Bosch E27: Supply Voltage Below Minimum
Medium severity
E27 means Bosch's control board measured supply voltage below the level it needs to run safely, so it shut the cycle down rather than operate underpowered.
A cycle that was running normally suddenly stops, or the dishwasher won't start at all and E27 sits on the display the moment you press the button. It can happen once, during a storm or a heavy-appliance moment elsewhere in the house, or it can come back on nearly every cycle.
Applies to: Bosch 300, 500, 800 series dishwashers with electronic displays (most models sold in the US since roughly 2008).
What it means
The control board has detected supply voltage below its minimum operating threshold (commonly cited around 170-220V depending on model), so it shuts the machine down to protect the heater and motor from running underpowered.
Put simply, this is a protective shutoff rather than a failure of the dishwasher itself — Bosch would rather stop the cycle than run a heater and motor on brownout-level power that could stress or damage them over time.
Common causes
The voltage problem can be real, originating in the house wiring, or it can be the control board misreading power that's actually fine:
- A genuine household voltage sag or brownout on the circuit feeding the dishwasher
- A loose or corroded wiring connection between the outlet/junction box and the dishwasher
- Corrosion on small solder points or connectors on the control board itself, which can falsely trigger a low-voltage reading even when house power is fine
What you can check yourself
These checks help tell house wiring apart from a control-board issue before anyone opens a panel:
- Reset power to the dishwasher at the breaker for about 30 seconds and try a cycle again
- Check that the dishwasher isn't sharing an overloaded circuit with other high-draw appliances
- Note whether the error happens at a specific time of day (which can point to a neighborhood voltage dip) versus every single cycle
Call a professional when
Because this code points to either house wiring or the control board, have an electrician check incoming voltage at the outlet if it's a whole-house issue, or an appliance technician check the control board if voltage at the outlet tests normal.
Related
- Bosch dishwasher codes hub
- Bosch E01 — control fault, meaning varies by model
- Bosch E09 — heating element open circuit
- Dishwasher Won't Start