What 16 Means
A value of 16 in the service test programme of an older Bosch dishwasher is the water switch fault. The water switch is the diverter that decides which spray arm gets the pump output. On the full-text displays of the same generation Bosch splits this into two forms, no pulses detected from the switch and a switch that will not stop running, which are useful descriptions of how it fails.
Common Causes of 16
- Water switch motor failed or its position sensing lost
- Diverter jammed by debris
- Wiring between the switch and the control module faulty
🔧 One Safe Check You Can Try
Watch how the machine washes. One rack coming out consistently less clean than the other, across different loads, is the symptom of a diverter that is no longer stepping between positions properly.
⚠ Why You Shouldn't Go Further Than That
- The diverter sits in the pump housing under the tub, so reaching it means working beneath a machine fixed to the cabinetry.
- Because the test-programme numbers add together, a 16 can be accompanied by other faults that the single figure hides.
- The diverter motor is a live-voltage component, and the machine has to be fully isolated before the housing is opened.
- A diverter refitted out of position runs continuously, which is the second of the two failure forms Bosch describes.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.