It doesn't need to be a Cummins shop, any big truck dealer repair shop will have the equipment to check it out. Look up Freightliner or any other truck dealer along your route and call to make an appointment because most truck shops are usually booked up 4,5, or even a week......trust me I spent 0ver 35 years on the road driving a semi coast to coast and border to border. Nashville has all the repair shops you could ever need... Freightliner, Kenworth, Peterbilt and plenty of authorized Cummins shops. If you hire a service truck to come to you you will pay dearly for it and he probably won't have the diagnostic/computer equipment like a full service shop will.