Thermador Oven E118 — Temperature Sensor Failure

What does Thermador E118 mean?

The oven temperature probe (NTC sensor) is reading outside the valid range. The control unit cannot confirm a valid cavity temperature and will not allow cooking modes to operate.

What causes Thermador E118?

• Failed NTC temperature sensor
• Burned wiring harness to the sensor (common after extended self-clean cycles)
• Control board sensor input circuit failure

How a technician tells the causes apart

• With the breaker off, open the oven and examine the probe housing at the top-rear of the cavity: a cracked ceramic insulator or a visibly charred tip usually means the sensor itself is the problem before you measure anything.
• Trace the wiring from the probe back toward the rear of the cabinet, breaker still off, feeling for brittle or discolored insulation. Repeated long self-clean cycles cook this harness over the years even when the sensor is fine.
• Check the connector where the harness plugs into the control board for scorched pins or a latch that won't click fully home, power still disconnected — a burned connector can mimic a failed sensor from the board's point of view.
• Measure the probe's resistance at its two terminals with the breaker still off, and compare the reading to a known-good probe at room temperature if you have one on hand: a reading of zero or infinite (OL) confirms the sensor has failed rather than just drifted.
• Test continuity along the full harness, from the probe's connector to the board's connector, power still cut. A wire that goes open partway through the run points to damaged wiring, not the sensor or the board.
• If the probe and harness both test good, a technician can check the sensor input circuit directly at the control board with the oven powered — verifying that means working on an energized board, and that step belongs to a qualified technician only.

A cracked or open probe is the cheap fix — the NTC sensor is a small, inexpensive part on its own. A burned harness means replacing that section of wiring too, since a new probe plugged into cooked insulation will just fail again. If neither one checks out bad, the fault is on the control board itself. Match any of these to your exact range using the rating plate, which sits on the door frame or the side panel next to the oven cavity — open the door fully to see it.

How to fix Thermador E118 yourself

1. 1 Power cycle the oven at the breaker: off, wait a minute, back on. If E118 returns, switch the breaker off again and leave it off for everything below.
2. 2 With the breaker off, inspect the sensor probe at the top-rear of the oven cavity — look for visible wire damage near the ceramic insulator.
3. 3 Still with the breaker off, measure the sensor across its terminals with a multimeter in resistance mode — on Thermador models the NTC should read approximately 1000 ohms at 25°C (77°F), and an OL reading indicates failure. Never measure resistance on a live circuit.