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Home >> BMW >> 2012 >> 740i >> Repair and Diagnosis >> Steering >> Power Steering >> Chassis Dynamics -- Overview - F01/F02 >> F01 Vertical Dynamics Systems >> Electronic Ride-height Control >> Function of Air Springs >> Pre-mode

Function of Air Springs: Pre-mode

Pre-mode is activated by the "Load cutout OFF" signal (e. g. in response to opening of the door or unlocking with the radio remote control). The Pre-mode then stays set for 16 minutes and is restarted with a change in status.

The ride height of the vehicle is monitored and evaluated with a wide tolerance band.

In Pre-mode, the vehicle is only controlled up to the nominal height if the level is significantly below the nominal height. This control tolerance ensures that the vehicle is only controlled up in the case of large loads in order to increase the ground clearance prior to departure. Small loads give rise to small compression travel and this is compensated only when the engine is started. This control setting helps to reduce the battery load.

PRE MODE CODING PARAMETERS

Coding parameter Value
niv_pre_up_e - 09 mm
niv_pre_up_d - 07 mm
niv_pre_down_e + 09 mm
niv_pre_down_d + 07 mm
niv_pre_mw_up - 59 mm(1)
niv_pre_mw_down 0 mm
pre_delay_counter 20 min
(1) Average figure

With single-axle air suspension, the vehicle is controlled down when the mean value of both ride height signals is > 0 mm and one side is in excess of + 10 mm.

In this mode, only the mean value of the two ride height signals (fast filter) is considered when deciding whether there is a need for a control operation.

There is no inclination detection in Pre-mode.