To perform load changes in proton exchange membrane (PEM) fuel cells is a challenging task, because PEM fuel cells typically show a strongly nonlinear behavior. Especially the water management of low temperature PEM fuel cells is challenging. In this work, a nonlinear controller is presented that is able to keep the water content and the temperature of a PEM fuel cell on constant levels even under strong changes of the electrical load. A passive controller design based on a spatially distributed fuel cell model is used. The controller is tested in simulations. It is compared with a conventional linear control approach.