General Information

Airbag System, On Board Diagnostic (OBD)

Function

The airbag control unit -J234- is located behind the console on the tunnel. It is equipped with a DTC memory. The On Board Diagnostic (OBD) connection is located under the driver's knee bar to left of the steering wheel.

The control unit detects malfunctions in the airbag system and stores them in a permanent memory.

Malfunctions which can be attributed to a temporary open circuit in the wiring or a loose contact, will also be stored. These malfunctions will be displayed as sporadic DTCs "SP".

After the ignition is switched on, the airbag warning lamp -K75- comes on for about 4 seconds and then goes out again. If the lamp then flashes for a further 15 seconds this signals that the airbags or the belt tensioners are electronically blocked.

- If the warning lamp -K75- does not go out again after about 4 seconds, then the voltage supply to the airbag control unit -J234- is malfunctioning. Check DTC memory.
- A fault is present if the warning lamp -K75- lights up again. Check DTC memory.
- If the warning lamp -K75- flashes continuously then the control unit -J234- must be replaced.

To commence troubleshooting, initiate self-diagnosis and retrieve the stored information with the scan tool VAG 1551.

The fault information displayed is used to refer to a DTC table with notes on the possible causes for directed repair measures.


WARNING!
- Only visual check of wiring!
- Do not carry out electrical continuity tests or measurements to igniter circuits!
- Only check wiring with ignition switched off!


Introducing On Board Diagnostic (OBD) for airbag

- Connecting scan tool.
- Switch on printer with Print button (warning lamp in button lights up).
- Switch on ignition.

Indicated on display;


Rapid data transfer HELP
Enter address word XX


- Press keys -1- and -5- (the address word of the vehicle system to be tested "Airbag" is entered with 15).

Indicated on display;


Rapid data transfer Q
15 Airbag


- Confirm entry with the -Q- button.

Indicated on display;


Rapid data transfer HELP
Select function XX


NOTE:
- If one of the fault messages opposite appears in the display, the possible causes of the fault can be printed out with the HELP key.


Rapid data transfer HELP
Control unit does not answer!


- Ignition must be switched on.


Rapid data transfer HELP
K wire not switching to B+!


- Malfunctions have occurred at the start of or during the program (external interference?).


Rapid data transfer ->
No signal from control unit!


- Check diagnosis wires as well as voltage supply and Ground connection.


Rapid data transfer ->
Fault in communication build up


- After rectifying the possible causes of the fault, once again enter the address word 15 for "Airbag" and confirm with the -Q- button.

Indicated in display after entering the address word 15:


Rapid data transfer
Tester sends the address word 15


and then the following appears in the display;

Indicated on display


1J0 909 608 D AIRBAG VW 3-S V03 ->
Coding 00068 WSC 12345


- Press -> button.

Indicated on display:


Rapid data transfer HELP
Select function XX