We investigate a class of dark energy models in which the equation of state undergoes a rapid transition and for which the Hubble SN Ia diagram is known to be poorly discriminant .
Interestingly enough , we find that transitions at high redshift can lead to distortion in the correlation function of dark matter at lower redshift .
We therefore use a combination of the SN Ia Hubble diagram , Cosmic Microwave Background data and power spectrum from the Sloan Digital Sky Survey Luminous Red Galaxies ( SDSS LRG ) to constrain the redshift of a possible transition .
We find that the fundamental cosmological parameters are well constrained independently of the presence of a transition .
Acceptable transitions from an equation of state close to w = 0 to a value close to -1 are strongly rejected at redshifts much higher than those for which Large Scale Structure and SN Ia data are available : the transition redshift can be rejected up to a value as high as 10 .
We conclude that no preference for a transition appears from present-day data .