The code
\documentclass[12pt,a4paper]{article}
\usepackage[american]{circuitikz}
\begin{document}
\begin{circuitikz}
\draw (1,0) to[short, i<=2] (1.5,-2);
\end{circuitikz}
\end{document}
gives an error
! Undefined control sequence.
\tikz@anchor ->\pgf@circ@dir
If I change e.g., to
\draw (0.8,0) to[short, i<=2] (1.5,-2);
or I remove the i<=2 it compiles fine. I use a standard installation of macTeX on macOS 10.12.1.