How to clean a DPF filter

1. Passive and active regeneration

Your vehicle tries to clean its own filter. Passive regeneration happens naturally at motorway temperatures. Active regeneration injects extra fuel to raise exhaust temperature and burn the soot off.

If the light has only just come on, a 20 to 30 minute run at steady motorway revs in a lower gear often completes a regeneration. If the light stays on, stop trying — repeated failed regenerations dilute your engine oil.

2. Forced regeneration on diagnostics

We command a regeneration through the diagnostic tool while monitoring temperature, soot load and pressure. It works when the filter is loaded but not fully blocked, and it tells us immediately whether the filter is recoverable.

3. On-car chemical cleaning

Professional cleaning fluid is fed through the filter under pressure via the sensor port, breaking down soot and ash the vehicle cannot burn off, followed by a rinse and a regeneration. No removal, no cutting, and it restores flow on most blocked filters.

4. Off-car cleaning

For heavily ash-loaded filters, usually high mileage vans, the filter comes off the vehicle and is cleaned properly on the bench, then flow-tested before it goes back on.

Clean the filter, fix the cause

A clean filter blocks again within months if the reason it blocked is still there. Before we hand the vehicle back we check the usual suspects:

• ✓Leaking or worn injectors
• ✓Sticking or failed EGR valve
• ✓Faulty differential pressure sensor or blocked pipes
• ✓Boost leaks and split intercooler hoses
• ✓Glow plug and sensor faults blocking regeneration

Get it done in Salford

We handle DPF diagnostics, forced regeneration and cleaning from our workshop at M7 1UL, covering Manchester, Salford, Bolton, Bury, Oldham, Stockport, Trafford and the rest of Greater Manchester. Fixed price from £180, most vehicles same day.

Common questions