Bosch Dryer E:18 Flags the Sensor Above the Heater

What E:18 means

Bosch labels the sensor above the heater TH, and E:18 is its problem code. The manual lists two causes: a sensor with damaged or shorted wiring, and a circuit where the temperature never climbs once a program starts. That second one is why the manual sends you to the heating circuit and the bimetal switch as well. In other words, the dryer may be failing to produce heat, not just failing to measure it.

Common causes of E:18

Heater-side NTC sensor with damaged insulation or a short in its wire
Open heater circuit, which leaves the control seeing no rise in temperature
Sensor plug that is loose or corroded

✓ One safe check you can try

No check at home applies. Do one useful thing before we arrive: run a short cycle and note whether the drum ever warms up, even a little. Total absence of heat sends us toward the heating circuit and not only the sensor. After that, keep the cabinet shut and leave the breaker off.

! Why to stop there

A missing temperature rise is a listed cause, so E:18 may be a failed heating circuit instead of a sensor, and the two repairs differ greatly.
The sensor lives directly above the element, so reaching it means working on the hottest panel in the machine.
Bosch advises checking the sensor wire and plugs before blaming the sensor, since a wire with a short is indistinguishable from a dead sensor when viewed from outside.
Heater terminals are exposed and remain energized until the breaker is switched off.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

→Same appliance

Other Dryer codes

E:15Bosch Dryer E:15 Means the Heating Circuit Is Not Working E:17Bosch Dryer E:17 Reports the Exhaust Air Sensor Is Off E:03Bosch Dryer E:03 Appears When Laundry Will Not Get Dry Enough E:11Bosch Dryer E:11 Is a Quiet Early Warning About Airflow E24Bosch Dryer E24 Means the Self-Check Found an Electronics Error E10Bosch Dryer E10 Points to the Control Module or Its Wiring E12Bosch Dryer E12 Means It Overheated From Blocked Airflow E52Bosch Dryer E52 Signals a Problem With the NTC Temperature Sensor

E:18E:18 questions

How does E:18 differ from E:17?

They involve two separate sensors: E:17 belongs to the NTC down in the exhaust channel, and E:18 to the one mounted over the heater. Bosch gives each a code because each informs the control differently.

Does E:18 always call for a new sensor?

Not necessarily. No temperature rise is among the documented causes, which points at the heating circuit, so the sensor is only one thing we test.

What happens during your visit?

With the power isolated, we test the sensor, its wire and plug, and the heating circuit. We then state the price in writing, and nothing is repaired until you approve it.