DOT Inspections
    90-Day BIT Inspections
    CARB Clean Truck Check Support
    Diesel Diagnostics
    Fleet Maintenance
    Engine Repair
    EGR & DPF Repair
    Mobile Truck Repair
    Roadside Assistance
    DOT Inspections
    90-Day BIT Inspections
    CARB Clean Truck Check Support
    Diesel Diagnostics
    Fleet Maintenance
    Engine Repair
    EGR & DPF Repair
    Mobile Truck Repair
    Roadside Assistance
    Heavy duty diesel pickup truck inside the Rapid Diesel Repair shop in Ontario, CA
    RAPID DIESEL REPAIR

    Diesel Truck Repair in Ontario, CA

    Diesel truck issues?Let’s get it diagnosed today.

    From one diesel truck to an entire fleet, get ASE certified expert diagnostics, solid repairs, and fast turnarounds. We're local and service light, medium, and heavy-duty trucks.

    Google
    300+ 5 Star Reviews

    ASE Certified Technicians
    Dealer Level Repairs

    “10/10 experience!! Got an oil change and new air filter on a company truck checked in and out less then a day.”
    Michael C. · Verified Google Review

    REQUEST DIESEL SERVICEONTARIO, CA

    Tell us about your truck and what it is doing and we will get back to you to confirm your appointment.

    Call (909) 701-8755 to Schedule

    FAST & CONVENIENT LOCAL DIESEL SERVICE

    Describe the Issue

    ABOUT
    RAPID DIESEL REPAIR

    Rapid Diesel Repair is a premium diesel truck and fleet repair shop in Ontario, CA. Our ASE certified technicians use dealer level diagnostics to service light, medium, and heavy duty diesel vehicles, from work pickups to class 8 tractors. We handle engine and drivetrain repair, advanced diagnostics, emissions system repair, preventive fleet maintenance, and DOT, BIT, and CARB compliance support. Owner operators and fleet managers rely on us for accurate diagnosis, clear communication, and repairs that reduce downtime.

    Why Fleets Choose Rapid Diesel Repair

    • • ASE certified diesel technicians
    • • Dealer level diagnostic capability
    • • Light, medium, and heavy duty service
    • • Fleet maintenance programs
    • • DOT, BIT, and CARB compliance support
    • • Clear communication and reduced downtime

    ASE Certified Technicians

    Trained diesel technicians who diagnose accurately and repair to manufacturer specification.

    Dealer Level Diagnostics

    Manufacturer level scan tools and live data testing to find the real fault, not a guess.

    Light to Heavy Duty

    Diesel pickups, work trucks, box trucks, and class 8 tractors serviced under one roof.

    Compliance Support

    DOT inspections, 90-day BIT inspections, and CARB Clean Truck Check repair support.

    OUR SERVICES

    Diesel diagnostics, engine and drivetrain repair, emissions compliance support, fleet maintenance, and mobile service for trucks in Ontario, CA and the Inland Empire.

    DOT Inspections

    Federal DOT inspection service for commercial trucks and trailers, with repairs handled in house.

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    90-Day BIT Inspections

    Periodic BIT inspection service for California fleets, with clear documentation of findings.

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    CARB Clean Truck Check / Emissions Compliance Support

    Emissions compliance support, pre-test diagnostics, and repair for diesel vehicles subject to Clean Truck Check.

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    General Diesel Repair

    Complete repair service for light, medium, and heavy duty diesel trucks and equipment.

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    Advanced Diagnostics & Electrical Repair

    Dealer level diagnostics for engine faults, sensors, wiring, and hard to trace electrical problems.

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    Engine Repair, Rebuild, Overhaul & Conversion

    In frame and out of frame engine work, rebuilds, overhauls, and diesel engine conversions.

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    EGR, DPF & Aftertreatment Repair

    Repair and cleaning service for EGR, DPF, DEF, and SCR aftertreatment systems.

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    Transmission, Clutch & Drivetrain Repair

    Transmission service, clutch replacement, driveline and differential repair for trucks and fleets.

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    Suspension, Steering & Truck Alignment

    Suspension repair, steering service, and heavy duty truck alignment to protect tires and handling.

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    Brake, Air Brake & Wheel-End Repair

    Air brake and hydraulic brake service, wheel-end repair, and hub and bearing work.

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    Cooling, HVAC & Fluid Service

    Radiator and cooling system repair, truck air conditioning service, and full fluid maintenance.

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    Preventive Fleet Maintenance

    Scheduled maintenance programs built to reduce downtime and extend the life of your fleet.

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    Mobile Truck Repair, Roadside Assistance & Towing

    Mobile diesel repair, roadside assistance, and towing support when a unit cannot make it to the shop.

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    Performance Upgrades

    Performance and durability upgrades for diesel trucks that stay within legal requirements.

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    RV, Trailer & Specialty Diesel Service

    Diesel service for motorhomes, trailers, and specialty equipment including chassis and brake work.

