Airbag control unit with part number 1J0 909 603 E

What does the airbag control unit 1J0 909 603 E do?

The airbag control unit 1J0 909 603 E is the central control unit of the restraint system (SRS) for Volkswagen. It evaluates the signals from the crash sensors, decides in an accident within milliseconds which airbags and seatbelt pretensioners are triggered, and monitors the system continuously.

The unit detects faults itself and reports them via the airbag warning light in the instrument cluster. This keeps the state of the system visible to you in everyday life.

After an accident the control unit stores crash data and locks itself. This lock is lifted only by the repair of the unit.

Why does the control unit 1J0 909 603 E fail?

The most common cause is stored crash data: it remains in the unit after an accident, even if no airbag has deployed, and a normal diagnostic tool cannot remove it. Other causes include aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes, for example from a weak battery or jump-starting.

The crash data record the impact and remain even if the vehicle shows hardly any visible damage from outside.

The other causes develop over a longer period. Moisture and corrosion attack the contacts and disrupt signal transmission, while voltage spikes occur suddenly and load the electronics.

How can you tell that the 1J0 909 603 E is defective?

A defect shows up on the airbag warning light in the instrument cluster, which stays on permanently or intermittently, on a fault message in the instrument cluster, on a diagnostic tool that has no connection to the control unit, or on a fault memory that cannot be cleared. In an emergency, airbags and seatbelt pretensioners may then possibly not deploy.

• airbag warning light stays on permanently or intermittently
• fault message in the instrument cluster
• diagnostic tool finds no connection to the control unit
• fault memory cannot be cleared

If the light comes on, have the system checked promptly. Do not wait for the display to resolve itself, because it signals a fault that persists.

Which vehicles is the 1J0 909 603 E fitted in?

This part number is linked to vehicles with us. The control unit 1J0 909 603 E is fitted in these vehicles: Volkswagen Transporter T4 (1990-2003).

The vehicles known to us for this part number are listed here.

• Volkswagen Transporter T4 (1990-2003)

Compare the part number on the label of the removed unit with this page; that only confirms that it is the correct unit. Also have the fault memory read out in advance, because this 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 1J0 909 603, 1J0 909 603 AH, 6N0 909 603 S.

How does the repair of the 1J0 909 603 E work?

First read out the fault memory and attach the log. Then disconnect the battery, and only after that remove the control unit. Next, create a repair order online and send the well-packed unit in. Airbag24 checks it on the test bench, replaces defective components, deletes the crash data and carries out a function test.

Processing at Airbag24 usually takes 3–4 working days. This period covers only checking, repairing and testing at Airbag24.

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 1J0 909 603 E get to Airbag24?

Send the control unit 1J0 909 603 E in as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

Enclose the printed repair order in the parcel and pack the unit shockproof, so that it survives transport undamaged.