Airbag control unit with part number A1669001211

What does the airbag control unit A1669001211 do?

The airbag control unit A1669001211 controls the restraint system (SRS) in Mercedes-Benz vehicles. In an emergency it evaluates the signals from the crash sensors and decides within milliseconds which airbags and seatbelt pretensioners trigger. It reports faults via the airbag warning light in the instrument cluster.

While driving, monitoring runs without interruption. The unit checks sensors, wiring and supply voltage and records irregularities in its memory so that they can be read out later. The manufacturer's number Bosch 0285012023 is also printed on the housing.

After an accident the unit stores crash data and then remains locked. This lock is lifted only by the repair that Airbag24 carries out on the unit. Until then the control unit stays in this state, regardless of how the vehicle seems in everyday use.

Why does the control unit A1669001211 fail?

The most common cause is crash data stored after an accident, even if no airbag was triggered. Other causes are ageing electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

Crash data cannot be erased with a normal diagnostic tool, and that is exactly why the fault persists. The other causes concern ageing, contacts and the power supply. Voltage spikes arise, for example, from a weak battery or when a jump start is connected.

Which of these causes applies in an individual case only becomes apparent during the check in the workshop. Until then, a fault alone does not allow a reliable conclusion about the trigger.

How can you tell that the A1669001211 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently. In addition, an error message appears in the instrument cluster, the diagnostic tool finds no connection to the control unit, and the fault memory cannot be cleared.

If these signs appear, airbags and seatbelt pretensioners may in an emergency not trigger. The warning light shows the fault, and that is why it deserves attention as soon as it comes on.

Because the car can keep running unobtrusively in everyday use, it is worth keeping an eye on the warning light when you get in and while driving.

Which vehicles is the A1669001211 fitted in?

The A1669001211 is fitted, among others, in these vehicles: Mercedes-Benz ML-Class W166 SUV (2011-2015); Mercedes-Benz GLE-Class W166 SUV (2015-2018).

The following overview shows the model series and years of construction in which this unit was used.

• Mercedes-Benz ML-Class W166 SUV (2011-2015)
• Mercedes-Benz GLE-Class W166 SUV (2015-2018)

On the one hand, compare the part number on the label of the removed unit with this page. This only ensures that it is the right unit. On the other hand, have the fault memory read before removal, because only this result shows whether the control unit is defective or whether a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers A 166 900 39 03, A1669000220, A1669001709, A1669002003, A1669002713.

How does the repair of the A1669001211 work?

First have the fault memory read and attach the log. Then disconnect the battery and only then remove the control unit. Processing at Airbag24, meaning checking, repairing and testing, usually takes 3–4 working days.

Afterwards you create a repair order online and send the unit in well packed. Airbag24 checks it on the test bench, replaces defective components, erases the crash data and carries out a function test. Then Airbag24 sends the unit back to you.

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 A1669001211 get to Airbag24?

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

Place the printed repair order in the parcel and pack the unit shock-resistant.