DPF & Aftertreatment
Repair
Concord, NC
A derated truck costs hundreds per day in lost revenue. CTR diagnoses why your aftertreatment failed — not just what failed — so we fix the root cause and prevent repeat failures.
Aftertreatment Repair Experts
The aftertreatment system — DPF, DOC, SCR, DEF, and EGR — is a chain of interconnected components. A problem in one affects the others. Most shops replace the component that triggered the fault code. CTR investigates why it failed.
Worn injectors producing excessive soot. Oil consumption coating the DOC and DPF. EGR failures increasing soot loading. Coolant intrusion contaminating catalysts. Fix only the symptom and you're back in the shop within months. Fix the root cause and the system stays healthy.
CTR uses OEM diagnostic tools for every platform — Cummins INSITE, Detroit DLA, PACCAR Davie, Navistar ServiceMaxx. Derated trucks are prioritized. All repairs backed by our 3-year, 36,000-mile warranty.
Root Cause Focus
We fix WHY the aftertreatment failed, not just what failed. Prevents repeat failures.
OEM Diagnostics
Full access to aftertreatment data, forced regen, SCR efficiency testing on all platforms.
30+ Years Experience
Diagnosing diesel emissions systems since they were introduced. Every failure pattern, every platform.
Priority Derate Service
Derated trucks are prioritized — we know you cannot afford to wait.
3-Year, 36K Warranty
Every aftertreatment repair backed by industry-leading warranty.
Cleaning Before Replacing
Professional DPF cleaning at 20–30% of replacement cost. We only replace when necessary.
Complete Aftertreatment Repair Services
Every service starts with root cause diagnosis. Click any service for details.
Before recommending DPF replacement ($2,000–$5,000+), we diagnose the actual condition. Soot load analysis, backpressure testing, and forced regeneration are performed in-house. For filter cleaning, CTR partners with a certified facility for professional pneumatic and thermal cleaning. We handle removal, reinstallation, and post-cleaning verification.
Warning Signs of Aftertreatment Failure
Aftertreatment problems escalate through a derate progression that can shut your truck down to 5 mph.
Check Engine / DPF Light
Aftertreatment fault detected. Address promptly before derate progression begins.
Power Reduction (Derate)
Engine power reduced 25–50%. Truck operates but with significantly reduced performance.
5 MPH Speed Limit
Most severe derate — truck effectively immobilized. Emergency repair required.
Frequent Regeneration
Engine producing more soot than normal or DPF ash accumulation reducing capacity.
White Exhaust Smoke
Possible SCR problem, coolant leak, or injector issue. Diagnosis needed.
Stuck in Regen
Engine cannot reach temperature needed to burn soot. DOC, fuel doser, or sensor failure.
Derate Progression
25% Power Reduction
Initial derate. Truck runs but with noticeably reduced power.
40–50% Power Reduction
Escalated derate after initial fault is not resolved.
5 MPH Speed Limit
Most severe derate. Truck effectively immobilized.
Aftertreatment Repair Cost Guide
| Service | Cost Range |
|---|---|
| Forced Regeneration | $200–$400 |
| DPF Cleaning (Professional) | $600–$1,200 |
| NOx Sensor (each) | $400–$800+ |
| DEF Dosing Unit | $500–$2,000 |
| EGR Valve/Cooler | $500–$2,500+ |
| DOC Replacement | $1,000–$3,000+ |
| DPF Replacement | $2,000–$5,000+ |
| SCR Catalyst Replacement | $2,000–$5,000+ |
| Complete System | $5,000–$15,000+ |
Written estimates provided before any work begins. All repairs backed by 3-year, 36,000-mile warranty.
DPF Cleaning Methods (Certified Partner)
Pneumatic Cleaning
Compressed air in reverse direction to dislodge ash. Performed by our certified cleaning partner. Effective for light accumulation.
Best for: Light ash, routine maintenanceThermal Cleaning (Bake)
Heats DPF to ~1,100°F in controlled oven to burn remaining soot, followed by pneumatic ash removal. Performed by our certified cleaning partner.
Best for: Heavy soot + ash, maximum restorationCombination Cleaning
Pneumatic + thermal for maximum restoration of flow capacity. CTR handles removal, reinstallation, and post-cleaning testing.
Best for: Severely loaded DPFs, best resultsAftertreatment Deletes Are Illegal
Removing emissions controls violates the Clean Air Act — penalties up to $5,000/individual and $500,000+/business. CTR repairs systems to function as designed.
Understanding Your Aftertreatment System
The aftertreatment system is a chain of components — each stage treats a different pollutant. Understanding the chain helps you understand the repair.
DOC (Diesel Oxidation Catalyst)
Stage 1 — oxidizes carbon monoxide and hydrocarbons. Also raises exhaust temperature during active regeneration to help burn soot in the DPF.
DPF (Diesel Particulate Filter)
Stage 2 — captures soot from the exhaust. Requires regeneration to burn soot. Ash accumulates over time and must be professionally cleaned.
SCR (Selective Catalytic Reduction)
Stage 3 — uses DEF to convert nitrogen oxides (NOx) into harmless nitrogen and water. Monitored by upstream and downstream NOx sensors.
DEF Dosing System
Support — tank, pump, lines, dosing valve, quality sensor. Any component failure triggers aftertreatment faults and engine derates.
EGR (Exhaust Gas Recirculation)
Pre-stage — recirculates exhaust gas to lower combustion temperatures and reduce NOx formation. EGR failures affect engine performance and downstream loading.
Built for Heavy Duty
CTR's facility on Armentrout Drive has the OEM diagnostic tools and bay space for complete aftertreatment diagnosis, removal, reinstallation, and testing on Class 3 through Class 8 trucks. For DPF filter cleaning, CTR partners with a certified cleaning facility that performs professional pneumatic and thermal cleaning — we handle everything else in-house. Directly off I-85 at Exit 58.
Fleet Aftertreatment Maintenance
CTR includes aftertreatment system monitoring in fleet PM programs — DPF soot/ash load tracking, regeneration frequency monitoring, DEF system inspection, and proactive cleaning scheduling. Prevent derate events before they happen.
(704) 786-0132
Aftertreatment Repair Near You
CTR Heavy Duty — Concord
Directly off Interstate 85 at Exit 58. Easy truck access.
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Aftertreatment FAQ
16 common questions about DPF, aftertreatment, and derate repair.