Bosch Refrigerator Error Code E15

The E15 error code on a Bosch refrigerator indicates that the ambient temperature sensor is returning a reading outside its valid operating range, specifically at or above 60°C or at or below -55°C. Because these temperatures are physically impossible under normal kitchen or installation conditions, the control board interprets these extreme readings as a sensor fault rather than an actual temperature event. The ambient temperature sensor monitors the air surrounding the refrigerator and feeds that data to the control board, which uses it to adjust compressor cycling and fan operation for optimal efficiency.

The three root causes the system flags are a sensor break (an open circuit in the sensor or its wiring), a short-circuit (wiring conductors contacting each other or a grounded surface), or a loss of contact (a loose or corroded connector between the sensor harness and the control board). A broken sensor or open wire causes resistance to spike toward infinity, which the board reads as an extreme low temperature. A short-circuit drives resistance toward zero, producing an extreme high-temperature reading. Either condition pushes the reported value past the defined threshold and triggers E15.

Diagnosis begins with a physical inspection of the ambient sensor, its wiring harness, and all connector terminals. Technicians should check for visible wire damage, corrosion at the connector pins, and whether the connector is fully seated. If wiring appears intact, resistance testing of the sensor itself will confirm whether it has failed internally. A functioning NTC-type ambient sensor will show a measurable and temperature-appropriate resistance value; an open or shorted sensor will read near infinity or near zero ohms respectively.