Semi Truck Diagnostics & Diesel Engine Repair Near You
Check engine light · ECM diagnostics · PM & oil change · Same-day diagnosis on most trucks · OEM parts · 3 minutes off I-94
Diesel Engine Repair
From performance loss to full rebuilds, our techs work on major diesel engine platforms used across Class 6-8 trucks. We diagnose before we quote, so you know the actual cause before any work starts.
ECM / Computer Diagnostics
Modern diesel engines run through an engine control module (ECM) that logs fault codes long before a problem becomes a breakdown. We pull and interpret those codes to triage check-engine lights fast and accurately.
Common Failure Points We See
- Fuel system and injector issues
- Turbocharger and boost-related faults
- After-treatment system faults (DPF, SCR, EGR)
- Sensor failures triggering false or misleading codes
- Cooling system leaks and overheating
PM Service & Semi Truck Oil Change
Many engine problems start with skipped maintenance. We also do semi truck oil changes and preventive maintenance (PM): engine oil and filter, fluid checks and top-offs, and a multi-point inspection of belts, hoses and leaks, so small problems get caught before they turn into a breakdown. See PM service & oil change or call (224) 588-3442.
If your fault ties into a broader after-treatment or electrical issue, see also our Semi Truck Repair Truck Brands page.
Built for Drivers Who Can't Afford Downtime
Fault codes get interpreted, not just cleared — you get the real cause.
Techs experienced across the diesel engines common to Class 6-8 trucks.
Fast turnaround on figuring out if it's urgent or can wait.
Diagnostics and repair happen in the same bay — no handoff delay.
Diagnostics & Electrical
Computer diagnostics, electrical, cooling and A/C work in our shop.
4.9★ from 360+ Google Reviews
“I’ve been to a lot of shops, and RT Group is one of the few that actually does what they say. Rolled in with an issue on my trailer — no lights, busted wire. They got me in quick, showed me exactly what was wrong, and had it fixed that same day.”
“Brought my Freightliner Cascadia to RT Group after an air leak and brake issues. The mechanics found the problem quickly, explained what needed to be repaired, and got the truck back on the road the same day. No guessing, no unnecessary work, no surprise charges.”
“Great people working. Very professional and do quality work. We came in for some electrical issues on the trailer after another road service made a big mess there. They found the problem and fixed it quickly. Highly recommend this place.”
Common Questions
My check engine light is on — is it safe to keep driving?
Can you clear a fault code without a real repair?
Do you work on all major diesel engine brands?
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Ready When You Are
Call now to talk to a live person, or request a quote and we'll follow up fast.