We present the results of a study on the prospect of detecting habitable trojan planets in the Kepler Habitable Zone circumbinary planetary systems (Kepler 16, 47, 453, 1647, 1661). We integrated the orbits of 10,000 separate 4-body systems (6-body systems in the case of Kepler 47), each with a one Earth-mass trojan planet in a randomly selected orbit near the Lagrangian points of its host planet. Stable orbits are restricted to a narrow range of semi-major axes in all five systems and limited to small eccentricities in Kepler 16, 47, and 1661. The mean amplitudes of the transit timing variations (TTVs) correlate with the mass of the transiting planet and range from 70 minutes (Kepler 16) to 390 minutes (Kepler 47). These results suggest that the detection of an Earth-mass trojan planet from TTVs is possible in systems like these. The period of oscillation of the TTVs for Kepler-16 is 20 transits (12.5 years), which suggests that the orbital characteristics of such a massive trojan planet could be inferred from a decade of transit data.