1985 Autocar: we work on any truck
If it runs diesel and needs help, we'll show up. Age is not a barrier: classic, vintage, or modern.
Mobile Fleet Repair & Preventive Maintenance
Fleet Repair & Maintenance in Charleston, SC. Done On-Site.
Lowcountry Diagnostics keeps your trucks running with on-site fleet repair and scheduled preventive maintenance at your yard, terminal, or lot. We diagnose and fix down units, service trucks where they park, catch wear before it becomes a breakdown, and give you a written record for every truck, so downtime stays low and the fleet stays on the road.
- On-site fleet repair and scheduled PM for trucks, vans, trailers, and equipment
- Fluids, filters, brakes, tires, batteries, and fault scans in one visit
- Charleston, North Charleston, Summerville, Goose Creek, Mount Pleasant
What We Service On-Site
One mobile tech for your whole PM program
Engine & fluids
Oil and filter changes, coolant, fuel filters, and DEF checks on the interval that fits your mileage and duty cycle.
Brakes & air system
Air brake inspection, slack adjusters, chambers, lines, and air leaks checked and adjusted where the truck sits.
Tires, wheel ends & chassis
Tire condition, tread, wheel ends, suspension, and steering looked over to catch problems before a roadside failure.
Electrical & fault scan
Batteries, charging, lights, and a scan for stored codes so aftertreatment and engine faults are caught early.
Fleet Repair On-Site
Fleet repair when a unit goes down
PM keeps most problems from happening, but trucks still break. When a unit throws a derate, won't start, or loses air, we come to the yard or the roadside, test the system, and repair it on-site where we can, so you are not waiting on a tow and a shop queue.
Derates & aftertreatment
Limp mode, failed regens, and DEF, SCR, and NOx faults traced to the cause. See diesel derate repair and DPF and DEF diagnostics.
Brakes & air leaks
Chambers, slack adjusters, valves, dryers, and air lines repaired so the unit is safe and back in service. See air brake repair.
Electrical & no-starts
Batteries, charging, starters, wiring, and sensor faults tested before parts are replaced. See electrical diagnostics.
Roadside breakdowns
A driver stuck on I-26 or US-52 gets a tech at the truck, 24/7. See 24 hour roadside truck repair.
Why On-Site PM
Maintenance that fits around your routes
Every hour a truck spends in a shop line is an hour it is not earning. On-site preventive maintenance changes that. We come to your location and service units while they are idle (before a shift, between routes, or overnight) so the truck is ready when your driver is.
Consistent PM also means fewer surprises. Catching a worn brake, a weak battery, or an early fault code on a scheduled visit is far cheaper than a tow and a missed delivery. You get a written record for each unit and a clear picture of what needs attention next.
Why operators call us
- Mobile service where the truck is sitting
- Testing before parts replacement
- Clear written findings and next steps
- Commercial diesel and fleet-focused support
- 24/7 Charleston-area availability
How Fleet PM Works
What a maintenance program looks like
1. Tell us your fleet
Number of units, makes, engines, and how hard they run tells us the right intervals and service scope.
2. Set a schedule
We build PM intervals around your mileage and routes so units get serviced while they are parked and idle.
3. We come to you
Yard, terminal, or lot across the Charleston area. No need to shuttle trucks to a shop for routine service.
4. Full PM inspection
Fluids, filters, brakes, tires, batteries, lights, and a fault-code scan handled in one on-site visit per unit.
5. Written record per unit
Each truck gets documented findings and recommendations that support DOT compliance and planning.
6. Head off breakdowns
We flag wear before it strands a truck, so you replace parts on your schedule instead of on the roadside.
Sample PM Checklist
What a typical on-site PM visit covers
Intervals are set per unit around mileage, routes, and duty cycle. On each scheduled visit, the truck gets checked where it is parked:
- Oil and filter change
- Coolant, fuel filters, and fluid levels
- DEF check
- Air brake inspection and adjustment
- Slack adjusters, chambers, and air lines
- Air leaks
- Tire condition and tread
- Wheel ends, suspension, and steering
- Batteries and charging
- Belts and hoses
- Lights
- Scan for stored fault codes
What fleet managers get
- PM intervals built around your mileage and routes
- Service at your yard, terminal, or lot while units are idle
- A written service record for each unit, with findings and recommendations
- Wear flagged early, so parts get replaced on your schedule
- On-site repair when a unit goes down between visits
Ready to cut fleet downtime in Charleston?
Call or text Lowcountry Diagnostics to set up on-site preventive maintenance.
Common fleet repair and maintenance questions
Do you handle fleet repairs, or only PM?
Both. We repair fleet trucks on-site when they go down, including derates, aftertreatment faults, air brake problems, electrical and no-start issues, and roadside breakdowns, and we run scheduled PM to prevent them.
Do you perform fleet PM on-site?
Yes. We come to your yard, terminal, or lot and perform scheduled preventive maintenance where your trucks park, so units stay in service instead of sitting in a shop queue.
Can you service trucks after hours or on weekends?
Yes. We schedule PM around your routes, including nights and weekends, so maintenance happens while trucks are idle and available across the Charleston area.
What is included in a preventive maintenance service?
Typical PM covers oil and filters, fluid levels, brakes and air system, tires and wheel ends, batteries and charging, belts and hoses, lights, and a scan for stored fault codes with a written report.
Do you keep maintenance records for our fleet?
Yes. Each unit gets a written service record with findings and recommendations, which helps with DOT compliance and planning the next interval. Call or text (843) 310-0995.
Request a Fleet Maintenance Quote
Tell us about your fleet and where the trucks park. We will follow up to set up on-site PM. For urgent needs, calling or texting is fastest.
Truck down right now? Call or text (843) 310-0995.
Recent Repair Photos
A look at the repairs we make
Real field photos from Lowcountry Diagnostics, from engine diagnostics and electrical to hydraulic, HVAC, and heavy-duty truck service, handled on-site across the Charleston area.
Reviews
What Charleston truck owners and fleets say
“Joseph and team are top-notch! One of my fleet trucks went down and within the hour they had us back up and operational.”
“Very reliable.. very transparent.. good service .. I would highly recommend and will be calling him again”