What E:18 Means
E:18 is the heater-side temperature sensor fault, which Bosch abbreviates TH and locates above the heater itself. The causes listed are a sensor that is damaged or shorted in its wiring, and a circuit that shows no temperature rise at all after a programme starts, which is why the manual pairs the sensor check with a check of the heating circuit and its bimetal switch.
Common Causes of E:18
- Heater NTC sensor damaged or short circuited in its wiring
- Break in the heater circuit so no temperature rise is detected
- Loose or corroded sensor connector
🔧 One Safe Check You Can Try
No home check applies here. What is worth recording before the visit is whether the drum ever gets warm at all, because a complete absence of heat points the diagnosis at the heating circuit as well as the sensor.
⚠ Why You Shouldn't Go Further Than That
- Because no temperature rise is one of the documented causes, this code can indicate a heating circuit failure rather than a sensor failure, and those are very different repairs.
- The sensor sits directly above the heater, so accessing it means working in the hottest part of the machine on the panel closest to the element.
- Bosch specifies checking the sensor wire and its connectors before condemning the sensor, and a short in the wire looks identical to a dead sensor from outside.
- The heater assembly is live until the machine is isolated at the breaker, and the terminals are not shrouded.
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.