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Error code reference

Bosch Refrigerator Error Code u1

V-sensor (Vita sensor) disconnection or short circuit.

Bosch codesBosch refrigerator codes

V-sensor (Vita sensor) disconnection or short circuit.

First step from the service manual

Measure the resistance between both terminals after separating CN14 of the Main PCB. If V-sensor is disconnected or shorted, change the V-sensor in the fridge compartment.

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

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What u1 means on a Bosch refrigerator

The U1 error code on a Bosch refrigerator indicates a fault with the V-sensor, also called the Vita sensor, located in the refrigerator compartment. This sensor is responsible for monitoring specific environmental conditions within the fridge compartment, and the U1 code is triggered when the main PCB detects either a disconnection or a short circuit in the sensor circuit. The fault is confirmed by measuring resistance across both terminals of the sensor after disconnecting connector CN14 from the main PCB.

A disconnection fault occurs when the circuit between the Vita sensor and the main PCB is broken, resulting in an open circuit with no measurable resistance. A short circuit fault, by contrast, occurs when the sensor or its wiring creates an unintended low-resistance path between the two terminals. Both conditions prevent the PCB from receiving a valid signal, triggering the U1 alert. The diagnostic process involves physically separating CN14 from the main PCB and using a multimeter to measure resistance across the sensor terminals.

If the resistance reading confirms either an open circuit or a short, the V-sensor itself must be replaced in the refrigerator compartment. In some cases, the wiring harness connecting the sensor to CN14 may be the source of the fault rather than the sensor body itself, so inspecting the harness for damage, corrosion, or loose connections before replacing the sensor is a reasonable first step.

Source: manufacturer service documentation.

Common causes of u1

  1. 01

    Failed V-sensor (Vita sensor)

    Part replacement

    The Vita sensor itself may have developed an internal short circuit or open circuit, preventing it from sending a valid signal to the main PCB. Resistance measurement across the sensor terminals after disconnecting CN14 will confirm this if the reading shows zero or infinite resistance.

  2. 02

    Disconnected or loose wiring harness

    Wiring / connection

    The connector or wiring between the Vita sensor and CN14 on the main PCB may have come loose, been pinched, or pulled free. Inspect the harness along its full length for any visible separation or loose fit at either connection point.

  3. 03

    Damaged wiring harness

    Part replacement

    The wire harness running from the Vita sensor to the main PCB may be cut, frayed, or corroded, creating an open or shorted circuit. Physical damage from ice buildup, sharp edges, or pest activity can cause this type of fault.

  4. 04

    Corroded or damaged CN14 connector

    Wiring / connection

    Moisture or oxidation at the CN14 connector on the main PCB can cause poor contact, mimicking a disconnected sensor. Inspect the connector terminals for discoloration, corrosion, or bent pins before replacing the sensor.

  5. 05

    Faulty main PCB

    Part replacement

    If the Vita sensor and all wiring test correctly, the main PCB may be misreading the sensor circuit due to a board-level fault. This is the least likely cause and should only be considered after the sensor and harness have been ruled out.

See the test procedure for each cause

Frequently asked questions about u1

What does u1 mean on a Bosch refrigerator?
The U1 error code on a Bosch refrigerator indicates that the main PCB has detected a disconnection or short circuit in the V-sensor, also known as the Vita sensor, located in the refrigerator compartment. The code is triggered when the sensor signal falls outside the expected range due to an open or shorted circuit. Diagnosing the fault requires measuring resistance at the sensor terminals after disconnecting the CN14 connector from the main PCB.
Can I fix the U1 error on my Bosch refrigerator myself?
A knowledgeable DIYer comfortable with basic electrical testing can diagnose this fault by disconnecting CN14 from the main PCB and using a multimeter to check resistance across the Vita sensor terminals. If the sensor is confirmed faulty, replacing it in the refrigerator compartment is a straightforward repair. However, if the issue involves the main PCB or internal wiring harness, a qualified technician is recommended.
Is it safe to keep using my Bosch refrigerator when it shows the U1 error?
The U1 error indicates a sensor monitoring fault, which means the refrigerator may not be accurately tracking conditions in the fridge compartment. While the refrigerator may continue to run, food safety could be at risk if the appliance is not maintaining proper temperatures without accurate sensor feedback. It is best to have the fault addressed promptly rather than continuing to rely on the appliance.
Will resetting my Bosch refrigerator clear the U1 error code?
A simple power reset is unlikely to permanently clear the U1 error because the code is caused by a physical fault, either a disconnection or short circuit in the Vita sensor circuit. The error will return as soon as the main PCB attempts to read the sensor again. The underlying sensor or wiring issue must be repaired or the sensor replaced before the code will clear and stay clear.
How much does it cost to repair a Bosch refrigerator U1 error?
Repair costs depend on whether the fault is in the Vita sensor, the wiring harness, or the main PCB. Sensor replacement is typically the least expensive fix, with parts costs generally ranging from around $30 to $80 and labor adding $75 to $150 depending on the service provider. If the main PCB is at fault, total repair costs can range from $200 to $400 or more including parts and labor.

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