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Mobile Diesel USA
Services
Phoenix dispatch, 7 AM to 7 PM Arizona time

Engine diagnostics and repair

Advanced computer diagnostics and hands-on engine repair for all diesel makes — dispatched to your location. No shop visit required.

Get help nowCall (602) 456-9071

How it works

Describe the symptomsTell us what your engine is doing — codes, warning lights, performance issues, noises, or smoke. Include your truck make/model/year.
Mechanic dispatchedWe send a diesel engine specialist to your location with the right tools and common parts for your platform.
Diagnose and quoteYour mechanic runs a full diagnostic, identifies the root cause, and provides a repair quote before starting work.
Repair completeRepair is performed on-site, codes cleared, and systems verified. You're back to full power with documentation of what was done.

Find the problem. Fix it where you stand.

Modern diesel engines throw codes, derate, and shut down for dozens of reasons. A mechanic with diesel scan tools finds the cause before anyone quotes. From a simple sensor swap to a major engine repair, we handle it on-site.

  • Fault code diagnosis

    Full ECM scan, fault code interpretation, freeze frame data analysis, and root cause identification for check engine lights and derate conditions.

  • Turbocharger repair

    Turbo boost leak testing, wastegate adjustment, VGT actuator repair, and turbo replacement for all major diesel platforms.

  • Injector service

    Injector testing, replacement, and calibration. Contribution balance testing and cylinder cutout diagnosis for rough-running engines.

  • Head gasket and top end

    Coolant-in-oil diagnosis, head gasket replacement, valve adjustment, and cylinder head repair performed on-site when possible.

  • EGR and emissions systems

    EGR valve cleaning and replacement, EGR cooler service, and emissions system diagnostics for derate and limp mode conditions.

  • Oil and fluid analysis

    Oil pressure diagnosis, oil leak repair, coolant system pressure testing, and fluid analysis to catch problems before they become failures.

Questions

No estimates. The mechanic diagnoses, quotes, and you approve before any work.

Our mechanics service all major diesel engine platforms including Cummins, Detroit Diesel, CAT, PACCAR (MX-11, MX-13), Navistar/International, and Volvo/Mack. We cover Class 6 through Class 8 commercial vehicles.

Yes. Mechanics use diesel scan tools that read OEM-level fault codes, perform forced regens, and access proprietary parameters needed to diagnose and clear derate conditions.

Mechanics often carry common parts like sensors, belts, hoses, filters and gaskets. For major components like injectors or turbos, the mechanic sources the part from a local supplier and returns to finish the job. The parts go on the quote you approve.

If a repair requires shop equipment (like a machine shop for cylinder head work), your mechanic will diagnose the issue, explain what's needed, and help coordinate next steps. Many repairs that seem shop-level can actually be completed in the field.

In the app or on your secure status page, by card, after you approve the price. Nobody should ask you for cash at the truck.

The Phoenix, Arizona metro, 7 AM to 7 PM Arizona time, every day. Chicago and Detroit are launching next and are not available yet. If anyone is in danger, call 911.

Need this fixed in Phoenix?

Tell dispatch where the truck is and what it's doing. If anyone is in danger, call 911.

Get help nowCall (602) 456-9071