuse – Some models include a thermal fuse that blows when the motor overheats. A blown fuse will need replacement.
• Electrical Wiring Fault – Loose or corroded connections in the wiring harness can prevent power from reaching critical components.

At this stage, it is advisable to contact Bosch customer support or a qualified appliance repair technician. They can run advanced diagnostics and replace any damaged parts.

Preventive Measures to Avoid Future Failed Starts

Preventive care can dramatically reduce the likelihood of a failed start. Consider the following routine maintenance tips:

• Regularly Inspect the Door Seal – Keep the rubber gasket clean and free of debris to ensure a proper door lock engagement.
• Keep Water Inlet Filters Clean – Debris in the inlet hoses can block flow and trigger water‑level errors.
• Avoid Overloading – Exceeding the manufacturer’s load limit stresses the motor and can lead to failure.
• Schedule Annual Professional Servicing – An annual checkup can spot wear on internal components before they become critical.
• Use Only Approved Detergents – Cheap or inappropriate detergents can leave residue that clogs sensors and valves.

By following these guidelines, you can maintain the health of your Bosch WAT28400 and keep it running reliably for years.

Frequently Asked Questions

What does the error code “01” mean?

Error code “01” on a Bosch washer typically indicates a motor stall or overload. It is often accompanied by a red LED flashing.

Can I DIY a motor replacement?

Motor replacement involves handling high‑voltage components and requires a good understanding of electrical systems. If you are not comfortable, it is safer to seek professional help.

How long does a reset take?

A soft reset using the reset button generally takes a few seconds. A hard reset via unplugging can take 1–2 minutes, including the waiting period for residual charge to dissipate.

Is it safe to start the washer without a door lock?

No. Modern washers will not start if the door lock sensor is not engaged. This safety feature prevents water leaks and potential hazards.

When should I replace the control board?

If repeated resets fail to clear error codes and you observe no display response, it is likely that the control board has failed and needs replacement.

Final Thoughts

A failed start on the Bosch WAT28400 can be traced back to a variety of causes ranging from simple power issues to complex control board failures. By systematically checking the power supply, door sensor, motor, water valves, and control board, most problems can be resolved quickly without the need for costly repairs. Always keep safety at the forefront: unplug the appliance, inspect the components carefully, and never hesitate to seek professional assistance when required.

Regular maintenance and mindful usage will further safeguard against future failures, ensuring that your washing machine continues to deliver efficient, reliable performance for years to come.