Not sure, I am inquiring and will follow up.

GrabTaxi has launched services in Pattaya, but that service appears to be for local services. But it wouldn't surprise me if there was some linkage with Bankok, and thus services between the two cities. One issue is that with GrabTaxi you typically use the meter, while most taxis will negotiate a flat-rate to Pattaya (~ 1,000 - 1,500 THB, one-way + you pay any tolls), and long-distance fares to locations outside Bangkok do go by a published, official DLT chart - but I don't see Pattaya/Chonburi on those charts. By the meter, the fare might be ~ 1,150 +/- 150 THB, I think.

I assume GrabCar is under the same "thainess" scrutiny as Uber?