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    Manufacturer Expertise

    Experience across the major diesel truck, engine, and drivetrain manufacturers on the road today.

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    PREMIUM DIESEL TRUCK & FLEET SERVICE

    ASE Certified Technicians
    Dealer Level Diagnostics
    Light To Heavy Duty
    DOT & BIT Inspections
    Fleet Maintenance
    Ontario, CA Shop

    TRUSTED BY 300+ 5 STAR CUSTOMERS

    Real repair work. Clear communication. Trucks back on the road.

    300+ 5 Star Reviews

    Rapid Diesel Repair | Ontario, California

    After having a mobile diesel company come to my house which ended with 2 techs come out and charge me for over an hour of basically guessing what the problem was. I got a flyer from a diesel repair shop Rapid Diesel repair in Rancho Cucamonga towed my truck there they found one of the issues where my truck wouldn't communicate with a scanner which was caused by the techs that came to the house broken ground wire from the battery to the ECM from there Rapid diesel was able to find injector in cylinder #5 was bad and needed to be replaced . They recommend to replace all 6 injectors and at 231,296 miles and definitely agreed and here it is Friday and im picking my truck up . The guys here at Rapid Diesel Repair are very friendly professional and the first thing they did when I got there was give a great welcome got a tour of the shop ( I've never seen a shop this clean and organized with quite a few trucks being diagnosed worked on etc. These gentlemen told what was going to happen and thats exactly what they did so a BIG THANK YOU to Rapid Diesel Repair for a quality and professional costumer experience and a scale of 1to 10 I'd give them and 11 !!!!!!!

    READ FULL REVIEW

    Sean W.

    Verified Google Review

    I've brought my trucks to Rapid Diesel Shop a couple of times now and have had a great experience each time. Robert is great, very knowledgeable, honest, and always willing to help and answer any questions we have. They've replaced both a radiator and a driveshaft for us, and we haven't had any issues with the work. One thing I really appreciate is their communication. They kept in constant contact with us throughout the repairs and provided updates along the way, so we always knew what was going on with the truck. Their service has been fast, reliable, and professional, which is especially important when you depend on your trucks for work and need to get them back on the road as quickly as possible. Definitely recommend Rapid Diesel Shop if you're looking for knowledgeable mechanics, good communication, and quality work. We'll continue bringing our trucks here whenever we need repairs!

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    HNE Transport

    Verified Google Review

    It's hard to find a good, reliable, diesel mechanic. Now that I found Rapid Diesel Repair my search is over. The entire team from the receptionist to the guy's working on my truck in the back were extremely professional. I have a 2010 Ram 3500 that my entire business revolves around. It was had a long list of repeat need to be made. Rapid Diesel fixed everything with full upfront cost disclosure. If there was any repairs I did not want to make, the still gave me the diagnostic so I would know what I have to fix later. Thanks Rapid Diesel for keeping my rig on the trail!

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    Desi H.

    Verified Google Review

    I have a motorhome with a Freightliner chassis ; and I made the best choice when I selected Rapid Diesel! Great to work with and very friendly. And they don't hold it against you that you only have a motorhome!

    Bill H.

    Verified Google Review

    Upfront, great communication, great pricing! Had to get my truck towed here as an emergency and everything was handled as such. Financing available too!

    Steve S.

    Verified Google Review

    Amazing! They did great work on my truck! After being told by several other shops that they couldn't help me, this place did the job!!

    Samantha L.

    Verified Google Review

    Trust your truck to a shop that communicates clearly, diagnoses correctly, and gets you back to work.

    FAQ

    CONTACT OUR SHOP

    Shop Address

    251 Kettering Dr., Ontario, CA 91761

    Serving Ontario and the Inland Empire

    Hours

    Mon to Fri: 8:00 AM to 4:00 PM
    Sat and Sun: By appointment
    Towing: 7:00 AM to 9:00 PM

    DIESEL & FLEET TIPS

    Electrical and Diagnostics

    7 Common Mistakes in Electrical Repairs for Kenworth W990 Trucks

    W990 warning lights, no starts, or intermittent electrical faults? Learn seven repair mistakes to avoid and when to book diesel diagnostics in Ontario, CA.

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    Suspension and Steering

    6 Signs Your Truck’s Suspension Needs Immediate Repair

    Truck leaning, bouncing, pulling, or wearing tires unevenly? Learn six suspension warning signs and schedule a heavy duty inspection in Ontario, CA.

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    Fleet Compliance

    Your Roadmap to CARB Compliance for Heavy Duty Diesel Fleets

    Organize California Clean Truck Check deadlines, emissions repairs, testing records, and fleet maintenance. Get diesel diagnostics in Ontario, CA.

    Read More
    Suspension and Steering

    Winter Suspension Maintenance for Heavy Duty Trucks: Shocks, Springs, and Bushings

    Inspect truck shocks, leaf springs, bushings, air suspension, and mounting hardware before winter routes. Book suspension service in Ontario, CA.

    Read More