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Electrical system and control unitsGeneric OBD-II codeUrgency: Garage soon

U0151 on BMW: causes and affected models

U0151 means: loss of communication with the restraint systems control module (airbag control unit).[1][2][3][4] BMW has 27 documented faults that can trigger it, across 22 models, including BMW iX I20, BMW Serie 1 F40, BMW X5 G05 and BMW X7 G07. Only a diagnosis can confirm the cause on your car.

Documented faults
27
that can trigger it
System
Electrical system and control units
BMW models
22
with at least one of these faults
Urgency
Garage soon

4 sourcesHow we work

Documented BMW faults that can trigger U0151

Grouped by engine or model, from most to least important. These are faults with the airbags: not all of them will necessarily set the code, and only a diagnosis confirms the cause on your car.

BMW iX I20

Common causes of U0151 on any make

From most to least likely, according to the sources.

  1. 1Connector under the seat (contacts for seat occupancy detection, side airbags and seatbelt pretensioners) loose or corroded. Dietrich considers this the most common cause.[1]
  2. 2Water or moisture ingress (through seals, blocked drains or spilt liquids) corroding the pins and plates.[1]
  3. 3Data line between the gateway and the airbag control unit interrupted or short-circuited, with sections of the harness chafed; RCM wiring in poor condition or damaged connections in its circuit (CódigosDTC).[1][2]
  4. 4Lack of power or earth to the airbag control unit: Dietrich warns that an earth fault gives the same symptoms as a faulty control unit.[1][3]

What to check first

The first diagnostic steps, from the most likely and cheapest to check to the most expensive.

  1. 1Read all the control units and see which ones report the airbag control unit as unreachable: that will tell you whether a single module or a whole branch of the bus is at fault. Check the model's technical bulletins.[1][2]
  2. 2Measure the power supply and earth of the airbag control unit. Dietrich points out that an earth fault gives the same symptoms as a faulty module.[1]
  3. 3Inspect the connectors, especially under the seats: corrosion, open contacts and moisture. Check the wiring and repair anything worn or burnt.[1][2]
Full guide to U0151: symptoms, diagnosis and whether you can drive

Frequently asked questions

Which BMW models have faults that can trigger U0151?

BMW iX I20 (3 faults), BMW Serie 1 F40 (2 faults), BMW X5 G05 (2 faults), BMW X7 G07 (2 faults), BMW i4 G26 (1 fault) and BMW i8 I12 (1 fault). Each fault has its own page with the affected years and versions, the symptoms and the repair cost.

What does code U0151 mean on a BMW?

Loss of communication with the restraint systems control module (airbag control unit). Another module in the car (the network gateway or another monitoring module) has stopped receiving the periodic messages from the restraint systems control module (RCM), the airbag control unit. According to the German workshop Dietrich, the code only reports that the data connection has been interrupted: it does not say that a particular airbag or pretensioner has failed. It is a generic OBD-II code: it means the same on a BMW as on any other make.[1][2][3][4]

Can I keep driving with U0151?

Garage soon. Only one of the sources gives its view on severity: the Dietrich workshop advises against driving with the code active, because the restraint system may be disabled or may not deploy in an accident, and asks for the airbag warning light to be treated as a priority. The car can move, but the prudent course is not to postpone the check, and not to clear the code without correcting the fault, as it will reappear.[1]

Sources

Every fact on this page links to its source. If you find an error, let us know.

  1. Fehlercode U0151: Lost Communication with Restraints Control Module (Airbag)Kfz-Meisterbetrieb Dietrich · Other source · consulted 31 October 2026 · in German
  2. U0151 - Se ha perdido la comunicación con el módulo de control de los sistemas de retenciónCódigosDTC · Technical documentation · consulted 31 October 2026 · in Spanish
  3. U0151 - Lost Communication With Restraints Control ModuleThe Automotive Technician (TaT) · Technical documentation · consulted 31 October 2026
  4. U0151 - Lost Communication With Restraints Control ModuleDTCSearch · Technical documentation · consulted 31 October 2026