Aston Martin DB9 VH airbag control unit repair

What is an Aston Martin DB9 VH airbag control unit?

When you switch the ignition on, the airbag warning light comes on briefly and then goes out: this is the self-test of the airbag control unit in the Aston Martin DB9 VH running. This unit is the central control unit of the restraint system (SRS): in an accident, it decides within milliseconds whether the airbags and seatbelt pretensioners fire.

This decision is based on the signals from the crash sensors, which the control unit evaluates continuously. At the same time it monitors the entire system during operation and indicates a detected fault via the airbag warning light. After an accident it stores crash data and locks itself.

The unit is installed in the Aston Martin DB9 VH (2004 to 2016). If the light does not go out after starting, the self-test has found a fault, or the control unit no longer responds at all. In both cases you should look into the cause, because the restraint system is then not reliably ready for use.

Why is the Aston Martin DB9 VH airbag control unit defective?

Most often it is crash data left in the unit by an accident, even when the airbags did not deploy at all. Other possible causes are electronic components with age-related damage, cold solder joints, corrosion and moisture at the connectors, or voltage spikes, for example with a weak battery or after a jump start.

A permanently lit airbag warning light, a fault memory that cannot be cleared, or a diagnostic tool that cannot connect all point to a problem. Stored crash data cannot be removed by an ordinary diagnostic tool, not even after an accident in which no airbag was triggered.

A vehicle that has never been in an accident is no proof to the contrary. The electronics can age without any accident, moisture can get in, and overvoltage in the vehicle electrical system can damage components. Which cause applies to your unit only becomes clear during the inspection.

Common error codes for Aston Martin DB9 VH airbag control unit repair

The reported codes point to internal component faults in the control unit, failed communication with other systems, problems with the power supply, or stored crash events. They become visible through a diagnostic tool on the Aston Martin DB9 VH.

We know these messages for the airbag control unit of this model; others may occur. Next to each one you will find what the code indicates.

• 0132 → Internal component fault, initialisation failed
• 0131 → Internal component fault, initialisation failed
• CFFF → Internal fault of the restraint system control unit
• 013B → Several crash events stored in the crash memory
• 0128 → Configuration signal from the central electronics failed
• 0005 → Battery voltage too low
• 0006 → Battery voltage too high
• 0156 → Supply voltage to the central electronics deviates

You need to read out the fault memory with a diagnostic tool to see the codes. A single code does not necessarily mean that the control unit has actually failed: connectors, wiring or a connected airbag module may equally be the cause. Where the fault lies is only established by the inspection.

What part numbers are available for the Aston Martin DB9 VH airbag control unit repair?

The part number is printed on the label on the unit and defines the exact version. Because the numbers within a model series differ by equipment and year of production, you should read it directly from your unit.

Numbers known to us for the Aston Martin DB9 VH are shown in the list below; it is not complete.

• 30773787
• 30795181
• 30773786
• 31334739

Hold the number of your unit next to this list. A match only shows that it is the matching unit; whether it is defective only becomes clear when the fault memory is read out or during the inspection.

This is how you get to the repair: first have the fault memory read out. Then disconnect the battery from the vehicle electrical system and remove the control unit. After that, create a repair order online and send in the unit. Inspecting, repairing and testing at Airbag24 usually take 3–4 working days. The repaired control unit comes back with all vehicle data and is ready for use as soon as it is refitted — no coding or programming is required.