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Error code reference

Bosch Refrigerator Error Code rD

RD-sensor (refrigerator defrost sensor) disconnection or short circuit.

Bosch codesBosch refrigerator codes

RD-sensor (refrigerator defrost sensor) disconnection or short circuit.

First step from the service manual

Measure the resistance between both terminals after separating CN15 of the Main PCB. If RD-sensor is disconnected or shorted, change the RD-sensor on the evaporator.

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

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What rD means on a Bosch refrigerator

The rD error code on a Bosch refrigerator indicates a fault with the RD-sensor, which is the refrigerator compartment defrost sensor. This sensor is mounted on the evaporator and monitors temperature during the defrost cycle to ensure the evaporator coil defrosts properly without overheating. When the control system detects that the RD-sensor circuit is either open (disconnected) or shorted, it triggers this code to alert the technician to a loss of accurate temperature feedback from that critical monitoring point.

The primary diagnostic procedure involves isolating the sensor electrically by separating connector CN15 from the Main PCB, then measuring resistance across both terminals of the sensor circuit. A disconnected sensor will show an open circuit with infinite or unmeasurably high resistance, while a shorted sensor will show near-zero resistance. Neither condition allows the control board to read a valid temperature signal, so the board flags the fault as rD.

If the resistance measurement confirms an open or shorted condition at the sensor itself, the RD-sensor mounted on the evaporator must be replaced. In some cases, the fault may originate in the wiring harness between CN15 and the sensor rather than the sensor body itself, so inspecting the connector pins and harness for damage, corrosion, or broken wires is an important part of the diagnostic before condemning the sensor.

Source: manufacturer service documentation.

Common causes of rD

  1. 01

    Failed RD-sensor on the evaporator

    Part replacement

    The defrost sensor itself has failed internally, resulting in an open or shorted circuit. Resistance measurement at CN15 will confirm this when the reading falls outside the expected range for a functional sensor.

  2. 02

    Loose or disconnected CN15 connector

    Wiring / connection

    The connector CN15 at the Main PCB may have worked loose over time due to vibration or handling, breaking the circuit to the RD-sensor. Reseating the connector firmly may resolve the fault if the sensor itself is undamaged.

  3. 03

    Damaged wiring harness between CN15 and the sensor

    Wiring / connection

    The wiring between the Main PCB connector and the evaporator-mounted sensor can develop breaks, cuts, or pinched sections, causing an open or intermittent circuit. Visually inspecting and testing continuity along the harness will identify this issue.

  4. 04

    Corroded or damaged connector pins at CN15

    Wiring / connection

    Moisture intrusion into the connector can corrode the terminal pins, increasing resistance or breaking continuity entirely. Inspecting CN15 for discoloration, pitting, or debris is a necessary step before proceeding to sensor replacement.

  5. 05

    Main PCB fault

    Part replacement

    If the wiring harness and RD-sensor both test within acceptable parameters, the Main PCB itself may be failing to correctly read the sensor circuit. This is the least common cause and should only be considered after all other components are ruled out.

See the test procedure for each cause

Frequently asked questions about rD

What does rD mean on a Bosch refrigerator?
The rD code means the refrigerator compartment defrost sensor (RD-sensor) has been detected as disconnected or shorted by the Main PCB. This sensor sits on the evaporator and tracks temperature during defrost cycles. The error indicates the control board is not receiving a valid signal from that sensor circuit.
Can I fix the rD error on my Bosch refrigerator myself?
A knowledgeable DIYer can start by checking that connector CN15 at the Main PCB is firmly seated and that the wiring harness running to the evaporator is not visibly damaged. If you have a multimeter, you can separate CN15 and measure resistance across the sensor terminals to determine if the sensor is open or shorted. Replacing the RD-sensor on the evaporator is a more involved repair that requires accessing the evaporator coil, so comfort with appliance disassembly is needed.
Is it safe to keep using my Bosch refrigerator while the rD code is showing?
Operating the refrigerator with an active rD code means the control system cannot properly monitor the defrost cycle, which can lead to ice buildup on the evaporator or inadequate defrost performance over time. Food safety could be compromised if cooling is affected as a result. It is best to address the fault promptly rather than continuing to run the appliance in a faulted state.
Will resetting the refrigerator clear the rD error code?
A power reset may temporarily clear the displayed code, but the error will return if the underlying fault with the RD-sensor circuit has not been corrected. The Main PCB monitors the sensor continuously, so any persistent open or short condition will trigger the code again during normal operation. The sensor or wiring issue must be diagnosed and repaired for the code to clear permanently.
How much does it cost to repair a Bosch refrigerator rD error?
If only the RD-sensor needs replacement, parts typically range from around $20 to $60 depending on the specific Bosch model, with professional labor adding $80 to $150 or more depending on your region. If the fault turns out to be a damaged wiring harness, costs may be lower if the harness can be repaired rather than replaced. A Main PCB replacement, if required, would be the most expensive outcome, with parts alone ranging from $150 to $400 or higher.

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