Description of On Board Diagnostics

CAUTION!
Use ONLY the VAG1551 Scan Tool (ST) and appropriate adapter to test the "Airbag II, Airbag III and Airbag V" systems. Do not use the VAG1619 airbag tester.


The Airbag II, Airbag III and Airbag V systems are equipped with On Board Diagnostic (OBD) capability. If there is a malfunction in a monitored sensor or other component, a Diagnostic Trouble Code (DTC) is stored in DTC memory.

If a malfunction is recognized, the airbag Malfunction Indicator Lamp (MIL) in the instrument cluster will be illuminated. The airbag MIL remains on until DTC memory is checked and then erased using the VAG1551 scan tool, even if the malfunction no longer exists (sporadic).

If the airbag or airbags have been deployed, DTC memory records whether they were deployed correctly (crash data). DTC memory also records whether any malfunctions had been recognized and stored as DTCs at the time of deployment.

The airbag control module can distinguish between different types of malfunctions, which are recorded as DTCs in DTC memory. The DTCs remain stored until DTC memory is checked and then erased using the VAG1551 scan tool.

The full range of OBD functions can only be fully utilized using the VAG1551 scan tool.


NOTE: CRASH DATA CANNOT BE ERASED.


VAG1551 scan tool operating modes:
1 - Rapid data transfer
2 - Blink code output
3 - Self test
4 - Dealership code

"Rapid data transfer" operating mode 1 permits checking DTC memory and testing some components in output Diagnostic Test Mode (DTM) using the VAG1551 scan tool.

"Blink code output" operating mode 2 cannot be used.

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


WARNING!
When driving or riding in an airbag-equipped vehicle, never hold test equipment in your hands or lap while the vehicle is in motion. Objects between you and the airbag can increase the risk of injury in an accident