00654-002 airbag control unit fault

What does error code 00654-002 mean?

Error code 00654-002 indicates a specific electrical fault in the driver-side seatbelt pretensioner circuit. The error description “Lower Limit Not Reached” means that the airbag control unit is detecting an excessively low resistance value or an open circuit, which prevents the pretensioner from functioning correctly in the event of a crash.

The airbag control unit continuously monitors the resistance values of all connected pyrotechnic components, including the seatbelt pretensioners. Each circuit must maintain a defined resistance level. If this value falls below the manufacturer’s specified threshold, the control unit interprets it as a critical fault, as the pretensioner’s ignition charge can no longer be reliably triggered.

As a safety precaution, the affected seatbelt pretensioner is deactivated, and error code 00654-002 is stored in the control unit’s fault memory. At the same time, the airbag warning light on the instrument cluster illuminates to alert the driver to the malfunction in the safety system.

How do you recognize error code 00654-002?

The primary and unmistakable symptom of error code 00654-002 is the permanently illuminated airbag warning light in the cockpit. This light does not extinguish after starting the vehicle, indicating an active, safety‑relevant fault in the system. Reading the fault memory confirms the specific code.

The airbag warning light serves as direct notification to the driver that the control unit’s self‑diagnosis has detected a malfunction. This signal should never be ignored, as the protective function of the airbag system—particularly the driver’s seatbelt pretensioner—is compromised.

Another characteristic is that the error code cannot be permanently cleared using standard diagnostic tools. Since this is a hardware fault in the circuit, the error reappears immediately after attempting to clear it, unless the physical cause is resolved.

What causes error code 00654-002?

The main cause of error code 00654-002 is resistance deviations in the wiring leading to the driver’s seatbelt pretensioner. Typically, these result from open or broken wires, contact issues at connectors, or mechanical damage to cables and plugs, all of which alter the electrical resistance of the circuit.

Specific electrical problems include broken wires, corroded contacts at connectors, or defective cable connections. These conditions cause the circuit’s resistance to fall outside the manufacturer‑specified tolerance range.

Mechanical defects are also a common cause. In three‑door vehicles, connector assemblies beneath the seat can become damaged due to repeated seat adjustments. Additionally, the coil spring in the steering wheel, subjected to constant stress with every steering movement, may suffer cable breakage and trigger this error.

Which vehicles are affected by error code 00654-002?

Error code 00654-002 primarily occurs in certain luxury Bentley models. It mainly affects vehicles from the 1990s through the 2010s, where this particular control unit architecture and wiring were used. Repairing this issue is especially cost‑effective for these exclusive vehicles.

At Airbag24, we repair error code 00654-002 for the following specific vehicle models and series:

Bentley Azure, 1st Generation (model years 2006–2011)

Bentley Continental T, 1st Generation (model years 1991–2002)

Bentley Continental Supersports Mk1

How is error code 00654-002 professionally repaired?

Professional repair begins with a thorough diagnosis of the fault within the vehicle to pinpoint the exact source of the problem in the seatbelt pretensioner circuit. After removal and shipment of the control unit, Airbag24 conducts a detailed analysis and restoration of the affected electrical components. Final testing ensures full functionality.

Upon receipt at Airbag24, the control unit is first scanned using specialized equipment to confirm error code 00654-002 and identify any stored crash data. A visual inspection of the circuit board and connections follows.

The actual in‑vehicle repair focuses on addressing the root cause. This includes checking all connection lines to the driver’s seatbelt pretensioner, performing precise resistance measurements within the circuit, and repairing or replacing damaged cables, connectors, and contacts. Upon completion, sensor calibration is often required.

After successful repair, the control unit undergoes testing on a test bench to verify proper communication and operation. This ensures a plug‑and‑play solution for the local workshop. We provide a 12‑month warranty on all repairs performed.