Machine does not start brewing, display shows E01 shortly after pressing start.

Safety first: Unplug the coffee maker before inspecting parts. Never work on the unit while it is connected to mains power.

Step-by-step:

• Check tank seating: Remove the water tank completely and reinsert it firmly. Make sure it clicks into place and sits flush with the body of the Tefal coffee maker.
• Clean the tank and float: Remove the tank, empty it, and rinse thoroughly. If your tank has a magnetic float, check that it moves freely. Clean any limescale or coffee residue with warm water and a little white vinegar, then rinse well.
• Inspect the tank magnet/float: If the float is stuck at the bottom or top, gently move it with a non-metallic tool until it slides freely. If the magnet capsule is cracked or filled with water, the tank assembly may need replacement.
• Clean the tank sensor area: On many Tefal models, a reed switch or optical sensor sits behind the tank area. Wipe the contact area with a soft cloth to remove moisture or scale that may interfere with detection.
• Test the microswitch (if accessible): With the unit unplugged, remove the rear or side cover (if you are comfortable and this does not void warranty). Locate the tank presence microswitch behind the tank slot. Press it manually and listen for a clear click. If it does not click or feels loose, it may be defective and require replacement.
• Reassemble and test: Refit the tank, plug the machine back in, and try a brew cycle. If E01 persists after cleaning and reseating, the tank sensor or control board may be faulty and professional service is recommended.