00654-007 airbag control unit fault

What does error code 00654-007 mean in the airbag control unit?

Error code 00654-007 indicates a specific electrical fault in the vehicle’s safety system. It points to a short circuit to vehicle ground in the driver-side seatbelt pretensioner circuit (component N153). This malfunction compromises the entire airbag system’s functionality and requires immediate technical inspection.

The seatbelt pretensioner is a pyrotechnic component that, in the event of a collision, instantly tightens the seatbelt to optimally position the occupant in the seat. A short circuit in this system means that electrical current takes an unintended path to the vehicle body ground instead of following its intended circuit.

As a result, the airbag control unit cannot properly monitor the pretensioner’s status nor reliably activate it during a crash. The “007” suffix in the error code specifies the fault type as “short to ground,” providing precise diagnostic information for technicians.

How can you recognize error 00654-007?

The primary and unmistakable symptom of error 00654-007 is the permanently illuminated or flashing airbag warning light on the instrument cluster. This warning indicates an active, safety‑critical fault in the restraint system. With this active fault, the airbag system’s operational safety is no longer guaranteed.

The warning light does not extinguish after starting the vehicle, as would normally occur during a routine system check. Instead, it remains continuously lit to alert the driver to the issue.

When reading the fault memory with a suitable diagnostic tool such as VCDS, error code 00654-007 is clearly displayed along with the description: “Seat Belt Pretensioner; Driver Side (N153) - Short to Ground.” Other vehicle‑related symptoms typically do not appear.

What causes error code 00654-007?

The root cause of error code 00654-007 is usually a hardware defect in the driver-side seatbelt pretensioner circuit. Common issues include damaged cables, corroded connectors, or an internal fault within the pretensioner itself. Less frequently, a defect in the airbag control unit’s circuit board may be responsible.

External sources of failure include crushed, frayed, or broken wiring—particularly in areas beneath the driver’s seat or near the B‑pillar. Corroded contacts at the pretensioner connector, often due to moisture ingress, can also trigger the short circuit.

An internal defect within the pretensioner itself is another possible cause. In rare cases, the airbag control unit may generate the error—for example, due to water damage, corrosion on the circuit board, or microcracks in the solder joints of the relevant driver module.

A crucial diagnostic step in the workshop is disconnecting the connector at the pretensioner. If the error code changes from “Short to Ground” (e.g., 29-00) to “Resistance Too High” (e.g., 32-00), this strongly suggests that the fault lies within the pretensioner itself rather than in the supply line from the control unit.

Which vehicles are affected by error 00654-007?

Error code 00654-007 has been specifically documented in certain Bentley models. Primarily affected are older‑generation luxury vehicles featuring a unique airbag system architecture. The installed control units often come from manufacturers such as Bosch or TRW.

At Airbag24, we have extensive experience repairing this fault and service control units for the following models:

Bentley Azure 1st Generation (2006–2011) Bentley Continental T 1st Generation (1991–2002) Bentley Continental Supersports Mk1

Since these control unit types may also be used in other vehicles, individual case-by-case verification is always advisable.

How is error 00654-007 repaired?

Professional repair begins with a thorough diagnosis of the vehicle to precisely locate the source of the fault. If the control unit is identified as the culprit, it is removed and sent in for repair. There, a detailed analysis and component‑level restoration ensures full functionality is restored.

Before removing the control unit, for safety reasons, it is mandatory to disconnect the vehicle battery for at least 15 minutes. This ensures the system is de‑energized and prevents any unintended activation of airbags or seatbelt pretensioners.

After being shipped to Airbag24, the control unit undergoes a standardized repair process. First, the fault memory is read, and the circuit board is examined under a microscope for visible damage such as corrosion or defective solder joints.

Subsequently, the relevant components and solder joints are professionally re-soldered or replaced as needed. Following successful repair, the fault memory is completely cleared, and the unit is thoroughly tested for proper functionality. Airbag24 provides 2 years' statutory liability for defects on the completed repair.