Mobile Fleet Diagnostics in Tulsa
Scan-tool code reads, electrical and data-bus testing, and DPF, DEF and SCR diagnosis, done on site at your yard or jobsite anywhere within 120 miles of Tulsa. Find the cause first, then fix only what is broken.
Diagnosis Before Parts
Most expensive breakdowns start as a vague complaint and end with parts being swapped until the light goes out. A diagnostic visit works the other way around: read the codes, watch the live data, test the circuit or system the code points to, and name the cause before anything is replaced. Our technicians, led by Gary Dale, Master Diesel Technician, do that work on site, where the problem is happening.
It is the first step of nearly every repair on this site, and it is also a service on its own: a unit that runs but throws codes, a fleet truck with an intermittent fault, or a pre-purchase look at a used truck or piece of equipment.
What a Diagnostic Visit Covers
Code Reads and Live Data
A scan tool over the truck's data link (OBD-II, J1939 and J1708) reads active and stored fault codes and watches live data while the fault happens. A code is where diagnosis starts: the SPN and FMI say which circuit or system to test, not which part to buy.
Diesel repair guideElectrical, Wiring and Data Bus
Voltage drop tests on battery cables and grounds, harness and connector checks, CAN bus resistance and voltage readings, and parasitic draw tests for batteries that go dead overnight. Intermittent faults are found where they happen, with the harness wiggled while the readings are watched.
Cascadia electrical diagnosticsDPF, DEF and SCR Aftertreatment
Soot-load and regen status, forced regens, DEF quality testing, dosing and NOx sensor checks, and derate countdowns read off the scan tool. A forced regen burns off soot but not ash, so the test also tells you whether the filter itself is the problem.
DPF maintenance and regensStarting, Charging and Batteries
No-start and no-crank complaints, battery and cable testing, and alternator and starter checks. Most of it is settled on the shoulder or in your lot faster than a tow truck can arrive.
Alternator and starter repairWhen to Call
- Check-engine, amber or red stop lamp that won't stay off
- Derate, reduced power or a 5 mph limit
- DEF warnings or an exhaust fluid quality fault
- Regen that won't complete or keeps coming back
- Intermittent stalling or a no-start that comes and goes
- Dash gauges or lights dead or acting up
- A battery that goes flat overnight
- A/C that's weak or cycling, found with gauge readings
How a Visit Works
Call or send the symptoms
Tell us the unit, what it is doing and any fault codes or lamps you already have. Photos of the dash help.
We come to the unit
Your yard, jobsite or the roadside, anywhere within 120 miles of Tulsa. Emergency response is available 24/7.
Test, don't guess
Codes and live data first, then the meter, the bus and the circuit the code points to, until the cause is proven.
Fix it or plan it
Most diagnosed faults are repaired on the spot. If a job truly needs a bay, you hear that before the unit moves.
Diagnostics on Real Jobs
More in the photo gallery.
Trucks and Equipment We Diagnose
Diesel trucks, vans and pickups and the equipment that works beside them, including semi trucks, delivery fleets, excavators and farm equipment. Brand pages with more detail:
Related Services
- DOT inspections — the annual inspection under 49 CFR 396.17, at your yard.
- Preventive maintenance — catch the fault before the derate.
- Emergency repair — when a unit is already down.
- Equipment appraisals — a condition report before you buy or sell.
- Diesel emissions compliance — how derates and inducement timers work.