What E:11 Means
Bosch fits two temperature sensors, called NTCs, to the heat pump so that each can check the other. E:11 is logged when their readings no longer agree or fall outside the expected resistance band, at which point the control stops trusting the water temperature it is being told. Bosch's instruction is to measure both sensors and replace the heat pump if either fails, or repair the harness if the connections are at fault.
Common Causes of E:11
- One of the two heat pump NTC sensors has drifted or failed
- Loose or corroded connector at the heat pump
- Damaged wiring between the heat pump and the power module
🔧 One Safe Check You Can Try
There is no meaningful home test for this one, because the check is a resistance reading taken at specific pins on the pump connector with the machine dead. What you can note is whether wash water has felt cooler than usual, which supports the diagnosis.
⚠ Why You Shouldn't Go Further Than That
- The NTCs are built into the heat pump on this platform, so a failed sensor means a pump assembly, and confirming that before ordering matters.
- Bosch names the exact terminal pairs to measure across, and probing the wrong pins on a six-pin connector risks damaging the pins themselves.
- The heat pump is in the base of the machine beneath the tub, surrounded by the water circuit it drives.
- Twin-sensor faults are often a connector problem rather than a sensor problem, and that distinction is worth a technician's meter before anyone buys a part.
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.