What 2 Means
A value of 2 in the service test programme of an older Bosch dishwasher is the heating system fault. Bosch's own definition is deliberately broad, naming five components in one line: the heater, the high-limit thermostat, the flow switch, the NTC temperature sensor and the heater relay on the control module. It is the same group of parts behind the long-cycle display on these machines.
Common Causes of 2
- Flow-through heater failed or the high-limit thermostat open
- Flow switch or NTC temperature sensor faulty
- Heater relay on the control module failed
🔧 One Safe Check You Can Try
Run the kitchen hot tap until it runs hot before starting a cycle, because these machines heat the incoming water rather than waiting for it and a cold fill makes a healthy heating system look slow.
⚠ Why You Shouldn't Go Further Than That
- Five different components share this one number, and replacing them in turn is how a modest repair becomes an expensive guessing game.
- The high-limit thermostat is a safety cut-out, and bridging it to get heating back removes the protection it exists to provide.
- The heating circuit runs live in a wet tub, so any continuity check starts at the breaker.
- On machines of this age the heater terminals corrode, and a terminal that crumbles during removal turns a part swap into a harness repair.
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.