Airbag control unit with part number 4H0907553E

What is the function of the airbag control unit 4H0907553E?

The airbag control unit with part number 4H0907553E is the central control module for the occupant protection system in Audi A8 and S8 D4 models. It is manufactured by Bosch (production code 441570500) and is responsible for processing sensor data and activating airbags and seatbelt pretensioners in the event of a crash.

The control unit 4H0907553E, often associated with Bosch numbers 0 285 010 856 or 0 285 011 977, serves as the brain of the passive safety system. It continuously collects data from various crash and acceleration sensors throughout the vehicle to accurately detect an accident situation.

In the event of a serious collision, the electronics decide within milliseconds whether to deploy the relevant restraint systems. These include front and side airbags, seatbelt pretensioners, and the pyrotechnic trigger for pedestrian protection, ensuring the safety of occupants and other road users.

Why does the control unit 4H0907553E fail?

The most common cause of failure for the control unit 4H0907553E is the storage of crash data after an airbag deployment, which prevents further use. Other causes include electronic malfunctions due to voltage fluctuations, water damage, or age-related wear of internal components, leading to internal errors.

After a crash in which airbags or seatbelt pretensioners have deployed, the control unit permanently stores so‑called “crash data.” This lockout is built into the design by the manufacturer and prevents reuse without professional repair. The unit becomes internally blocked and reports a permanent fault.

Besides crash data, defects in the internal electronics can also lead to failure. Voltage fluctuations in the vehicle’s electrical system, moisture ingress, or simply the aging of electronic components can impair functionality and result in non‑erasable error codes.

It is important to note that other Bosch part numbers such as 0285010856 or 0285011977 may also be installed in these vehicles and exhibit similar failure patterns. Therefore, carefully verifying the part number on the unit is essential.

How do you recognize a defect in the control unit 4H0907553E?

A defective airbag control unit 4H0907553E primarily manifests as a permanently illuminated airbag warning light on the instrument cluster. Additionally, specific diagnostic trouble codes cannot be cleared from the fault memory, or the control unit becomes unreachable by diagnostic equipment, indicating a communication error.

The clearest sign of a defect is the airbag warning light that remains on continuously or flashes intermittently on the dashboard. This indicates that the safety system is not fully operational and may fail to deploy correctly in the event of a crash.

During diagnostics, specific permanent error codes are often read out that cannot be reset. Typical entries include B100311 (ignition circuit 2 for the front passenger‑side airbag) or B103811 (ignition circuit for the pedestrian‑protection trigger), pointing to an internal fault within the control unit.

In some cases, the control unit has completely failed and can no longer be accessed via the diagnostic interface. The tester then reports “no communication,” making detailed fault analysis more difficult but clearly indicating a severe internal malfunction.

In which vehicles is the control unit 4H0907553E installed?

The airbag control unit 4H0907553E is specifically designed for Audi’s luxury segment. It is used in the Audi A8 of the D4 (4H) series as well as its sporty counterpart, the Audi S8 D4. This includes both pre‑facelift and facelift models of these generations.

At Airbag24, we repair the control unit 4H0907553E for the following specific vehicle models and model years:

Audi A8:

D4 4H (model years 2010–2013)

D4 4H Facelift (model years 2013–2017)

Audi S8:

D4 (model years 2012–2013)

D4 Facelift (model years 2013–2017)

As this is a safety‑critical component, correctly matching the part number to the vehicle model is crucial to ensure full functionality of the restraint system.

How is the 4H0907553E repaired?

Professional repair of the control unit 4H0907553E involves precise diagnostics, targeted elimination of the root cause—such as clearing crash data or replacing faulty components—and a final functional test. After restoration, the unit is fully operational and ready for installation.

Following removal and shipment to Airbag24, the control unit undergoes an initial inspection. Our technicians analyze the fault memory and identify the exact cause of the defect, whether it’s a stored crash data record or an electronic fault.

In the next step, the actual repair takes place. Stored crash data is reset at the processor level, and if necessary, defective electronic components are replaced with genuine parts. The control unit must be sent in unopened for repair.

Finally, each repaired control unit undergoes a comprehensive functional test to ensure it meets factory specifications. We provide a 12-month warranty on all repairs performed.

What shipping options does Airbag24 offer?

To send your defective control unit to Airbag24, you can ship it yourself free of charge, bring it in person, or arrange a convenient UPS pickup. For the return shipment, we offer free standard UPS shipping as well as optional express shipping, both with the option of cash-on-delivery.

You have flexible options for sending your removed control unit back to us. You can mail the package yourself, drop it off directly at our facility, or use our convenient UPS pickup service, which collects the package from your preferred location.

After successful repair, the return shipment is provided free of charge via standard UPS delivery, typically taking 1–3 business days.

If you need faster delivery, UPS express shipping (delivered in 1–2 business days) is available. Both standard and express shipping can optionally be combined with cash-on-delivery. Alternatively, you can pick up the repaired unit in person at our premises.