Note before disconnecting battery cables

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Volvo S80, 2005 Volvo S80, 2004 Volvo S80, 2003 Volvo S80, and 2002 Volvo S80. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Identifying Ignition In Off Position And Disconnecting Negative Cable From Battery

Courtesy of VOLVO CARS OF NORTH AMERICA.

WARNING: The SRS (supplemental restraint system) is active for a certain time after the power is cut. Therefore wait three minutes before starting work.

If the malfunction indicator light in the combined instrument panel is illuminated, the diagnostic trouble codes for the management system must first be read out and remedied before battery power is cut off.
The ignition should be off for at least five minutes before the battery is disconnected from the car to allow the control modules time to store information.
If the vehicle is equipped with remote heating, the personal code is reset to the factory value (1234) if the battery is disconnected or is discharged.

CAUTION: Always disconnect the negative battery cable before disconnecting any positive cables.