MTO Approved· 5900 Dixie Rd, Unit 13, Mississauga ON L4W 1E9· Mon–Sat 9 AM – 6 PM Talk to a tech: (905) 677-7663
Home/Services/Truck Won’t Regen? Diagnostics in MississaugaFailed regen

Truck Won’t Regen? Diagnostics in Mississauga

A regen request that keeps returning is telling you the aftertreatment system is not reaching or sustaining the conditions it needs. Clearing the warning without finding why usually brings the truck back.

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Independent commercial truck repairMississauga shopWritten findings before repairFleet & owner-operator support
What the symptom can mean

Several systems can create the same driver complaint.

A symptom page is not a diagnosis. Vehicle year, make, model, VIN, active faults and operating conditions determine the correct test path.

  • Regen will not start
  • Regen starts but does not complete
  • DPF light returns shortly afterward
  • Soot-load warning increases
  • Truck begins to derate
What to do next

Capture information before it disappears.

If the vehicle is safe to do so, record what happened before cycling the key or clearing faults.

  • Photograph warning messages
  • Record fault codes if available
  • Note speed, load and temperature when it happened
  • Tell us whether the problem is constant or intermittent
  • Stop operating if a red stop warning or unsafe condition is present
Frequently asked questions

Truck Won’t Regen? Diagnostics in Mississauga — answered.

Can you diagnose this without seeing the truck?

We can help determine urgency from the information you provide, but a repair diagnosis generally requires testing the vehicle.

Should I clear the codes before bringing it in?

If possible, avoid clearing codes because stored fault and freeze-frame information can help diagnosis.

What if the truck is unsafe to drive?

Do not continue operating an unsafe commercial vehicle. Arrange appropriate roadside or towing support and contact the shop with the symptoms.

Book service

Tell us what the truck is doing.

Have the year, make, model, VIN, mileage, warning lights or fault codes, and whether the truck can be driven safely.

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Mr Diesel Inc. · 5900 Dixie Rd, Unit 13, Mississauga ON L4W 1E9