Air Bag Systems: Description and Operation

The air bag system is designed to supplement protection offered by seat belts in a frontal impact collision.

The Airbag system is equipped with On Board Diagnostic capability.System components are monitored electrically, and any malfunctions in operation can be detected. These malfunctions are then stored in the airbag control module memory, which can differentiate between 12 different types of malfunctions. After system diagnosis and servicing, the airbag control module DTC memory can be erased.

The airbag Malfunction Indicator Lamp (MIL) in the instrument cluster will come on when a malfunction is detected. A sporadic malfunction will also register.

If the airbag has been deployed, the system will indicate whether the deployment was correct (crash data), and which malfunction occurred at the time of deployment.

NOTE: CRASH DATA CANNOT BE ERASED.

VAG1551 Scan Tool (ST) functions in the following modes:
1. Rapid data transfer
2. Blink code output
3. Self test
4. Operating code (dealership identifier)

"Rapid data transfer" operating mode 1 permits checking the contents of DTC memory, and testing via the output Diagnostic Test Mode (DTM) using the VAG1551 scan tool.

"Blink code output" operating mode 2 cannot be used for checking Airbag II DTC memory.

Operating modes 3 and 4 concern only the scan tool and are described in the VAG1551 operating instructions.





WARNING: Read all Airbag II safety measures BEFORE doing any work on the airbag system

WARNING: DO NOT re-use any fasteners that are worn or deformed in normal use. Many fasteners are designed to be used only once and become unreliable and may fall when used a second time. This includes, but is not limited to, nuts, bolts, washers, self-locking nuts or bolts, circlips, and cotter pins. Always follow the recommendations given in this publication. For replacements always use new parts.

NOTE: Only use the VAG 1551 scan tool to test the driver and passenger side Airbag II system.

NOTE:
^ After switching the ignition on, the airbag Malfunction Indicator Light (MIL) will be illuminated for approximately 10 seconds.
^ If a malfunction or sporadic malfunction is detected, the indicator light will flash (blink) for approximately 25 seconds after 10 second check, then stay on steady.
^ When the MIL goes out, the system is functional.
^ Check using VAG 1551 scan tool if the airbag MIL does not go out after approx. 10 seconds, or if it does not come on (check bulb first).
^ If all indicator light checks are OK, check airbag system with VAG 1551 scan tool





1. Triggering unit
2. Steering wheel with airbag unit
^ Always set airbag unit down with horn pad facing UP
3. Connector for airbag spiral spring
4. Airbag power supply connector

WARNING:
^ Airbag power supply connector must always be disconnected before working on the airbag or related systems.
^ Connector remains connected when using VAG 1551 scan tool.

5. Passenger side airbag unit
6. Ground (GND) connection
7. Airbag Malfunction Indicator Lamp (MIL)
^ Refer to appropriate wiring diagram for location
8. Data Link Connector (DLC)
^ Located above electronic box