A series of molecular signals initiated by binding of a ligand to an epidermal growth factor receptor (EGFR/ERBB1) on the surface of a cell, followed by transmission of the signal by a heterodimeric complex of ERBB2 and EGFR. ERBB2, which does not bind any known ligand, is activated through formation of a heterodimer with another ligand-activated ERBB family member such as EGFR.