667 airbag control unit fault

What does error code 667 mean in the airbag control unit?

Error code 667 on a Volkswagen Golf 6 (5K1) indicates a serious internal fault in the airbag control unit. Typically, this is a hardware or software issue that puts the module into a locked state, prevents communication, and disables the entire airbag system.

Technically, this error signals that the control unit’s internal self-diagnosis has detected an irreparable inconsistency. The module can no longer guarantee its safety‑critical functions and therefore shuts down for safety reasons. Simply clearing the fault memory is not sufficient in this case.

Units with OEM part numbers 5C0959655B or 5C0959655C—supplied by Bosch (e.g., 5WK44286, 5WK44285)—are frequently affected. Thus, the fault is directly tied to a specific hardware generation.

How do you recognize error code 667?

The primary and unmistakable symptom is a permanently illuminated airbag warning light on the instrument cluster. Additionally, communication with the control unit via a diagnostic tool often fails, complicating diagnosis and pointing to a deep‑seated internal fault.

The airbag warning light remains on after starting the vehicle and does not extinguish as usual—clear evidence of an active, safety‑critical fault in the restraint system.

When attempting to read the fault memory, workshops often find that no communication can be established with the airbag control unit. The module does not respond to diagnostic requests, as if disconnected from the vehicle network.

In some cases, limited communication may still be possible, but accompanying error codes such as B1000 (control unit communication error) or FFFF (65535), indicating a general control unit failure, confirm the underlying issue.

What causes error code 667?

The main cause of error code 667 is an internal hardware defect on the airbag control unit’s circuit board, often due to faulty components or power supply problems. This frequently results in the unit being locked, signaled by error codes B10A1B or B200000.

Internal defects on the circuit board are the most common source of failure. These can arise from aging electronic components, microscopic cracks in solder joints, or malfunctions in microprocessors and memory chips. An accident is not necessarily required for this error to occur.

Error 667 often appears in combination with other specific codes. Errors B1000 (communication error), B10A1B, and B200000 (airbag control unit locked) directly indicate the internal lockout condition. The generalized fault code FFFF (65535) confirms an unspecified hardware or software failure.

In rarer cases, unstable power supply can trigger or exacerbate the fault, which may manifest as the accompanying error code FC 00532 (supply voltage too low).

On which vehicles does error code 667 occur?

In this specific context, error code 667 is primarily associated with the Volkswagen Golf 6. Airbag24 specializes in repairing affected airbag control units for this model, offering a cost‑effective alternative to expensive new parts.

At Airbag24, we repair error code 667 and its related symptoms for the following model:

Volkswagen: Golf 6 (Type 5K1), particularly models manufactured between 2008 and 2012.

For successful repair, precise identification of the part number (e.g., 5C0959655B or 5C0959655C) is crucial to ensure compatibility and proper functionality after installation.

How is error code 667 repaired?

Professional repair of error 667 involves purely electronic work on the removed control unit. At Airbag24, the module is analyzed at the component level; defective hardware parts are replaced, and the software is restored to its original state to fully restore functionality.

Upon submission to Airbag24, the control unit undergoes a comprehensive incoming inspection. Technicians read the internal memory to pinpoint the exact cause of the fault—whether it’s a hardware defect or corrupted crash data.

Repair procedures include both hardware and software interventions. Defective electronic components on the circuit board are expertly replaced, and voltage stability is restored. Simultaneously, the device’s software is reprogrammed, returning the module to factory settings.

Subsequently, the repaired control unit undergoes a thorough functional test on a test bench. Only when all functions are flawless is the unit approved for return shipment. We provide a 12-month warranty on every repair.