Airbag control unit with part number 985101865R

What does the airbag control unit 985101865R do?

With Smart, the airbag control unit 985101865R takes over control of the restraint system (SRS). It registers what happens in an accident via the crash sensors and decides within milliseconds which airbags and seatbelt pretensioners are triggered. It reports faults via the airbag warning light.

Outside of accidents, it monitors the system in the background. After an accident, it stores crash data and locks itself.

This lock is lifted exclusively by the repair.

Why does the control unit 985101865R fail?

Stored crash data is the most common cause of a failure, because it remains in the unit after an accident, even if no airbag has deployed. A standard diagnostic tool does not erase it. Other causes include aged electronics, cold solder joints, moisture and corrosion on plug connections, and voltage spikes.

Crash data is erased at Airbag24 during the repair.

Ageing and cold solder joints act unseen; moisture and corrosion attack the contacts. Voltage spikes, for example from a weak battery or a jump start, can additionally load the unit.

How can you tell that the 985101865R is defective?

A defect first shows up at the airbag warning light in the instrument cluster, which lights up permanently or intermittently. A fault message appears in the instrument cluster, and the diagnostic tool gets no connection to the control unit.

If the fault memory cannot be cleared, that is another sign of a fault.

Airbags and seatbelt pretensioners may then fail to deploy in an emergency, which is why this warning must be taken seriously.

Which vehicles is the 985101865R fitted in?

The models in which the 985101865R is fitted include: Smart Fortwo C453 (2014-2024).

The vehicles listed individually:

• Smart Fortwo C453 (2014-2024)

Comparing the part number with the label on the removed unit only confirms the identity of the unit. Whether the control unit is defective or a connector or cable is the cause is shown only by reading out the fault memory. Please have this carried out beforehand.

For the same vehicles, we also repair control units with the part numbers A453 901 89 00, A4539001702, A4539017400.

How does the repair of the 985101865R work?

At Airbag24, checking, repairing and testing the 985101865R usually takes 3–4 working days. This time frame applies only to the repair work.

A fixed sequence applies beforehand: have the fault memory read out and enclose the report, disconnect the battery, and only then remove the control unit. Then create the repair order online and send in the well-packed unit.

Airbag24 examines the unit on the test bench, fixes defective components and erases the crash data. A function test concludes the work, after which your own unit is sent back.

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 985101865R get to Airbag24?

A parcel or a UPS collection booked for an extra charge brings the control unit 985101865R to Airbag24. After the repair, the return follows by UPS.

Print the repair order, put it in the parcel and pack the unit shock-resistant.