When your diesel truck throws a check engine light, loses power, or goes into derate mode, you need answers fast. AZ Mobile Diesel Repair provides professional engine diagnostics and computer repair at your location—whether you’re on I-10, at a job site, or in a warehouse lot.
Our ASE-certified technicians use OEM-level diagnostic tools for all major diesel engines: Cummins, Detroit, Caterpillar, International (MaxxForce), and Paccar MX. We identify the root cause of engine faults, clear codes, perform DPF regens, reprogram ECMs, and complete on-site repairs when possible—all within a 30-60 minute response window.
What’s Included in Our Engine Diagnostic Service
Computer Diagnostics & Fault Code Reading
We retrieve active and pending fault codes, freeze frame data, and live sensor readings to pinpoint the issue
ECM Reprogramming & Updates
Software updates, parameter changes, and ECM reflashing to resolve engine performance issues
Sensor Testing & Replacement
Test and replace faulty sensors: MAF, MAP, IAT, coolant temp, oil pressure, and more
Forced DPF Regeneration
Perform parked or stationary regens to clear DPF clogs and restore engine power
Wiring Diagnostics
Trace electrical faults, shorts, and open circuits in engine harnesses and connectors
Post-Repair Verification
After repairs, we test-drive (when possible) and verify all fault codes are cleared
✓ Our diagnostic process identifies the root cause—not just the symptom. We don’t throw parts at a problem; we test, confirm, and repair the right way.
What Happens When You Call
Here’s our proven 4-step engine diagnostic process:
1
Initial Assessment & Dispatch
When you call (602) 456-9071, we ask about symptoms: warning lights, power loss, unusual sounds, derate conditions. Our dispatcher sends a technician with the right diagnostic tools for your engine make/model. Average ETA: 30-60 minutes.
2
Computer Scan & Fault Code Analysis
We connect our diagnostic laptop to your ECM and pull all active/pending fault codes, freeze frame data, and live sensor readings. This reveals exactly what the engine computer sees, helping us identify the failing component or system.
3
Physical Inspection & Testing
Fault codes point us in the right direction, but we confirm the diagnosis with hands-on testing: checking sensor voltages, inspecting wiring harnesses, testing fuel pressure, verifying turbo operation, and examining exhaust components.
4
Repair or Recommendation
If the repair can be completed roadside (sensor replacement, wiring fix, DPF regen, injector replacement), we’ll provide a quote and do the work on-site. For complex internal engine repairs, we’ll give you a detailed diagnosis and recommend the next steps.
Common Engine Problems We Diagnose
Our mobile diagnostic service handles every type of diesel engine fault code and performance issue:
Check Engine Light / MIL On
From minor sensor faults to serious engine issues, we diagnose the cause of your check engine light and determine if it’s safe to continue driving or requires immediate repair.
Loss of Power / Derate Mode
Engine derates (limp mode) are protective responses to serious faults. We identify whether it’s DPF-related, turbo issues, fuel system problems, or sensor failures—and get you out of derate when possible.
DPF / DEF System Faults
DPF full warnings, DEF quality issues, NOx sensor failures, and SCR system faults. We can force regens, test DEF quality, and diagnose aftertreatment system problems on-site.
Hard Starting or No Start
Extended cranking, rough cold starts, or no-start conditions caused by fuel delivery issues, glow plug failures, air in fuel system, or ECM faults. We diagnose and repair most starting issues roadside.
ECM / Computer Module Failures
ECM corruption, software glitches, failed reprograms, or water-damaged modules. We can reflash ECMs, update software, and in some cases repair or replace computer modules on-site.
Overheating / Cooling System Codes
High coolant temp warnings, thermostat faults, coolant level sensors, and fan clutch issues. We diagnose cooling system faults and determine if it’s safe to continue driving.
Sensor Faults (MAF, MAP, IAT, Oil Pressure)
Faulty sensors send incorrect data to the ECM, causing poor performance, high fuel consumption, or derate conditions. We test sensor outputs and replace failed units on-site.
Turbocharger / Boost Pressure Issues
Low boost pressure codes, wastegate faults, VGT turbo actuator problems, and boost leaks. We diagnose turbo system faults and test for air leaks in the intake system.
Our Customer Service Promise
When you choose AZ Mobile Diesel Repair for engine diagnostics, you’re getting more than just a code reader—you’re getting expert analysis and honest recommendations.
Accurate Diagnosis, Not Guesswork
We don’t throw parts at a problem hoping something fixes it. Our technicians use OEM-level diagnostic tools, technical service bulletins, and years of diesel experience to identify the exact cause of your engine issue. You’ll get a clear explanation of what’s wrong and why.
If we find multiple issues, we’ll prioritize them: what needs immediate attention for safety, what’s causing your current symptoms, and what can wait. You make the final call on repairs.
No Diagnostic Fee If We Can’t Find the Problem
We’re confident in our diagnostic abilities. If we can’t identify the cause of your engine issue after a thorough scan and inspection, there’s no diagnostic charge. You only pay when we deliver answers.
For complex intermittent issues that require extended testing or road testing, we’ll discuss options upfront so you know what to expect.
We Repair What We Diagnose
Unlike shops that diagnose but can’t repair, we carry parts, tools, and expertise to fix most engine issues on-site. Sensor replacements, injector swaps, wiring repairs, ECM reprogramming—we complete the job at your location when possible.
For repairs that require shop-level work (internal engine repairs, head gasket replacement, etc.), we’ll provide a detailed written diagnosis and help coordinate the next steps.
Service Coverage Area
AZ Mobile Diesel Repair provides mobile engine diagnostics throughout the Phoenix Metro area and surrounding communities:
Major Corridors
I-10 (Buckeye to Apache Junction)
I-17 (Anthem to South Phoenix)
Loop 101, Loop 202, Loop 303
Cities We Serve
Phoenix, Mesa, Chandler, Tempe, Scottsdale, Glendale, Avondale, Tolleson, Goodyear, Surprise, Buckeye, Peoria, Gilbert, and all surrounding areas within 50 miles.
Not sure if we cover your area? Call us at (602) 456-9071 — we’ll confirm our ETA and dispatch a technician immediately.
Why Choose AZ Mobile Diesel Repair for Engine Diagnostics
OEM-Level Diagnostic Tools
We use factory-grade scan tools for Cummins, Detroit, Caterpillar, International, and Paccar engines. These aren’t generic code readers—they’re the same tools dealerships use for bi-directional testing, ECM programming, and advanced diagnostics.
ASE-Certified Diesel Technicians
Our technicians hold ASE certifications in diesel engine performance, electronic diagnostics, and engine repair. They’ve diagnosed thousands of diesel engine faults and stay current with manufacturer technical bulletins.
Fast Mobile Response
We arrive at your location within 30-60 minutes across Phoenix Metro. No need to limp to a shop or wait days for an appointment. We diagnose and often repair engine problems the same day, right where you’re parked.
Get Expert Engine Diagnostics Now
Check Engine Light On? We’ll Find Out Why.
Call now for mobile diesel engine diagnostics. Average response time: 30-60 minutes.
(602) 456-9071
Open 7 AM - 7 PM Daily for emergency engine diagnostics and repair across Phoenix Metro