DPF & DEF System Service
Aftertreatment fault codes, regen issues, and DEF failures live in one of the most expensive systems on a modern truck. We diagnose and repair DPF and DEF systems with the right tools and the patience to find root cause — not the parts cannon.
What’s included
Everything covered under this service, on-road or in the shop.
- Forced parked and active regens
- DPF cleaning and replacement
- DEF doser and injector service
- DEF quality and level sensor diagnosis
- NOx sensor (inlet / outlet) replacement
- SCR catalyst and EGR diagnosis
- Aftertreatment harness and connector repair
- Fault code tracing across J1939
- Soot accumulation and ash service
Why fleets and drivers choose T&T
We diagnose before we replace
NOx sensors run $400–$2,000+ each, doser pumps more. We test before we swap so you're not paying for a part that wasn't the problem.
OEM scan tools, not generic readers
Generic OBD readers don't give the depth needed for aftertreatment. We use the OEM tools — Insite, DDDL, Davie, ServiceMaxx — for the full datalink picture.
Documented repair history per truck
Aftertreatment problems often repeat. We log what we did and what we found so the next time it acts up we don't start from scratch.
Brands & systems we service
Frequently asked
- Why does my truck keep going into derate?
- Derate is the engine telling you the aftertreatment is failing or the DEF system isn't reducing emissions properly. Common culprits: failed NOx sensor, plugged DPF, low DEF quality, doser malfunction, or a leaking aftertreatment seal. We chase root cause — clearing the code without fixing the cause means you'll see it again.
- How much does a DPF cleaning cost vs. replacement?
- Cleaning is significantly cheaper than replacement. For most service intervals, cleaning is the right call. A DPF that's truly cracked or melted needs replacement — we'll show you which it is before we quote.
- Can you delete the DPF?
- No. EGR / DPF / DEF deletes are illegal under the federal Clean Air Act, with penalties up to $4,500 per violation per truck — and EPA enforcement against fleets has stepped up. We do not perform deletes. We will fix your aftertreatment so it works the way it should.
- What causes DEF crystallization?
- Usually a faulty doser, a leak letting air in, or contaminated DEF. Crystallization gets worse if ignored — what starts as a soft fault becomes a derate, then a stranding. Fix it early.
- How long does an aftertreatment repair take?
- A sensor replacement: a few hours. A full DPF service: half a day. A complex SCR or doser issue with chase-down: 1–2 days. We give you a real estimate after diagnosis, not before.
Get a truck back on the road.
Call us — most customers reach a real person in under 30 seconds.