MTO-approved inspection station 1180 Midway Blvd, Unit 5 · Mississauga ON Mon–Sat 09:00–18:00 ET Talk to a tech: (905) 677-7663

(905) 677-7663 Book a bay

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DPF cleaning, derates & aftertreatment repair

Failed regens, DEF faults, NOx sensors and 5-mph derates traced to the cause with OEM software at 1180 Midway Blvd. We clean or replace the filter and clear the codes. You get a written quote before any work starts.

Call (905) 677-7663 Request a slot

Aftertreatment EPA 2010+

DPF

Clean or replace

DEF / SCR

Dosing & sensors

OEM

Scan software

Quote

Before any work

Bring the fault codes, or a photo of the dash warning lights. It saves diagnostic time.

What we fix

The whole exhaust system, not just the filter.

A blocked DPF is usually a symptom. We find what caused it so the filter doesn't clog again next month.

DPF cleaningFilter removed, thermally cleaned and flow-tested, or replaced if it is cracked or too full of ash to clean.

DOCFace-plugging and fuel fouling checked. Cleaned or replaced along with the DPF.

Forced & parked regensRun with OEM software while we watch temperatures and pressures live.

DEF & SCR dosingDoser, pump, lines, heaters and DEF quality. Crystallised dosers cleaned or replaced.

NOx & temperature sensorsInlet and outlet NOx, EGT and DPF pressure sensors tested before anything is replaced.

EGR valve & coolerSticking valves and leaking coolers, two of the most common causes of soot overload.

Derate clearingRoot cause fixed first, then the derate cleared and the truck road-tested.

Upstream causesInjectors, turbo, boost leaks and oil consumption that load the filter faster than it can regen.

Fault codes

The aftertreatment codes we see most.

SPN numbers are the J1939 standard. Each engine maker adds its own fault code on top, so bring both if your dash shows them.

SPN 3251

DPF differential pressure

Filter loaded, or a faulty pressure sensor or sensor lines.

SPN 3719

DPF soot load

Soot above the regen threshold. Regens failing or being interrupted.

SPN 4364

SCR conversion efficiency

NOx not being reduced. DEF quality, doser or catalyst problem.

SPN 3364

DEF quality

Diluted or contaminated DEF, or a failing quality sensor.

SPN 3226

Outlet NOx sensor

Reading out of range. Often what triggers a derate.

SPN 3216

Inlet NOx sensor

Sensor or wiring fault upstream of the SCR.

SPN 1761

DEF tank level

Level sender or tank heater fault, or simply low DEF.

SPN 5246

SCR inducement

The derate itself. The engine limits power until the cause is fixed.

Book it

Get the truck out of derate.

Send the fault codes and what the truck is doing. If you're derated and can't get here, see mobile repair.

Derated right now? (905) 677-7663

Clean or replace the DPF?+

Most filters can be cleaned. We replace one when it is cracked, melted or too full of ash to clean, and we show you the readings either way.

Will a forced regen fix it?+

Sometimes, if the filter isn't too loaded and the cause was short trips or idling. If regens keep failing, something upstream needs fixing first.

Can you delete the DPF?+

No. Deletes are illegal in Ontario, fail the annual inspection and void emissions compliance. We repair the system so it works.