Airbag control unit with part number A1728200526

What does the airbag control unit A1728200526 do?

The airbag control unit A1728200526 is the central control unit of the SRS for Mercedes-Benz. It checks the crash sensors continuously and decides within milliseconds in an accident which airbags and seatbelt pretensioners are triggered.

It reports faults via the airbag warning light. After an accident it stores crash data and is locked afterwards.

Only the repair lifts this lock.

Why does the control unit A1728200526 fail?

The most common cause is stored crash data after an accident, even if no airbag was triggered. A normal diagnostic tool cannot erase it; Airbag24 removes it during the repair. Other causes are aged electronic components, cold solder joints, moisture and corrosion on plug connections, and voltage spikes, such as from a weak battery or jump-starting.

Crash data being present does not necessarily mean that an airbag has deployed.

Electronics age, solder joints can become cold over time, and moisture attacks contacts.

How can you tell that the A1728200526 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently, and a fault message appears in the display. The diagnostic tool gets no connection to the control unit, and the fault memory cannot be cleared.

• Warning light on permanently or intermittently
• Fault message in the instrument cluster
• No connection between diagnostic tool and control unit
• Fault memory cannot be cleared

In that case airbags and seatbelt pretensioners may not trigger in an emergency. The warning is therefore to be taken seriously.

Which vehicles is the A1728200526 fitted in?

The A1728200526 is fitted in these vehicles: Mercedes-Benz SLK-Class R172 Convertible (2011-2016); Mercedes-Benz SLC-Class R172 Convertible (2016-2020). The information refers to the assignment of this part number.

The following vehicles are assigned:

• Mercedes-Benz SLK-Class R172 Convertible (2011-2016)
• Mercedes-Benz SLC-Class R172 Convertible (2016-2020)

Comparing the part number on the label of the removed unit with this page only tells you that you have the correct unit. Have the fault memory read out beforehand, because only it shows whether the control unit is defective or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers A1729015704, A1729015805, A1729017601, A1729019102.

How does the repair of the A1728200526 work?

First have the fault memory read out and attach the log to the unit. Then disconnect the battery, afterwards remove the control unit and create a repair order online. Send in the unit, packed well.

At Airbag24 the unit is examined on the test bench. Repairing, testing and checking usually takes 3–4 working days. Defective components are replaced, stored crash data is erased and a function test is carried out, after which your own unit is returned.

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 A1728200526 get to Airbag24?

The unit reaches Airbag24 as a parcel, or UPS collects it for an extra charge. After the repair Airbag24 sends it back to you by UPS.

The printed repair order goes into the parcel, and the unit is packed shock-proof.