Dishwasher displays E19, often related to the water softener or regeneration system.

Safety first: Disconnect power before accessing side panels.

• Access softener valve: On many Bosch models, the softener and its valve are integrated into the side heat exchanger assembly.
• Inspect wiring and connectors: Check the small regeneration valve coil and its connector for corrosion or loose fit. Reseat the connector.
• Test valve coil: Measure resistance of the regeneration valve coil. An open or shorted coil indicates a bad valve.
• Check for blockages: Inspect the softener channels and salt reservoir area for heavy salt bridging or debris. Break up salt bridges and refill with proper dishwasher salt.
• Replace valve or heat exchanger: If the valve is defective and not sold separately, the entire heat exchanger/softener assembly may need replacement.