Battery disconnection

I am working on a 14-plate Audi Quattro TT with an illuminated SRS light. The owner has had the code read by the dealer, which is ‘N200 – passenger side airbag, igniter circuit high resistance’. I plan to check the connections below the seat, so will be detaching the negative terminal from the battery. Are there any special procedures or precautions I should observe?

Frank Coyle

As you suspect, the connection to the airbag system under the seat is the most likely source of the failure. When disconnecting the battery on the TT, the advice given by Autodata is that you should open the windows slightly, turn off the ignition and then wait 10 minutes before disconnecting the battery. If you’re working on the SRS system, it is also recommended that the ignition should be switched on (battery disconnected).

If the TT has a battery condition sensor then the multi-plug connection should be disconnected before reconnecting the battery. The battery should then be reconnected with the ignition on and the windows down, after ensuring the doors are closed.

Once the battery is connected the condition sensor multi-plug should be reconnected and any codes cleared. The electric windows will then need to be reset. This is done by lifting the window switch to close the window, then, when the window is up, releasing the window switch and holding it in the ‘close’ position for another second.

If the vehicle has a compass display in the rear-view mirror, this will also need to be reset by driving the vehicle in a full circle at around 5mph. Finally, the steering angle sensor will need to be reset, which should be completed after a short drive of around 10 metres.