Dishwasher shows E12, often associated with rinse aid or detergent dosing systems on professional models.

Safety first: Disconnect power and use appropriate PPE when handling commercial detergents and rinse aids.

• Check chemical levels: Verify that external detergent and rinse aid containers are not empty and that suction tubes are submerged.
• Inspect suction and dosing tubes: Look for kinks, air leaks, or crystallized chemical blocking the lines. Flush or replace tubing as needed.
• Prime dosing pumps: Many professional dishwashers allow manual priming. Follow the user manual to prime the detergent and rinse aid pumps until liquid flows without air bubbles.
• Test dosing pump: If the pump does not run during priming, check its wiring and replace the detergent dosing pump or rinse aid dosing pump if faulty.