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Error code reference

Bosch Refrigerator Error Code r3

Refrigerator defrosting return abnormal or defective (RD-S)

Bosch codesBosch refrigerator codes

Refrigerator defrosting return abnormal or defective (RD-S) — defrosting return done by time limit of 50 minutes.

First step from the service manual

Measure the resistance between both terminals of the Fridge defrost heater (assembled with evaporator).

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What r3 means on a Bosch refrigerator

The r3 error code on a Bosch refrigerator indicates an abnormal or incomplete defrost cycle in the refrigerator compartment. Specifically, the defrost sequence failed to terminate normally through the defrost termination sensor (RD-S) and instead timed out after reaching the 50-minute safety limit. Under normal operation, the defrost heater warms the evaporator coil until the termination sensor detects a temperature threshold and signals the control board to end the cycle. When the sensor or heater fails to complete this handoff properly, the system defaults to the time limit as a fallback cutoff.

The primary components involved are the fridge defrost heater, which is physically assembled with the evaporator coil, and the defrost termination sensor (RD-S). A failed defrost heater, one that has gone open-circuit or developed high resistance, will prevent adequate heat generation, meaning the evaporator never reaches the target termination temperature within the allotted 50 minutes. The RD-S sensor itself can also fail, either reading falsely high temperatures that cut the cycle short or becoming unable to signal termination at all, which forces the time-limit shutoff.

The first and most critical diagnostic step is measuring the resistance across both terminals of the fridge defrost heater assembled with the evaporator. An open circuit or a resistance reading outside the expected range for that heater confirms a failed heating element. If heater resistance checks out within spec, attention should shift to the RD-S termination sensor and its wiring harness, checking for continuity, correct resistance-to-temperature response, and secure connector seating at the control board.

Source: manufacturer service documentation.

Common causes of r3

  1. 01

    Failed defrost heater

    Part replacement

    The defrost heater assembled with the evaporator coil may have gone open-circuit or developed abnormal resistance, preventing it from generating enough heat to complete the defrost cycle. Measuring resistance across both heater terminals is the first step to confirm this failure.

  2. 02

    Defective defrost termination sensor (RD-S)

    Part replacement

    The RD-S sensor is responsible for signaling the end of the defrost cycle once the evaporator reaches the correct temperature. If this sensor has failed or is reading inaccurately, the control board never receives the termination signal and the cycle runs until the 50-minute limit is reached.

  3. 03

    Wiring harness or connector fault

    Wiring / connection

    Damaged wiring or loose connectors between the defrost heater, the RD-S sensor, and the control board can interrupt circuit continuity and mimic component failures. Inspect the harness for corrosion, pinching, or unseated connectors before replacing parts.

  4. 04

    Faulty defrost control board

    Part replacement

    If the heater and sensor both test within specification, the main control board or defrost control module may not be correctly initiating or monitoring the defrost cycle. This is a less common cause but should be considered after ruling out the heater and sensor.

  5. 05

    Excessive frost buildup causing prolonged defrost demand

    Wiring / connection

    A heavily iced evaporator due to a door seal leak or repeated door openings may require more time than the 50-minute limit allows to fully defrost, triggering the time-limit cutoff even with otherwise functional components. Check door gaskets for tears or gaps as part of the diagnosis.

See the test procedure for each cause

Frequently asked questions about r3

What does r3 mean on a Bosch refrigerator?
The r3 code means the refrigerator compartment defrost cycle did not complete normally. Instead of ending through the defrost termination sensor (RD-S), the cycle ran until the 50-minute safety time limit was reached and was cut off automatically. This points to a problem with the defrost heater, the RD-S termination sensor, or the wiring connecting them to the control board.
How do I fix the r3 error code on my Bosch refrigerator?
Start by measuring the resistance across both terminals of the defrost heater, which is assembled directly with the evaporator coil. An open circuit reading confirms a failed heater that needs replacement. If the heater tests correctly, check the defrost termination sensor (RD-S) for proper resistance and continuity, and inspect all related wiring and connectors for damage or loose connections.
Will resetting my Bosch refrigerator clear the r3 error?
A reset may temporarily clear the r3 code from the display, but it will not resolve the underlying fault. If the defrost heater or termination sensor is defective, the error will return the next time a defrost cycle is initiated. A proper repair of the faulty component is required to permanently clear the code.
Is it safe to keep using my refrigerator while it shows the r3 error?
Continued use with an active r3 error can allow ice to accumulate on the evaporator coils, which will progressively reduce cooling performance and may eventually block airflow entirely. While the refrigerator is not immediately dangerous to operate, food spoilage is a real risk if cooling becomes significantly impaired. Addressing the fault promptly is recommended.
How much does it cost to repair a Bosch refrigerator r3 error?
Repair costs depend on which component has failed. A replacement defrost heater typically ranges from $30 to $80 for the part, while a defrost termination sensor generally costs between $15 and $50. Adding professional labor, total repair costs often fall in the range of $100 to $250 depending on your location and the technician's rates.

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