Not to be confused with Ecto-4 from NOW Comics The Real Ghostbusters.
The Ecto-4WD became the primary transportation of the Ghostbusters senior team before the events of Dumazu's resurrection. It does engage in communications mostly to and from the Firehouse and can get a remote fix on the Ghostbusters. During the Dumazu incident, Ecto-4WD crashed three times, while transporting the junior team, in the streets of New York City. The first crash was into a fire hydrant while fleeing from ghosts. The second was due to an earthquake generated by the Subway Smasher. The third was another fissure caused by the Huge Spider and its Giant Spiders.
The Ecto-4WD is basically a utilitarian vehicle that the Ghostbusters ride in both the back, and on top of.
During the early proposal stage, Javier Martinez submitted a concept design that portrayed Ecto-4WD as a modified truck. 
- On page 17 of Ghostbusters Volume 2 Issue #18, there is a reference to Ecto-4WD in a side note on the middle of the chalkboard.