Light-Duty Diesel Repair

When a diesel engine has a drivability issue, hard start, low power, inducement derate, or strange electrical behavior, parts-swapping won’t solve it.  These aren’t simple mechanical failures, they’re often control system problems hiding behind incomplete data or misleading fault codes.

At Keeney Auto & Diesel, diesel diagnostics are handled with the same toolset and precision as high-end network and module work.  Every concern, whether it’s fuel pressure fluctuation, regen failures, or cam/crank correlation, is diagnosed by waveform analysis, scan data, and specs.  No guesswork.  No blind repairs.

Clients from Soddy-Daisy, Chattanooga, and across the region trust us with diesel trucks that others may have  trouble diagnosing, especially when the check engine light won’t go away, a module won’t program, or factory scan tools fall short.  This isn’t your basic fuel filter change shop, we handle what many avoid. 

• Cummins 5.9L, 6.7L — RAM 2500/3500+ 
• Chrysler 3.0L EcoDiesel (all generations) — RAM 1500, Jeep Grand Cherokee, Wrangler, Gladiator
• Duramax LB7–L5P — Chevy/GMC 2500HD/3500HD+ 
• Duramax 2.8L I4 / 3.0L I6 — "Baby Duramax" in Colorado, Canyon, Silverado 1500 
• Ford Power Stroke 7.3L, 6.0L, 6.4L, 6.7L — Super Duty platforms 
• Ford 3.0L V6 Diesel — Found in F-150 and select Land Rovers 
• Sprinter 2.1L & 3.0L — Light-duty applications 
• VW/Audi TDI engines — 1.9L, 2.0L, and 3.0L diesels (U.S.-market only) 
• BMW Diesel Engines — 3.0L inline-6 (found in 335d, X5d, etc.)
   

These vehicles are tested using manufacturer-grade procedures and advanced signal tools, not just generic code readers.

There are a few persistent issues plaguing the light duty diesel segment.  Some common problem areas include:

• Fuel Injectors and High-Pressure Fuel Pumps
• Diesel Particulate Filters (DPFs)
• Exhaust Gas Recirculation (EGR)
• Diesel Exhaust Fluid (DEF) Systems
• Selective Catalytic Reduction (SCR) Converters

These issues just never seem to go away.  To make it worse, I have direct experience with issues in the field that are straight up software design flaws for which there is actually no fix.  Despite this demoralizing truth, there is hope.  Regardless of the failure condition, we can identify and explore options that will suit your needs.

• No-start or long crank 
• Slow crank 
• White or excessive smoke 
• Regen cycle not completing 
• Injector circuit faults 
• DPF or EGR issues 
• Fuel rail pressure anomalies 
• Crankshaft/camshaft correlation codes 
• CAN network dropout
   

Each system is tested using voltage drop, current ramping, oscilloscope waveforms, and known-good signal comparison, not parts-hoping.

• Hard-start or no-start diagnostics on Duramax, Cummins, and Powerstroke 
• Electrical faults, intermittent no-boost, or derate issues 
• Diesel control module coding and programming 
• Advanced waveform and sensor diagnostics 
• Aftermarket turbo and fuel system support 
• Regeneration faults and DEF system diagnostics 
• Repair and calibration of emission-critical modules when new ones are unavailable

I have yet to encounter a shop that will say "no" to a diesel owner, irrespective of that auto mechanic shop's actual capability or competence.  The service writer will be quick to tell you that of course they work on diesels, but assuredly, will neglect to tell you that the only diesel work they've done was just an oil change and the lube kid put 5w-30 back in it.  

Owning a diesel doesn't preclude you from patronizing a conventional repair facility.  At the same time, ensuring that your diesel is receiving service that is congruent with its engineering design, is invaluable for its longevity.   

Whether you’re a shop looking for a second opinion or a driver stuck with a mystery problem, this is where complex diesel issues come to get solved.

→ Schedule diagnostic testing today.