Blazars being the beamed population of AGN, are the most copious and variable constant emitters of radiation in the Universe. The detailed processes that give rise to those characteristics though, are still under intense debate. In August 2008, Fermi/LAT discovered the distant blazar PKS 1502+106 (z=1.839) showing a rapid and strong gamma-ray outburst followed by bright and variable flux over the next months. This activity at high energies triggered an intensive multi-wavelength campaign indicating that the outburst was accompanied by a significantly delayed counterpart at radio bands. Utilizing ultra-high angular resolution VLBI imaging at 15, 43, and 86 GHz, we attempt to shed light on the physics of the jet flow right after this high-energy flare. Furthermore, we aim at localizing the gamma-ray emitting region. In this talk the findings of the mm-VLBI study using the Global Millimeter VLBI Array (GMVA) data between 2009 and 2012, will be presented. These imply an accelerating jet. The viewing angle towards the source differs between the inner and outer jet, with the former at ~3 degrees and the latter at ~1 degree, beyond the first milliarcsecond. A single component travelling within the bent jet of PKS 1502+106 can be associated with the pronounced flare both at high-energies and in radio bands.