Airbag control unit with part number P8635A251

What does the airbag control unit P8635A251 do?

The airbag control unit P8635A251 is the central control unit of the restraint system (SRS) for Mitsubishi. It evaluates the signals from the crash sensors and, in the event of an accident, decides within fractions of a second which airbags and seatbelt pretensioners are triggered.

The unit also monitors the entire system continuously. If it detects a fault, it shows it via the airbag warning light in the instrument cluster, so the driver can recognise a malfunction.

After an accident, the control unit stores crash data and locks itself. Only a repair lifts this lock. In everyday use, the electronics work unobtrusively in the background.

Why does the control unit P8635A251 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed. An ordinary diagnostic tool cannot erase this data. Aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes are also possible causes.

Crash data is created as soon as the control unit registers an accident event. An airbag does not need to have deployed for this. The entries remain in memory even if the vehicle appears undamaged from the outside.

The other causes are of a more general nature. Electronic components age, solder joints can become weak points, and moisture or corrosion attack plug connections. A weak battery or a jump start can also cause voltage spikes that affect the electronics.

How can you tell that the P8635A251 is defective?

The airbag warning light in the instrument cluster lights up permanently or intermittently. In addition there is a fault message in the instrument cluster, the diagnostic tool has no connection to the control unit, and a fault memory that cannot be cleared.

The warning light is a central sign, because it reports faults in the restraint system directly on the dashboard. Respond to it promptly, because in an emergency the airbags and seatbelt pretensioners may fail to deploy.

A missing connection to the diagnostic tool is also a clear indication. In that case a precise check is needed to narrow down the cause.

Which vehicles is the P8635A251 fitted in?

The control unit P8635A251 is fitted in these vehicles: Mitsubishi Lancer CY (2007-2017). This assignment helps you check, before removal, whether the unit suits your car.

The following list shows the vehicles for which this unit is recorded.

• Mitsubishi Lancer CY (2007-2017)

First compare the part number on the label of the removed unit with this page. This only establishes that it is the right unit. Also have the fault memory read out, because only this result shows whether the control unit itself is defective or a plug or cable is the cause.

For the same vehicles, we also repair control units with the part numbers P8635A146, P8635A168, TARME1308R0924, TARME2937R0152.

How does the repair of the P8635A251 work?

First have the fault memory read out and enclose the log; only then disconnect the battery and remove the control unit. Airbag24 checks, repairs and tests the unit and erases the crash data. Processing usually takes 3–4 working days.

On your side, the order is important: read out, disconnect the battery, then remove. Afterwards, create a repair order online and send in the well-packed unit.

Airbag24 checks the unit on the test bench, replaces defective components and erases stored crash data. A function test follows, and then your own unit is returned 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 P8635A251 get to Airbag24?

You send the control unit P8635A251 as a parcel, or for an extra charge you book a UPS collection. After the repair, Airbag24 returns it by UPS.

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