Precautions for Removing Battery Terminal: Notes

When removing the 12V battery terminal, turn OFF the power switch and wait at least 5 minutes.
NOTE: ECU may be active for several minutes after the power switch is turned OFF. If the battery terminal is removed before ECU stops, then a DTC detection error or ECU data corruption may occur.
Always disconnect the battery terminal within 60 minutes after turning OFF the power switch. Even when the power switch is OFF, the 12V battery automatic charge control may automatically start after a lapse of 60 minutes from power switch OFF.
Disconnect 12V battery terminal according to the following steps.

Fig 1: Disconnecting Negative Battery Terminal
Courtesy of NISSAN NORTH AMERICA, INC.