Dishwasher shows E12; often linked to excessive foaming or unusual water level behavior.

Safety first: Turn off and unplug the dishwasher.

Step-by-step checks:

• Check detergent use: Confirm that only dishwasher tablets or powder are used. Hand dishwashing liquid will cause excessive foam and trigger errors.
• Rinse aid setting: Reduce the rinse aid dosage setting on the dispenser if you see persistent foam.
• Clear foam: Remove excess foam by adding 1–2 tablespoons of cooking oil to the sump and running a short rinse cycle. Repeat if necessary.
• Inspect dispenser: Check the rinse aid dispenser for leaks or cracks that could cause overdosing. Replace the dispenser if damaged.
• Sensors: If E12 persists with correct detergent use, inspect the level/foam sensor (if fitted) and its wiring. Replace if faulty.

After correcting detergent and dispenser issues, run several normal cycles to flush out residues.