J1939, OEM fault information, lab reports, failure evidence and newer fuel technologies. These pages focus on the evidence and decisions relevant to advanced diesel diagnostics, with attention to safely identifying the actual cause before ordering expensive diesel injection components.
Explore this collection alongside the Technical Journal, the diesel code center and the nationwide mail-in service. The articles explain what to capture and when to involve a qualified specialist; they do not replace OEM diagnostic procedures.
Guides in this collection
Real Diesel Injection Repair Case Studies: What the Evidence Should Show
Understand credible case-study documentation and what is needed before DCT can publish authentic customer cases.
Diesel Fuel Analysis: Reading a Laboratory Report
Understand water, particulate and fuel-quality findings without overinterpreting a single sample.
Renewable Diesel (HVO) Versus Biodiesel: Older Injection System Considerations
Explain HVO/renewable diesel, biodiesel blends, specifications and cautions for legacy injection equipment.
J1939 SPN/FMI Fuel Injection Faults: A Practical Guide
Navigate heavy-duty diesel SPN and FMI information without assuming a universal component verdict.
SPN/FMI Versus OBD-II P-Codes: What Diesel Technicians Need to Know
Compare heavy-duty J1939 diagnostics with generic P-codes and manufacturer-specific engine faults.
OEM Diesel Fault Codes: John Deere, Caterpillar, Cummins and Others
How to interpret manufacturer-specific diesel injection faults without unsafe cross-brand assumptions.
Diesel Injection Failure Photo Atlas: What Real Evidence Should Show
A guide to documenting corrosion, scoring, deposits and contamination without mislabeling illustrative images.
Injection Pump Case Studies: Before-and-After Test Evidence
Understand the essential fields of authentic pump repair case studies and why real measured outcomes matter.
Diesel Fuel Sample Results: Water, Particles and Filter Plugging
Interpret the most actionable observations in a diesel fuel sample and decide what further evidence is needed.
Injector and Pump Compatibility by Engine Generation and Part Number
How to verify injection-component fit using engine build, suffix, OEM supersession and calibrations.
How to use these guides
Begin with equipment identification and the exact symptom, then review related tests and technical limitations. Where an article calls for a high-pressure fuel-system test or physical inspection, employ trained personnel and current manufacturer information. DCT does not guarantee repair, pricing or turnaround for an unidentified component.