What E123 Means
E123 is the under-range version of the probe fault: the probe is reading colder than the control will accept and the oven stops heating until it is removed. Bosch's first suggested check is whether the probe was pushed into frozen food, which reads below the allowable limit quite legitimately. Beyond that the manual points at the probe's own resistance, loose connections and pinched wiring.
Common Causes of E123
- Probe inserted into frozen or part-frozen food
- Probe element failed and reading low
- Loose connection or pinched wiring in the probe circuit
🔧 One Safe Check You Can Try
Remove the probe and let it come to room temperature, then try again with fully thawed food. Bosch names frozen food as the first thing to rule out, and it is the one cause you can eliminate without tools.
⚠ Why You Shouldn't Go Further Than That
- The most common cause is a use pattern rather than a fault, and dismantling an oven for it wastes both time and money.
- Probe resistance has to be compared with Bosch's published figure, which is not something guessed from a room-temperature reading.
- Pinched wiring in the probe circuit sits behind the cavity wall and is reached by drawing the appliance out.
- An oven that has stopped heating gives no way to confirm a repair by use until the work is already finished.
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.