Dishwasher shows E16; often associated with problems in the water softener or regeneration system.

Safety first: Disconnect power and water before accessing internal plumbing.

Step-by-step checks:

• Check salt level: Ensure the salt reservoir is filled with dishwasher salt and the cap is properly closed. Running without salt can damage the softener.
• Inspect regeneration valve: Locate the softener/regeneration valve (often near the side water chamber). Check for signs of leakage or burnt coil.
• Test valve coil: Measure resistance across the valve terminals. An open circuit indicates a failed coil that must be replaced.
• Clean brine area: Remove any salt crust or debris around the salt cap and neck. Blockages can affect regeneration flow.
• Wiring and sensor: Inspect the harness to the softener valve and any associated sensors. Repair or replace damaged wiring.

After repair, run a cycle and monitor for correct water hardness and absence of E16.