24/7 Semi Truck Repair & Diagnostics
Mobile Semi Truck Computer Diagnostics & Derate Repair
Emissions-related derates are one of the biggest causes of breakdowns across every engine make. A single failed NOx sensor or a DPF that can't finish a regen can drop a truck into limp mode and leave a driver stranded.
100+
Yrs Combined Experience
24/7/365
Dispatch
99%
Back on the Road Without a Tow
100 mi
Radius per Location
We Bring the Shop to Your Semi
Our technicians connect a diagnostic computer, read the fault codes and then test the related sensors, wiring and components — DEF, DPF, SCR, EGR, fuel system and turbo — to find the root cause. We repair it, clear the codes when appropriate and verify the derate is gone before we leave.
Diagnostics included: We don't just clear codes and hope. Clearing a code without fixing the cause brings the derate right back — usually at the worst time.
Semi Truck Diagnostic & Aftertreatment Services
Using Cummins INSITE, Detroit DiagnosticLink, PACCAR ESA, JPRO, Bendix, Volvo and International diagnostic software:
Derate & Limp Mode Repair
We find and repair the fault behind the derate, then confirm full power is restored.
Forced (Parked) DPF Regens
When the filter is loaded with soot but healthy, a parked regen burns it off. If it's ash-loaded or damaged, we tell you when cleaning or replacement is needed.
DEF, SCR & EGR Repair
DEF dosing and quality problems, SCR faults, EGR failures and coolant leaks into the system.
Sensor & Wiring Faults
NOx sensors, temperature and pressure sensors and the wiring that connects them.
Check Engine Lights
Active and inactive fault codes read and explained in plain language.
Same-Visit Repair
Once we find the problem, we fix it on the spot whenever possible.
Stop Guessing. Start Repairing.
Skip the Tow
No need to tow a truck to a shop just to find out what a fault code means.
Root-Cause Repairs
Fewer repeat derates and fewer unnecessary parts.
Every Major Engine
Cummins, Detroit, PACCAR MX-11/MX-13, Volvo, Mack and International.
Customer Reviews
What Drivers & Fleets Say
“We use Rapid Truck Repair regularly for road calls, and I honestly don't know what we'd do without them sometimes. They've saved us more headaches than I can count and have proven time and time again that they're people we can count on. They do great work, they're honest, and they genuinely care about taking care of their customers. A huge shoutout to Macie! She's always incredibly helpful, easy to communicate with, and willing to go the extra mile.”
“I've been in the trucking industry for many years, and this is by far the best truck service I've ever received. They were quick to respond and handled everything efficiently. On top of that, their pricing was extremely reasonable which is a huge relief when you're in a bind. I'm definitely sticking with them for any future truck service needs. Highly recommend!”
“I've had Rapid Truck Repair help me out a couple of times during the night with our semi-trucks, and they've always been on time. We broke down in Weed, CA and they went out of their way next day to make sure we had the right parts to get our truck fixed, which was super important for keeping our deliveries on schedule. Really appreciate their quick and reliable service.”
“My EGR pipe completely cracked off on my T680 with an X15 engine. I was in Yreka, California, and it was the weekend. They came out, removed my parts, went to the Kenworth dealer, picked up all the original hoses and clamps, completed the repairs, and got me home. Can't thank them enough!”
Semi Truck Diagnostics Service Areas
Available 24/7 from our service hubs and the communities around them:
FAQ
Semi Truck Diagnostics FAQs
My truck is derated or in limp mode — what should I do?
Pull over safely if needed and don't keep driving with serious warnings. Call dispatch 24/7 — our technician will read the fault codes, find the cause and make the repair.
Can you do a forced regen on the side of the road?
Yes, when it's appropriate and safe. We check first why the DPF is clogging — failed sensors, excess soot or another engine issue — so the problem doesn't come back.
Why does my DPF keep clogging?
Common causes include excessive idling, frequent short trips, interrupted regens, bad or contaminated DEF, failed sensors and underlying engine problems. A regen burns soot but doesn't remove ash, so an ash-loaded DPF needs cleaning.
What diagnostic software do you use?
Cummins INSITE, Detroit DiagnosticLink, PACCAR ESA, JPRO, Bendix, Volvo and International diagnostic systems, among others.
More Semi Truck Services
Mobile Semi Truck Repair
Roadside and on-site semi truck and trailer repair with full diagnostics — we bring the repair to your rig, day or night.
Learn moreTire Repair & Rim Replacement
Blowouts, flats and damaged rims replaced — steer, drive and trailer positions, roadside or at your yard.
Learn moreOnsite & Fleet Repair
We come to your yard or terminal to repair, maintain and inspect multiple trucks — with negotiated fleet rates.
Learn moreHeavy Duty Semi Truck Repair
Engine, brake, cooling, electrical and suspension repairs plus preventive maintenance for Class 8 trucks and trailers.
Learn moreDOT & BIT Inspections
Annual DOT inspections at every location and California 90-day BIT inspections — at your yard, with sticker and report.
Learn moreSmog & CARB Testing (CA)
California only: Clean Truck Check smog testing plus emissions diagnostics and repair to keep your registration clear.
Learn moreDerated or Dash Lit Up? Call Now
We'll plug in, find the fault and get you back to full power.