Airbag control unit with part number P30773401

What does the airbag control unit P30773401 do?

In Volvo vehicles the airbag control unit P30773401 takes over control of the restraint system (SRS). It evaluates the crash sensors, decides within milliseconds in an impact which airbags and seatbelt pretensioners fire, and keeps the overall system under watch.

Faults are shown via the airbag warning light. After an accident the unit stores crash data and locks itself; only a repair lifts the lock.

The control unit is therefore the link between the sensors and the triggers in the restraint system.

Why does the control unit P30773401 fail?

Stored crash data from an accident is the most common cause, even if no airbag has deployed. Other causes include ageing electronics, cold solder joints, moisture and corrosion on plug connectors, and voltage spikes.

The crash data remains in the control unit, even if no airbag was triggered during the event. An ordinary diagnostic tool cannot remove it.

Ageing components and cold solder joints cause intermittent faults that only gradually become noticeable. Moisture and corrosion on plug connectors create contact problems.

Voltage spikes, for example from a weak battery or jump starting, add further strain on the electronics.

How can you tell that the P30773401 is defective?

The airbag warning light lights up constantly or intermittently, and an error message appears in the instrument cluster. In addition there are cases in which the diagnostic tool cannot connect or the fault memory cannot be cleared.

• Airbag warning light constantly or intermittently on
• Error message in the instrument cluster
• No connection can be established to the diagnostic tool
• Fault memory cannot be cleared

As long as these signs are present, airbags and seatbelt pretensioners may not deploy in an emergency. Therefore, have the fault cleared promptly.

Which vehicles is the P30773401 fitted in?

The P30773401 is fitted in these vehicles: Volvo S40 M (2004-2007) and M Facelift (2007-2012).

The overview below shows the vehicles we have on record for this control unit.

• Volvo S40 M (2004-2007)
• Volvo S40 M Facelift (2007-2012)

You should compare the part number on the label with this page before removal; this only confirms the correct unit. Have the fault memory read out beforehand, because it shows whether the control unit itself or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 30773401, 31334738, P30724427, P30724652, P30773354, P31295109.

How does the repair of the P30773401 work?

The repair begins with having the fault memory read out and enclosing the log. This is followed by disconnecting the battery, removing the unit and creating a repair order online. Processing at Airbag24 usually takes 3–4 working days.

At Airbag24 the unit is tested, defective components are replaced, the crash data is erased and a function test is run. The unit is then returned to you.

The 3–4 working days apply solely to this work with us. Our repairs come with 2 years' statutory liability for defects. 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.

How does the control unit P30773401 get to Airbag24?

You either send the control unit as a parcel, or you book a UPS collection for an extra charge. After the repair, Airbag24 returns it by UPS.

Enclose the printed repair order and make sure the packaging is shock-resistant.