If, as planned, we're going to drive to New Jersey and back tomorrow, we need another shot of hydrogen today, so it's off to the General Motors Technical Center (rather than the White Plains refueling station), since GM's facility is the only refueling station that's open on this Saturday.
On the way, the message display says to Call Service Center Soon, so it's a good thing we're headed to GM. The GM Tech Center refueling site is "full-serv" (they pump the hydrogen for you), and after the on-site tech guy refills the car, he checks under the hood - and then plugs in his laptop under the dash. "Usually when we get this message it's because the coolant is low," he says. It's a closed-loop system, and he admits that they're not sure whether it's evaporating or what. He tops up the coolant tank under the hood and we're on our way.